Top 12 Cancer Fighting Supplements of 2024: 1,000+ Studies Analyzed - Part 1

Can supplements, diet, and lifestyle influence cancer risk? Can you supplement your way out of cancer?

The true story of cancer-fighting supplements is out there. We have compiled and analysed over 1,000 research studies, journal sources, and peer-reviewed papers to uncover the truth.

This article dives into the research to answer critical questions:

• Supplement Savvy: Can vitamins and minerals help, or even hinder, cancer prevention?
• Beyond the "Anti-Cancer" Label: This term can be misleading. We'll discuss supplements that may play a role in both prevention and supporting treatment.

Many studies have showed that simple diet and lifestyle changes and natural compounds can actually “reprogram” cancer cells…and shut off some of their most notorious defense mechanisms.

Current AI (artificial intelligence) tools like ChatGPT, Gemini from Google and Copilot from Microsoft might return generic answers to your questions. While these can be a starting point, they often lack the depth you might crave.

Note: This is part 1 in Unveiling the Science Behind Cancer, Diet and Supplements series. Check out part 2: Can Diet and Lifestyle influence your Risk of getting Cancer? 1,000+ Studies Analyzed (2024)

While your cancer specialist or oncologist may not dive deeply into diet, lifestyle and supplements during consultations, these aspects can be crucial for your well-being.

These natural diet and supplement strategies can be found in some common, everyday items available in any neighbourhood supermarket.

So why isn’t it making headlines as the greatest cancer breakthrough of the 21st century?

Traditional mainstream media often overlooks preventive measures due to a profit-driven focus. This leaves many people confused about the role of diet and supplements in cancer prevention. We have to shovel through a lot of dirt to find the gold.

According to a 2024 study results, published in Lancet Global Health journal, 99.3 percent of the global population is missing at least one important nutrient. The study collected data from 31 countries to estimate micronutrient consumption in 185 countries.

Surprisingly, it really is illegal for a supplement company, for example, to list the specific health benefits of their products on the label. They can provide general information about how nutrients affect the structure or function of the body, but they can’t tell you that their supplement, for example, lower blood sugar. Why not? 

For a supplement to market their product for a specific medical benefit, they will have to go through the same steps that drugs do to get approved. Simply put, this would cost hundreds of millions of dollars for natural substances that, because they can’t be patented, don’t enjoy the same market protections synthetic drugs do. Most supplement companies do not have huge capital. How could any one of them afford to spend hundreds of millions of dollars for studies when they won’t recoup that investment on the other end?

That said, the FDA doesn't strictly regulate supplements. Their safety and effectiveness may vary. With so many options, choosing the right ones can be overwhelming. Always consult your doctor first! Some supplements can interact with medications or cause side effects, especially during cancer treatment.

Credit: FLCCC Alliance

This article explores some supplements with potential to prevent cancer or aid recovery. We'll also analyze relevant studies, keeping in mind that new research emerges constantly.

Methodology

We’ve combed the internet, find the best references and reviewed over 1,000 studies so that you don’t have to. 

When interpreting and filtering scientific research, it’s crucial to consider the hierarchy and quality of evidence. Not all evidence is equal.

Cell culture findings carry less weight than results from studies conducted on mice. Similarly, conclusions drawn from mouse studies are surpassed by findings from human studies.

Case studies and preliminary results from small-scale human trials hold less significance than outcomes from umbrella reviews, systematic reviews and meta-analysis*, randomised controlled trials (RCTs), and more extensive, long-term human trials.

*A systematic review is a review that collects, critically appraises, and synthesizes all the available evidence to answer a specifically formulated research question. A meta-analysis, on the other hand, is a statistical method that is used to pool results from various independent studies, to generate an overall estimate of the studied phenomenon.

It would be impossible to review all the studies on the internet; rather, we have focused on, curated and evaluated the information that appear to have the greatest clinical utility. 
 

Contents:

1. Best Anti Cancer Supplements (Evidence-based)
1. Vitamin D3 and K2
2. Turmeric (Curcumin)
3. Fish Oil (Omega-3 Fatty Acids)
4. Vitamin C
5. Magnesium and Molecular Hydrogen
6. Green tea (EGCG)
7. Quercetin
8. Melatonin
9. Zinc
10. Garlic (Allicin)
11. Vitamin B2 (riboflavin) and B3 (niacinamide)
12. Probiotics
2. Can antioxidant supplements help prevent cancer?
3. Causes of Cancer
4. Diet and Cancer Prevention
5. Don't use tobacco
6. Alcohol and Cancer
7. Maintain a healthy weight and be physically active
8. Fasting and Cancer
9. Avoid risky behaviors
10. Sleep Quality, Stress and Desk Job
11. Protect yourself from the sun
12. Get regular medical care and Health Screening
13. Avoid unnecessary exposure to radiation.
14. Avoid exposure to environmental toxins and infections that contribute to cancer

Best Cancer Fighting Supplements: Evidence Based

What vitamins minerals etc can help fight cancer?

We have ranked the top 10 cancer fighting supplements to help you with your research. We have also organised and summarised relevant and salient research information in one place. Below, we look at the most published and studied categories.

Important Note: This information is for educational purposes only and should not be interpreted as medical advice.

Here is the list (listed in order of importance):

1. Vitamin D3 and K2

Is vitamin D the most powerful anti cancer supplement? Vitamin D can absorb calcium and help the immune, muscle, and nervous systems function properly. There are more than 12,000 search results on vitamin D and cancer on PubMed. 

Vitamin D and Cancer Prevention

A 2023 systematic review and meta-analysis of 14 RCTs (randomized controlled trials), published in Ageing Research Reviews (Kuznia 2023) found vitamin D3 supplementation reduced cancer mortality by 6%. This wasn’t considered statistically significant, but when only studies involving daily vitamin D intake were analyzed, cancer mortality dropped by a significant 12%.

In a 2023 meta-analysis, 116 randomised controlled trials were analysed. The meta-analysis concluded that vitamin D reduces lung cancer mortality. All-cause mortality* is decreased in patients with COVID-19 and liver diseases, especially in liver cirrhosis.

*Note: "Death from anything" may be a clearer term for the layperson as opposed to 'All-cause mortality'. This is one of the best measures for the factors that increase the risk of what eventually and most likely will take someone's life.

A 2022 randomized-controlled trial (DO-HEALTH) trial to investigate the combination of three complementary treatments for the prevention of cancer and suggest that the combination of daily vitamin D3, supplemental marine omega-3s, and a simple home exercise program may be effective in the prevention of invasive cancer among generally healthy and active adults aged 70 and older. Findings from a 3 year Randomized Controlled Trial with more than 2,000 participants observed a 61% reduction in the risk of invasive cancer among patients who completed a home exercise program and took vitamin D3 and omega-3 fatty acids daily. These results, from the DO-HEALTH trial (ClinicalTrials.gov identifier NCT01745263), were published in Frontiers in Aging 2022.

Dosage (DO-HEALTH): Supplemental 2000 IU/day of vitamin D3, and/or 1 g/day of marine omega-3s, and/or a simple home strength exercise (SHEP) programme compared to placebo and control exercise.

A comprehensive meta-analysis published June 18, 2024, in the journal Frontiers in Nutrition, examined the existing evidence surrounding this topic, highlighting the importance of maintaining optimal vitamin D levels as a potential protective strategy against thyroid cancer. The meta-analysis analyzed data from 21 studies involving 2,434 patients with thyroid cancer and 7,398 controls. The researchers focused on two key forms of vitamin D — 25-hydroxyvitamin D (25 (OH)D), a marker of overall vitamin D status, and 1,25-hydroxyvitamin D (1,25 (OH)D), the active form of the vitamin.

A number of epidemiologic studies have also investigated whether people with higher vitamin D intakes or higher blood levels of vitamin D have lower risks of specific cancers. The results of these studies have been inconsistent, possibly because of the challenges in carrying out such studies. For example, dietary studies do not account for vitamin D made in the skin from sunlight exposure, and the level of vitamin D measured in the blood at a single point in time (as in most studies) may not reflect a person’s true vitamin D status. Also, it is possible that people with higher vitamin D intakes or blood levels are more likely to have other healthy behaviors. It may be one of these other behaviors, rather than vitamin D intake, that influences cancer risk.

A Secondary Analysis of the VITAL* Randomized Clinical Trial studied the effect of Vitamin D3 Supplements on Development of Advanced Cancer. The Harvard research, published in the JAMA Network Open medical journal (2020), overturns the initial findings of a study of 25,000 people published in 2018.

*The VITamin D and OmegA-3 TriaL (VITAL) is a study to assess whether taking vitamin D (2000 IU/ day) and omega-3 fatty acids from marine (oily fish) sources lowers the risk of cancer.

Initially researchers believed there was no benefit from taking vitamin D, as they detected no reduced incidence of cancer diagnoses overall. But they were puzzled because cancer deaths went down among those taking the supplements. Meaning, there was no benefit in terms of prevention of cancer but a reduction in cancer deaths was observed.

A secondary analysis, found this anomaly can be explained by the fact that vitamin D seems to stop metastatic cancers - those aggressive types which spread to other parts of the body. That said, when stratified by BMI (body mass index), there was no significant reduction for the vitamin D arm in incident metastatic or fatal cancer among those with overweight or obesity (BMI 25-<30).

The cancers for which the most human data are available are colorectal, breast, prostate, and pancreatic cancer. Numerous epidemiologic studies have shown that higher intake or blood levels of vitamin D are associated with a reduced risk of colorectal cancer (Meta-analysis 2011). 

According to BreastCancer.org, research suggestsTrusted Source that certain cancers such as breast cancer, can have a higher risk of occurring when the body has low levels of vitamin D. 

Studies also show a link between vitamin D deficiency and cardiovascular disease, diabetes, and cancer (Sizar, 2020).

Many experts now recommend 800 to 1,000 IU a day, a goal that's nearly impossible to attain without taking a supplement. Although protection is far from proven, evidence suggests that vitamin D may help reduce the risk of prostate cancer, colon cancer, and other malignancies.

Although the role of vitamin D in cancer prevention remains an area of research interest and debate, avoiding deficient levels is recommended. (American Cancer Society 2020)

Dietary sources of Vitamin D include fatty fish, egg yolks, salmon, sardines, cod liver oil, some yogurt (read the label to see if it says "fortified with vitamin D"), some soy milk (read the label to see if it says "fortified with vitamin D") and fortified milk. Sun exposure is also another way to get vitamin D naturally.

Make sure to take 500 mg to 1000 mg of magnesium and 150 mcg of vitamin K2, (not K1) which are important cofactors for optimizing vitamin D function. And, remember the only way you know what your vitamin D level is, is to test it. Vitamin D level should be in a therapeutic range of 50 to 70 ng/ml for treatment of rheumatoid arthritis. Most people are shocked how low their level is when they finally get around to testing it.

That said, as researchers explained in Nutrients (2022):

“Vitamin D supplementation is not the magic pill that miraculously solves the cancer burden or that can replace a healthy lifestyle. It is necessary to foster a good environment and invigorate a healthy lifestyle, including a high-quality diet and physical activity. Both have been proven to confer health benefits in many diseases, including cancer, and are the best preventive measures available.”

 

Related: Vitamin D Level and Cancer: Vitamin D Reduces Cancer Deaths

The Optimal Vitamin D Level for Cancer Prevention

Research has shown that once you reach a minimum serum vitamin D level of 40 ng/mL (100 nmol/L), your risk for cancer diminishes by 67%, compared to having a level of 20 ng/mL or less. 

For health and disease prevention, including cancer prevention, we recommend you aim for optimal levels between 60 ng/mL and 80 ng/mL. 

It's important to remember that calcium, vitamin D3, magnesium and vitamin K2 must be properly balanced for optimal overall health. Your best and safest bet is to simply eat more calcium-, magnesium- and vitamin K2-rich foods, along with sensible sun exposure.

However, if you find supplementation is necessary after a serum vitamin D test, also supplement with magnesium and vitamin K2 (MK-7) to ensure proper balance. You'll also want to ensure you're following an overall healthy lifestyle to reduce your cancer risk as much as possible. As researchers explained in Nutrients (2022):

"Vitamin D supplementation is not the magic pill that miraculously solves the cancer burden or that can replace a healthy lifestyle. It is necessary to foster a good environment and invigorate a healthy lifestyle, including a high-quality diet and physical activity. Both have been proven to confer health benefits in many diseases, including cancer, and are the best preventive measures available."

Treatment

A 2024 post hoc analysis (Nutrients 2024) of the AMATERASU trial (UMIN000001977), a randomized controlled trial (RCT), included 302 patients with digestive tract cancers divided into two subgroups stratified by median serum levels of omega-3 into higher and lower halves. The 5-year relapse-free survival (RFS) rate was significantly higher in the higher half (80.9%) than the lower half (67.8%). In the patients in the lower omega-3 group, the 5-year RFS was significantly higher in the vitamin D (74.9%) than the placebo group (49.9%). In patients with digestive tract cancers, these results suggest that vitamin D supplementation may reduce the risk of relapse or death by interacting with marine omega-3.

Vitamin D and Chemotherapy

Multiple studies indicate that a significant proportion of cancer patients are vitamin D-deficient (level < 20 ng/mL) and that higher plasma 25-hydroxyvitamin D levels are associated with improved survival in colorectal, breast, gastric, and lymphoma cancer patients [Systematic Review 2014]. Meta-analyses and clinical trials demonstrate that vitamin D supplementation may reduce cancer mortality and improve survival in cancer patients, especially when used in combination with chemotherapy (Meta-analysis 2023). SUNSHINE (JAMA 2019), a clinical trial on metastatic colorectal cancer patients, showed that “high-dose” vitamin D3 (aiming for a level of >50 ng/mL) combined with standard chemotherapy resulted in improved progression-free survival compared to standard-dose vitamin D3.

Caution: The dosage for vitamin D in prevention (1,000 to 2,000 IU daily) is very much different from the high dose treatment dosage i.e. 20,000 to 50,000 IU daily. Always consult your doctor first! 

2. Turmeric (Curcumin)

What about turmeric and cancer? Curcumin, a vibrant yellow polyphenol derived from the turmeric plant (Curcuma longa), boasts an impressive range of bioactive properties.

Interestingly, curcumin has displayed antitumor properties both in vitro and in vivo, and has been shown to act through multiple cellular pathways. It is one of the few compounds that has progressed to clinical trials (source).

Curcumin is one of the nutrients with the most evidence-based literature supporting its use against cancer. There are more than 7,000 search results on curcumin and cancer on PubMed and more than 50 clinical trials with curcumin, most of which are still ongoing. The spice turmeric can be extremely helpful when it comes to fighting cancer. 

The use of fenbendazole and curcumin, has achieved much attention due to the reported experience of Joe Tippens. In 2016, Tippens was diagnosed with non-small-cell lung cancer with extensive metastatic disease. At the advice of a veterinarian friend, he took Fenbendazole together with nanocurcumin, and three months after starting these drugs his PET scan was completely clear. 

A review paper published in 2022, analysed 21 human studies. Sixteen out of 21 clinical trials were associated with the effectiveness of curcumin or turmeric on various types of cancer, and the other five clinical trials were related to the evaluation of the efficacy of curcumin or turmeric in relieving the side effects of cancer chemotherapy and radiotherapy. The emerging data from the clinical trials confirm that curcumin has the potential for cancer prevention and intervention. Interestingly, curcumin appears to be universally useful for just about every type of cancer (Arslan 2022), which is really odd since cancer consists of a wide variety of different molecular pathologies.

Both curcuminoids and related turmeric products have been sanctioned by the U.S. Food and Drug Administration (FDA) as safe.

Why Whole Turmeric Is Ineffective

Unfortunately, while there's some curcumin in whole turmeric, there's not enough in the regular spice to achieve clinically relevant results. The turmeric root itself contains only about 3% curcumin concentration. Another major limitation of curcumin as a therapeutic agent is that it is poorly absorbed. When taken in its raw form, you're only absorbing about 1% of the available curcumin.

Because it's not easily absorbed through your gastrointestinal tract, it's more effective to use a high-quality bioavailable curcumin extract, according to a 2013 study. A typical anticancer dose is just under 1 teaspoon of curcumin extract three or four times daily.

However, in the case of colon cancer, this poor absorption into the bloodstream may be an advantage. As there is poor absorption, higher levels of curcumin stay in the intestinal tract for longer periods of time, having an effect on gastrointestinal cancers. 

In one study, participants took a 1,080 milligram (mg) dose per day of curcumin for 10 to 30 days between their initial biopsy and surgical removal. The patients taking the supplement experienced a reduction in blood levels of inflammatory agent, improvement in their body weight and an increased number of dying tumor cells.

In a 2016 study, a team of scientists at the University of Pittsburgh and at Pondicherry University, India, discovered the bioactive ingredient in turmeric, curcumin, can both prevent and cure bowel cancers. The team found the compound triggered cancer cell death by increasing a level of protein labeled GADD45a. Lead author Rajasekaran Baskaran, Ph.D., who has more than 20 years of experience in cancer research, commented:

"Studies on the effect of curcumin on cancer and normal cells will be useful for the ongoing preclinical and clinical investigations on this potential chemo-preventive agent."

New Curcumin Forms

Convenience and efficiency has driven many of the changes in the forms of curcumin in later years. Because it's a fat-loving or lipophilic molecule, many newer preparations now include some sort of oil or fat, which improves its absorbability and bioavailability. Such preparations typically have seven to eight times higher absorption than the raw, unprocessed 95% concentration of dry powder. There are also newer sustained release preparations.

Turmeric and black pepper each have health benefits, due to the compounds curcumin and piperine. As piperine enhances curcumin absorption in the body by up to 2,000%, combining the spices magnifies their effects. (Healthline)

Click here to buy Bioavailable Curcumin. (Disclosure: Paid link)

  

Note: Although the antitumor properties of curcumin have been confirmed by multiple pre-clinical and clinical studies, its transition into mainstream cancer treatment has been limited by its subpar bioavailability. Furthermore, clinical investigations on curcumin have often involved small cohorts, which can lead to clinical variability. As a result, more expansive and well-structured clinical trials are required in the future to confirm that curcumin is a potential therapeutic agent for the treatment of cancer.

3. Fish Oil (Omega-3 Fatty Acids)

PubMed has indexed more than 3,000 research studies on Omega-3 and cancer. Most people use fish oil supplements to enhance the amount of omega-3’s in their diet. 

A 2021 report (Nature Communications) suggest that higher levels of omega 3 fatty acids in circulation correlate with lower risk of premature death from age-associated diseases such as cardiovascular disease and cancer. The analysis was conducted with data from 17 prospective cohort studies examining the associations between blood omega-3 fatty acid levels and risk for all-cause mortality. Over a median of 16 years of follow-up, 15,720 deaths occurred among 42,466 individuals. The researchers found that, after adjustment for relevant risk factors, risk for death from all causes was significantly lower (by 15-18%, at least p < 0.003) in the highest vs the lowest quintile for circulating long chain (20-22 carbon) omega-3 fatty acids (eicosapentaenoic, docosapentaenoic, and docosahexaenoic acids). Similar relationships were seen for death from cardiovascular disease, cancer and other causes. 

The first randomized-controlled trial (DO-HEALTH trial) to investigate the combination of three complementary treatments for the prevention of cancer and suggest that the combination of daily vitamin D3, supplemental marine omega-3s, and a simple home exercise program may be effective in the prevention of invasive cancer among generally healthy and active adults aged 70 and older.

Findings from a 3 year Randomized Controlled Trial with more than 2,000 participants observed a 61% reduction in the risk of invasive cancer among patients who completed a home exercise program and took vitamin D3 and omega-3 fatty acids daily. These results, from the DO-HEALTH trial, were published in Frontiers in Aging 2022.

 

Many governments recommend eating omega-3 containing fatty fish, two times per week. But that is often not enough. Ideally, people would need to eat fatty fish four times per week, while also supplementing with omega-3 fatty acids, at least 1,000 mg of pure omega-3 (DHA and EPA) per day.

However, fish oil was shown in one study on mice (2015)Trusted Source to possibly reduce the effectiveness of chemotherapy, and for that reason ground flax seed is a worthy alternative.

Flax seed is rich in omega-3 fatty acids, which may reduce the risk of certain cancers. When supplementing, try to avoid flaxseed oil because it lacks the nutrients of ground flax seed. Ground flax seed can be purchased online or found in many larger grocery store chains. Simply sprinkle some ground flax seed on your food and enjoy.

Make sure you buy high-quality omega-3 fatty acid supplements, meaning that the omega-3 fatty acids are pure and have not oxidized much (having low “TOTOX” value).

TOTOX value stands for total oxidation value. The omega 3 fatty acids EPA and DHA from fish oil are highly sensitive to oxidation. This means that they are rapidly affected by contact with oxygen. Oxidised fatty acids are not beneficial to our health. For this reason, a good fish oil supplement has a low TOTOX value. The maximum TOTOX value is set at 26 by the Global Organization for EPA and DHA omega-3.

Caution: A 2024 study published in BMJ Medicine suggests that high-dose use of fish oil may contribute to atrial fibrillation and stroke among the general population.

We recommend taking a maximum of 1 gram of omega-3 per day. Higher amounts could be risky, because EPA and DHA are both polyunsaturated fats (PUFAs) and, like linoleic acid (LA), are susceptible to oxidation and the production of dangerous aldehyde metabolites.

Related: Krill-sourced Fish Oil and Omega-3

4. Vitamin C, E and Selenium

Ascorbic acid, commonly known as vitamin C, is an essential water-soluble vitamin that humans are unable to synthesize endogenously, and must therefore obtain from dietary sources.

PubMed has indexed more than 3,000 research studies on vitamin C and cancer and more than 5,000 studies on vitamin E and cancer. United States Preventive Services Task Force has recommended the use of Vitamin C and E supplementation for cancer prevention (J Oncol Pharm Pract 2024).

Prevention

Best Evidence: An umbrella review* (Xu 2022) to assess the existing systematic reviews and meta-analyses for the association between vitamin C intake and multiple health outcomes; showed that vitamin C intake was associated with reduced risk of all-cause mortality, cardiovascular disease (CVD), oesophageal cancer, gastric cancer, cervical cancer and lung cancer with an increment of 50–100 mg per day.

Beneficial associations were also identified for respiratory, neurological, ophthalmologic, musculoskeletal, renal and dental outcomes. A total of 76 meta-analyses (51 papers) of randomised controlled trials and observational studies with 63 unique health outcomes were identified. Harmful associations were found for breast cancer and kidney stones for vitamin C supplement intake. 

*Umbrella review: An umbrella review, or a review of reviews, is a systematic review that only considers other systematic reviews as an eligible study type for inclusion. An umbrella review compiles evidence from multiple existing reviews and is one of the highest levels of evidence.

2022 - Obese women who took vitamin C and B6 at amounts that exceeded the recommended daily intake levels were associated with a lower risk of breast cancer, according to a five-year long South Korean cohort study. 40,432 women without a history of cancer at baseline were included in this study.

2022 - A meta-analysis to review the association between vitamins and brain cancer showed that intake of vitamin C, β-carotene, and folate can reduce the risk of brain cancer, while high serum α-tocopherol (vitamin E) concentration also has a protective effect on brain cancer.

A 2017 meta-analysis of 11 studies concluded that patients with lower concentrations of serum vitamin E (the vitamin E level in your blood) had a higher risk for colorectal cancer.

Caution: However, the Selenium and Vitamin E Cancer Prevention Trial (SELECT) found that vitamin E taken alone increased the risk of prostate cancer. The risk continued even after the men stopped taking vitamin E. Taking selenium with vitamin E or taking selenium alone did not increase the risk of prostate cancer. (JAMA 2011)

Treatment

2023 - A systematic review to evaluate the existing literature on the safety and efficacy of vitamin C, E and selenium supplementation in cancer patients. Twenty-four articles met the inclusion criteria. Of the included studies, nine evaluated selenium, eight evaluated Vitamin C, four evaluated Vitamin E, and three of these studies included a combination of two or more of these agents. Findings were generally favorable among the studies, and adverse effects of supplementation were limited. The review concluded that antioxidant supplements may provide benefits in reducing incidence or severity of treatment-induced side effects with limited risk for adverse effects.

2022 - A systematic review on the effect of vitamins C and E on cancer survival showed improvement of survival and progression rates of cancers by vitamins C and E. However, the authors concluded that more high quality trials with large sample sizes are required to confirm.

Vitamin C is known as an antioxidant, but at high concentrations, vitamin C can kill cancer cells through a pro-oxidant property (Transl Oncol. 2020). This study has also demonstrated that vitamin C treatment with magnesium supplementation provided more effective anticancer therapy than vitamin C treatment alone.

High-dose vitamin C cancer therapy was introduced by Linus Pauling and Ewan Cameron [source]. Clinical demonstration results by Pauling and Cameron showed that intravenous injection of 10 g/day of vitamin C extended the survival time of terminal cancer patients by about 4.2 times. However, results from the Mayo Clinic in 1979 showed that the survival time of vitamin C–treated patients was even shorter than that of the placebo group patients [source]. A significant difference between those two research groups was the route of AA administration: intravenous injection and oral administration, respectively. 

When treating cancer, IV needs to be used because you simply cannot take the high dosages required orally. Doses over 10 to 20 grams of ascorbic acid will cause loose stools when taken orally, but IV administration bypasses the limitation of the gut. It also allows the vitamin C to get directly into the blood to the extracellular fluid, into the tumor microenvironment, to penetrate the tumor and saturate the entirety of the tumor.

To understand the mechanism of AA's (ascorbic acid) anticancer activity, many research groups have treated colon, prostate, leukemia, lymphoma, brain, and stomach cancer cells and chemically or genetically transformed cancer cells with AA and showed cancer growth inhibition and even cancer cell death through hydrogen peroxide–mediated reactive oxygen species (ROS) generation [source]. 

In most cases, the pharmacological concentration of vitamin C required for anticancer effects (EC50 value of 1–10 mM) could only be achieved by intravenous administration. Thus, to apply vitamin C as an anticancer therapy, a high intracellular concentration in cancer cells is critically important (source).

According to the Mayo Clinic (2023):

"More recently, vitamin C given through a vein (intravenously) has been found to have different effects than vitamin C taken in pill form. This has prompted renewed interest in the use of vitamin C as a cancer treatment.

There's still no evidence that vitamin C alone can cure cancer, but researchers are studying whether it might boost the effectiveness of other cancer treatments, such as chemotherapy and radiation therapy, or reduce treatment side effects.

There are still no large, controlled clinical trials that have shown a substantial effect of vitamin C on cancer, but some preliminary studies do suggest there may be a benefit to combining standard treatments with high-dose IV vitamin C."

 

According to the concluding remarks from a 2020 article from the National Cancer Institute:

Vitamin C as a cancer therapy has had a controversial past. What has been intriguing are small clinical trials that suggest some responses, but with no clear rationale for why cancers should respond to vitamin C or a path forward for explaining which patients are most likely to respond. Now a growing number of preclinical studies are showing how high-dose vitamin C might benefit cancer patients. Importantly, these preclinical studies provide a clear rationale and potential biomarkers that may help personalize the therapeutic approach and identify patient populations that are likely to respond to high-dose vitamin C therapy. Since the mechanisms of action of vitamin C are becoming better defined, we can propose vitamin C combinations in a more rational, hypothesis-driven manner. In addition, given the current high financial cost of new cancer drugs, it seems rational to improve the effectiveness of current therapies by studying their clinical interactions with vitamin C. In our view, the implementation of this treatment paradigm could provide benefit to many cancer patients.

Ascorbic acid vs whole food vitamin C?

Synthetic Ascorbic acid is NOT the same as whole food or whole fruit vitamin C. 

If you were to compare the two to a car, vitamin C would be the whole car, fully functional, and the engine is an enzyme called tyrosinase, while ascorbic acid is the car frame, with no moving parts. A car with the engine can take you from one place to another but the car frame alone will not be able to do that.

Whole food vitamin C can also boost your copper level, as vitamin C contains an enzyme called tyrosinase, which has 2 atoms of copper in it. Ascorbic acid is prooxidant, while vitamin C complex is actually an antioxidant. Anything that has copper is going to be antioxidant.

Related: Benefits of Vitamin C in Cancer Treatment

5. Magnesium and Molecular Hydrogen

PubMed has indexed more than 5,000 research studies on magnesium and cancer.

Magnesium and Colorectal Cancer

Several studies have demonstrated an association between high magnesium intake and reduced risk of colorectal cancer (CRC).

An analysis of the prospective, Swedish Mammography Cohort (JAMA 2005), evaluated 61,433 women aged 40 to 75 without a history of cancer for a mean follow-up of 14.8 years. The highest quintile of magnesium intake was associated with a significantly lower risk of CRC compared with the lowest quintile. This benefit was observed for both colon and rectal cancers.

A case-control study evaluated 2204 subjects from the Tennessee Colorectal Polyp Study (2007), which demonstrated that increasing total magnesium intake was significantly associated with decreasing risk of CR.. The highest tertile of dietary magnesium intake (>298 mg/day) was significantly associated with reduced risk of CRC in an age-adjusted model.

A study of 140,601 postmenopausal women from the Women’s Health Initiative (2015) with an mean follow-up of 13 years demonstrated a significant reduction in CRC risk with the highest quintile of total magnesium intake compared with the lowest quintile of magnesium intake. The benefit was driven by colon cancer, with a trend for rectal cancer.

Magnesium and Pancreatic Cancer

A study of 66,806 subjects aged 50 to 76 at baseline from the Vitamins and Lifestyle cohort (Nature 2015) evaluated magnesium intake and the incidence of pancreatic cancer during a mean follow-up of 6.8 years. Subjects with magnesium intake below the recommended dietary allowance were more likely to develop pancreatic cancer, particularly in those whose intake was less than 75% of the recommended dietary allowance. In this study, a 100 mg/day decrease in magnesium intake resulted in a 24% increase in risk of pancreatic cancer.

Magnesium and Vitamin C

A 2020 study demonstrated that vitamin C treatment with magnesium supplementation provided more effective anticancer therapy than vitamin C treatment alone.

Molecular Hydrogen and Cancer

There is little evidence to show that molecular hydrogen can reduce the risk of cancer. 

However, in terms of cancer treatment, studies involving the effects of H2 on cancer were systematically reviewed. More than 600 articles related to molecular hydrogen and cancer were retrieved from Cochrane, PubMed and Google Scholar, and 27 articles were included for this systematic review (2023). 

Based on the authors' analysis, "H2 plays a promising therapeutic role as an independent therapy as well as an adjuvant in combination therapy, resulting in an overall improvement in survivability, quality of life, blood parameters, and tumour reduction."

Although H2 has demonstrated significant anti-cancer effects, the underlying mechanisms have not yet been elucidated. Many studies have shown that H2 therapy can reduce oxidative stress. This, however, contradicts radiation therapy and chemotherapy, in which ROS (Reactive Oxygen Species) are required to induce apoptosis and combat cancer. 

A 2020 study in Japan administered hydrogen therapy to 42 patients with stage-four lung cancer. The researchers found that hydrogen therapy could extend the overall survival of the patients. Specifically, patients receiving hydrogen therapy had a median survival time of 28 months, almost triple the survival time of those undergoing immunotherapy.

Related: Best Molecular Hydrogen Tablets

Note: Most Molecular Hydrogen tablets uses pure elemental magnesium as its carrier and provides you with approximately 80 mg of magnesium per tablet. So, you receive also highly bioavailable magnesium for a healthy brain, muscles, cells, kidneys, and heart.

6. Melatonin

PubMed has indexed more than 3,300 research studies on melatonin and cancer. 

In 1996, Russel Reiter, PhD (one of the World's leading melatonin researchers), published his book on Melatonin, "Melatonin: Breakthrough Discoveries That Can Help You Combat Aging, Boost Your Immune System, Reduce Your Risk of Cancer and Heart Disease, Get a Better Night's Sleep".

Melatonin is one of the most important antioxidant molecules. In the human body — aside from having direct antioxidant effects — it also stimulates the synthesis of glutathione and other important antioxidants like superoxide dismutase and catalase.

Many people are not aware that only 5% of your body’s melatonin — which is also a potent anticancer agent — is produced in your pineal gland. The other 95% is produced inside your mitochondria — provided you get sufficient near infrared exposure which is typically from sun on your bare skin. This is why vitamin D is more than likely a biomarker for sun exposure, which is intricately involved in melatonin production. (source)

The Mediterranean Diet (MD) dietary pattern is also rich in antioxidants, such as melatonin. A systematic review of 31 studies published in Antioxidants (Elena 2023) showed high melatonin contents in MD-related foods, such as tomatoes, olive oil, red wine, beer, nuts, and vegetables. The consumption of specific MD foods increases melatonin levels and improves the antioxidant status in plasma.

Melatonin is also known to play a fundamental role in regulating the sleep-wake rhythm; however, in the last 10 years it has been discovered that it is actually involved in many other biological mechanisms, also playing an important role in the inflammatory, metabolic and neoplastic processes. In fact, the mechanisms by which melatonin performs an anti-tumor effect are many: it has an anti-oxidant effect that protects against DNA damage, acts as a scavenger of reactive oxygen species (which undermine genomic stability), stimulates DNA repair mechanisms, improves the functioning of the mitochondrial respiratory chain, and inhibits mitochondrial mitophagy and telomerase activity (Molecules 2018).

In addition, melatonin increases the expression of the p53 protein, induces its phosphorylation, inhibiting cell proliferation, promotes apoptosis, reduces the levels of the vascular endothelial growth factor and endothelin-1, fundamental for tumor growth and metastasis formation, reduces inflammatory processes and cell migration (Molecules 2018).

Reduction of melatonin production has also been seen in some types of cancer (breast and prostate) (Mogavero 2021).

Melatonin for Cancer Patients

2022 - An umbrella review from 111 different meta-analyses based on randomized controlled trials (Pharmacological Research 2022):

"Survival at one year (P < 0.005) significantly increased with cancer patients."

2020 - A case series of 14 advanced cancer patients (Trends in Oncology 2020), treated with high dose (1,000 mg/day) of melatonin; achieved a disease control of 54% of the patients:

"Moreover, this preliminary study may also suggest that high dose melatonin has no toxicity in cancer patients with poor clinical status, as well as in healthy subjects."

2005 - A systematic review of 10 randomized controlled trials (J Pineal Res 2005):

"All trials included solid tumor cancers. All trials were conducted at the same hospital network, and were unblinded. Melatonin reduced the risk of death at 1 yr (relative risk: 0.66). Effects were consistent across melatonin dose, and type of cancer. No severe adverse events were reported. The substantial reduction in risk of death, low adverse events reported and low costs related to this intervention suggest great potential for melatonin in treating cancer."

Just be careful, though, as using high-dose melatonin long term could be a prescription for disaster. This is because doses of over 5 to 10 mg are likely to draw out heavy metals like mercury and unless you are on a good detoxification program and using sauna regularly these heavy metals could cause biological damage.

Related: What You Need to Know About Melatonin

7. Green Tea (EGCG)

PubMed has indexed more than 2,000 research studies on EGCG and cancer.

Green tea also contains chemicals called polyphenols that have antioxidant, anti-inflammatory properties and anti-angiogenic properties, and the catechins in green tea polyphenols show very strong anti-angiogenic properties.

Epigallocatechin 3-gallate (EGCG), the active compound in green tea, is synthesized from epicatechin and gallic acid, has garnered considerable attention in the scientific community due to its multifaceted biological and pharmacological properties. These include its anti-oxidant, anti-inflammatory, anti-angiogenic, anti-proliferative, pro-apoptotic, and anti-metastatic functions. 

The Minnesota Green Tea Trial (MGTT. 2015) is the largest and longest double-blind, placebo-controlled, randomized intervention study that specifically evaluated the effects of oral GTE (green tea extract) containing defined quantities of EGCG on established biomarkers of breast cancer risk.

They randomized and stratified 1075 healthy postmenopausal women at high risk of breast cancer according to their breast tissue density and catechol-O-methyltransferase genotypes and divided them into two groups: 537 placebo and 538 green tea groups. Green tea group participants took 4 capsules that contained 843 mg EGCG, whereas the placebo group took capsules without green tea extracts.

Researchers measured changes in percent mammographic density, circulating endogenous sex hormones, and proteins of the insulin-like growth factor axis. Their results showed that supplementation with green tea extract could modify and reduce mammographic density (MD) and protect against breast cancer, even though it was only significant in younger women (50–55 years) and had no effect in older women (R), an age-dependent effect similar to those of tamoxifen.

According to a 2018 review, EGCG and green tea extracts may help prevent or delay cancer onset, cancer recurrence, and secondary growths from cancer.

However, the National Center for Complementary and Integrative Health (NCCIH) state that studies of green tea and cancer in humans have so far produced inconsistent results.

Several epidemiological studies (2011) have reported that the consumption of green tea may decrease cancer risk. Studies have also confirmed numerous health benefits of green tea including prevention of cancer (R, R) and cardiovascular disease, as well as anti-inflammatory, antioxidant, antiarthritic, antibacterial, and antiviral effects. (R, R, R, R).

Given these promising insights, a phase I clinical trial (NCT00516243) has been initiated that targets women with hormone receptor-negative stages I-III breast cancer and aims to explore the safety and effectiveness of EGCG. Concurrently, several clinical trials for CRC (NCT02321969 and NCT01360320) are also in progress. However, while these studies are promising, the potential therapeutic application of EGCG in cancer treatment is still restricted by its limited bioavailability.

If you have cancer, consider drinking up to 3 cups of green tea per day to experience the benefits. Green tea pills are also available, but may be too concentrated. Some studies show health benefits in people who drink as little as one cup per day, while other studies deem five or more cups per day to be optimal (Source, Source).

8. Quercetin and Cancer

Quercetin, a potent flavonoid, is abundant in various plants, fruits, and vegetables, predominantly in glycoside forms found in onions, apples, blueberries, and broccoli. PubMed has indexed more than 4,000 research studies on quercetin and cancer. The safety and potential usefulness of quercetin for the prevention and treatment of cancer have been documented in both animal experiments.

One of the most promising avenues for quercetin lies in its potential as a senotherapeutic agent.

A paper published in August 2022 in Nutrition Research analyzed the pro-apoptotic effect that quercetin has on aging cells. The paper reviewed preclinical and early phase data using quercetin as a senolytic agent and found the data showed it was effective in “preventing or alleviating cancer formation.”

The authors reviewed the importance of cellular aging in the development of cancer cells and the effect that quercetin may have on the suppression of cancer cell proliferation. 

Cellular senescence is a dynamic and multi-step process that is associated with alterations in metabolic activity and gene expression. This can compromise tissue regeneration and contribute to aging. On the other hand, by removing senescent cells, age-related dysfunction can be attenuated and potentially extend the lifespan.

Quercetin was found to promote senescence in glioma cells by inhibiting the activity of HDACs. Moreover, in HepG2 liver cancer cells, quercetin was shown to reactivate P53, thereby inhibiting RNA degradation and protein ubiquitination, leading to the upregulation of P21 expression and concurrent downregulation of cyclin D1, a crucial player in cell cycle arrest (source). 

Thus, quercetin stands out as a potent tool to induce senescence in cancer cells. In the burgeoning field of senolytic treatments, combining quercetin with other agents has also shown promise in efficiently targeting senescent cells.

 

In addition, pre-treatment with quercetin protected against DOX (doxorubicin)-induced normal cell senescence by reducing the number of senescent cells and suppressing the release of SASP factors (source).

The ability of cancer cells to exploit senescence as a defense mechanism against therapies necessitates innovative approaches. 

Repurposing quercetin as an oncological drug has emerged as a strategic solution, as evidenced by a Phase II clinical trial that combined dasatinib and quercetin for the treatment of head and neck squamous cell carcinoma (NCT05724329). 

However, the broader application of quercetin in oncology has several challenges, and issues such as its limited bioavailability, instability, and lack of precise tumor targeting need to be addressed. Thus, novel strategies that augment the bioavailability of quercetin using lipid nanoparticles and chitosan nanoparticles have been developed. For example, a recent Phase II clinical trial assessed the therapeutic efficacy of both quercetin and its nanoparticle variant against oral squamous cell carcinoma cell lines (NCT05456022). 

According to Mount Sinai, quercetin should be used with caution as it may interact with certain antibiotics by reducing the effectiveness of the drug. It may also enhance the effect of some blood thinners, which can increase your risk of bleeding. In addition to these, it may interact with corticosteroids, digoxin, cyclosporine and fluoroquinolones.

9. Zinc and Cancer

PubMed has indexed more than 20,000 research studies on zinc and cancer.

Given the important role of zinc in a wide range of enzymatic reactions and physiological processes, zinc deficiency has been identified in a variety of diseases, notably cancer. In recent years, multiple meta-analyses and reviews looking at zinc levels in individual cancer types have been published, as have a plethora of primary studies demonstrating a link between low zinc levels and specific types of cancer.

In a 2023 review, the authors summarize recent evidence implicating low zinc concentrations in serum or tissues as a characteristic in a wide range of cancers.

On the basis of the correlation between low zinc levels and poor cancer outcomes, many authors have speculated that zinc supplementation could be used to reduce the risk of developing cancer. A retrospective analysis published by Hosui et al. in 2018 reported that zinc supplementation appears to maintain liver function and decrease the risk of developing hepatocellular carcinoma. A more recent study by the same group found that oral zinc supplementation decreased the risk of hepatocellular carcinoma development in patients who received direct-acting antivirals to eradicate HCV [Hosui et al. 2021]. Valenzano et al. in 2021 also reported that in Barrett’s esophagus, administration of zinc gluconate resulted in the upregulation of several tumor-suppressive miRNAs and downregulation of inflammation-inducing proteins. Additionally, a 2022 mini-review by Iqbal et al. noted limited evidence for a correlation between high dietary intake of zinc and a reduced risk of breast cancer, suggesting that dietary supplementation could decrease the chance of developing this malignancy. These preliminary studies suggest that there could be potential for using zinc supplementation in the clinical setting to help prevent cancer development.

The extensive evidence demonstrating the prevalence of zinc deficiency in a wide range of cancer types suggests that zinc deficiency should be considered a relatively widespread feature of multiple cancers. While research regarding the potential clinical utility of testing zinc levels in patients with or at risk of developing cancer is still preliminary, the data suggest that zinc deficiency may be a potential biomarker for identifying patients at risk of developing cancer, predicting outcomes in patients with cancer, and even as a preventive or adjunctive treatment for cancer.

10. Garlic (Allicin) and Onion

PubMed has indexed more than 1,200 research studies on garlic and cancer. Garlic and onions belong to the Allium genus of plants.

2023 - A randomized controlled trial (RCT) on garlic and gastric cancer (GC), published in January 2023, found a significant reduction in the risk of developing GC with increasing dietary intake of allium vegetables, particularly garlic vegetables. 

The study was conducted on the basis of the Shandong Intervention Trial, a randomized, placebo-controlled, factorial-designed trial (1995-2003) in a well-recognized high-risk area for GC in China. Participants were continuously followed up to December 2017 for 22.3 y (1995-2017). A total of 3,229 subjects were included.

2020 - A meta-analysis of 11 studies, published in January 2020, did find evidence that garlic could reduce the risk of ColoRectal Cancer. 

Another study published in the Asia Pacific Journal of Clinical Oncology (2019) revealed the odds of getting ColoRectal Cancer were 79% lower in those who a diet high in allium vegetables, which include garlic, leeks and onions.

One study of 543,220 participants found that those who ate lots of Allium vegetables, such as garlic, onions, leeks and shallots, had a lower risk of stomach cancer than those who rarely consumed them (Source).

A study of 471 men showed that a higher intake of garlic was associated with a reduced risk of prostate cancer (Source).

Based on these findings, including 2–5 grams (approximately one clove) of fresh garlic into your diet per day can help you take advantage of its health-promoting properties.

Garlic is a great choice when it comes to giving your body a little extra protection. To reap the benefits of garlic, you should eat one clove per day, or 300 to 1,000 milligrams (mg)Trusted Source of garlic extract.

The active component in garlic is allicin, a compound that has been shown to kill off cancer cells in multiple test-tube studies (Source, Source, Source).

There is evidence demonstrating garlic can kill cancer cells in vitro. Several studies have analyzed the effects that dietary garlic may have on the development of colorectal cancer. 

Several clinical studies have found an association between garlic intake and a lower risk of certain types of cancer.

Despite the promising results showing an association between garlic and a reduced risk of cancer, more studies are needed to examine whether other factors play a role.

Related: Garlic, the ‘King of Cancer Prevention’

11. Vitamin B2 and B3

Riboflavin (Vitamin B2)

According to the International Journal of Molecular Science 2020 study, riboflavin may be associated with a reduced risk of some cancers. 

A 15-year prospective study (2012) of 41,514 individuals in the Melbourne Collaborative Cohort Study found that current smokers with higher dietary riboflavin intake (2.5 milligrams per day on average) had a significantly lower risk of lung cancer, while this inverse association was not observed in former or never smokers.

Niacinamide (Vitamin B3)

Clinical trials show that taking 500 milligrams (mg) of niacinamide twice daily significantly reduce the incidence of NMSCs (non-melanoma skin cancers) in high-risk individuals. This news was particularly encouraging for those with a history of skin cancer. However, while many studies for skin cancer prevention use 500-mg doses, caution is warranted.

Niacinamide at a dose of 50 mg three times per day is a better dose and will provide the fuel for the rate limiting enzyme for NAD+, NAMPT (NicotinAMide PhosphoribosylTransferase). We recommend getting niacinamide in powder form because the lowest available dose in most supplements is 500 mg, and that will decrease NAD+ due to negative feedback on NAMPT, which is the opposite of what you’re looking for.

Other research has shown a beneficial role of niacinamide intake specifically for SCC (squamous cell carcinoma) risk reduction. In one large-scale study involving the Nurses' Health Study and the Health Professionals Follow-up Study, researchers found that total niacin intake was inversely associated with SCC risk. The pooled hazard ratio was 0.84, suggesting a 16% lower risk of SCC for those with higher niacin intake.

Read more: Niacinamide: The Best Supplement to Prevent Skin Cancer

12. Probiotics and Gut Microbes

Not only have gut bacteria been shown to influence gene expression,(R, R) turning some genes on and others off, research (R) published in 2018 found gut microbes actually control antitumor immune responses in your liver, and that antibiotics can alter the composition of immune cells in your liver, triggering tumor growth.

Harvard Medical School researchers have identified the specific population of gut microbes that modulates both localized and systemic immune response to ward off viral invaders.

Certain gut bacteria also promote inflammation, which is an underlying factor in virtually all cancers, whereas other bacteria quell it. The presence of certain gut bacteria has even been shown to boost the patient's response to anticancer drugs. (Nature 2018)

One way in which gut bacteria improve the effectiveness of cancer treatment is by activating your immune system and allowing it to function more efficiently. Researchers have actually found that when these specific microbes are absent, certain anticancer drugs may not work at all.

Can Antioxidant Supplements help Prevent Cancer?

To update its 2014 recommendation, the US Preventive Services Task Force (USPSTF) commissioned a review of the evidence on the efficacy of supplementation with single nutrients, functionally related nutrient pairs, or multivitamins for reducing the risk of cardiovascular disease, cancer, and mortality in the general adult population, as well as the harms of supplementation. 

According to the recommendation, the USPSTF recommends against the use of beta carotene or vitamin E supplements for the prevention of cardiovascular disease or cancer. (JAMA 2022)

Many observational studies, including case–control studies and cohort studies, have been conducted to investigate whether the use of dietary antioxidant supplements is associated with reduced risks of cancer in humans. Overall, these studies have yielded mixed results (5). Because observational studies cannot adequately control for biases that might influence study outcomes, the results of any individual observational study must be viewed with caution.

Randomized controlled clinical trials, however, lack most of the biases that limit the reliability of observational studies. Therefore, randomized trials are considered to provide the strongest and most reliable evidence of the benefit and/or harm of a health-related intervention. To date, nine randomized controlled trials of dietary antioxidant supplements for cancer prevention have been conducted worldwide. Many of the trials were sponsored by the National Cancer Institute. The results of these nine trials are summarized here. 

 

Overall, these nine randomized controlled clinical trials did not provide evidence that dietary antioxidant supplements are beneficial in primary cancer prevention. (National Cancer Institute 2017)

Further, some studies have found that high-dose supplements containing nutrients such as beta-carotene and vitamins A and E can actually increase the risk of some cancers. (American Cancer Society 2020)

It is possible that the lack of benefit in clinical studies can be explained by differences in the effects of the tested antioxidants when they are consumed as purified chemicals as opposed to when they are consumed in foods, which contain complex mixtures of antioxidants, vitamins, and minerals (PubMed 2010).

Causes of Cancer

Cancer is daunting in the breadth and scope of its diversity, spanning genetics, cell and tissue biology, pathology, and response to therapy. Ever more powerful experimental and computational tools and technologies are providing an avalanche of “big data” about the myriad manifestations of the diseases that cancer encompasses. 

The integrative concept embodied in the hallmarks of cancer (Cancer Discov 2022) is helping to distill this complexity into an increasingly logical science, and the provisional new dimensions presented in this perspective may add value to that endeavor, to more fully understand mechanisms of cancer development and malignant progression, and apply that knowledge to cancer medicine.

The Hallmarks of Cancer were proposed as a set of functional capabilities acquired by human cells as they make their way from normalcy to cancer states.

Biological Changes and Acquired Capabilities (Cell 2000):

1. sustaining proliferative signaling, 
2. evading growth suppressors, 
3. resisting cell death, 
4. enabling replicative immortality, 
5. inducing angiogenesis, and 
6. activating invasion and metastasis.

Emerging Hallmarks (Cell 2011):

1. deregulating cellular energetics
2. avoiding immune destruction

Enabling characteristics (Cell 2011)::

1. Genome instability and mutation
2. Tumor promoting inflammation

Four new hallmarks (Cancer Discov 2022):

1. unlocking phenotypic plasticity,
2. non-mutational epigenetic reprogramming,
3. polymorphic microbiomes
4. senescent cells.

 

Diet and Cancer Prevention

AACR Cancer Progress Report 2023

Does eating healthy prevent cancer? According to the American Cancer Society (2020),  a diet rich in vegetables, fruits, and other plant-based foods may reduce the risk of cancer.

A 2024 umbrella review* (BMJ) of the literature confirmed what multiple studies have shown — the higher your intake of ultraprocessed food, the higher your risk of adverse health outcomes. The analysis, which included 45 unique pooled analyses and 9,888,373 participants, found direct associations between 32 health parameters and exposure to ultra processed food, including metabolic dysfunction, cancer, mental, respiratory, cardiovascular and gastrointestinal issues, as well as all-cause mortality.

*Umbrella review: An umbrella review, or a review of reviews, is a systematic review that only considers other systematic reviews as an eligible study type for inclusion. An umbrella review compiles evidence from multiple existing reviews and is one of the strongest and highest levels of evidence.

Another umbrella review*, published in May 2024 in PLOS One, evaluated 48 previous reviews and meta-analyses published between 2000 and 2023 and concluded that vegetarian or vegan diets “significantly reduce the risk” of ischemic heart disease, gastrointestinal cancer, and prostate cancer, as well as associated mortality.

Caution: What are the nutrients of concern for vegetarians and vegans? Vitamin B12 and K2. Anybody who is eating a vegan diet or a vegetarian diet or just a mostly plant-based diet should be taking vitamin B12 and K2 supplements. Vitamin B12 is only found in significant amounts in animal products and fortified foods, and a deficiency can cause anemia, mood changes, or permanent neurological damage. Plant-based diets may also be low in vitamin D, omega-3 fatty acids, and minerals like iodine, selenium, iron, and zinc. 

Evidence from another umbrella review (BMJ 2023) of more than 8,000 studies supports the limiting dietary sugar recommendation.

A 2023 umbrella review (more than 100 studies analysed) of the literature indicated that a high intake of dietary fiber is associated with a reduced risk of several types of cancer, including esophageal, gastric, colon, rectal, colorectal adenoma, breast, endometrial, ovarian, renal cell, prostate, and pancreatic cancers. Conclusion: Dietary fiber intake has different protective effects on different cancers.

According to a 2019 Lancet publication, risk reduction associated with a range of critical outcomes was greatest when daily intake of dietary fibre was between 25 g and 29 g.

A 2018 study published by Cambridge University Press found an association between higher intakes of sugar-sweetened soft drinks and an increased risk of obesity-related cancers. Research published in the American Journal of Clinical Nutrition in 2020 concluded that sugars may be a risk factor for cancer, breast in particular. Cancer cells are ravenous for sugar, consuming it at a rate 200 times that of normal cells.

A consensus on the best dietary approach for reducing cancer risk has yet to be determined, and further research is needed. However, the findings of the Cell study on MGO (2024) support reducing sugar intake as a means to mitigate cancer risk. 

In 2023, a study published in Cell determined that a ketogenic diet may be an effective nutritional intervention for cancer patients as it helped slow the growth of cancer cells in mice—while a review published in JAMA Oncology in 2022 found that the current evidence available supports a plant-enriched diet for reducing cancer risk.

A large study that involved 79,952 US-based men found that those who ate the largest amounts of healthy plant-based foods had a 22% lower risk of bowel cancer compared with those who ate the least. The team suggested that the link is clearer for men, who have an overall higher risk of bowel cancer. Their findings were published in the journal BMC Medicine (Nov 2022).

The ketogenic diet is a low-carbohydrate but contains fiber, cruciferous vegetables, high-healthy fat, and protein diet that forces the body to rely on ketones instead of glucose as a predominant energy source. It has shown potential in preclinical and early clinical studies for brain cancer treatment. By altering the metabolism of cancer cells, the ketogenic diet may inhibit tumor growth and enhance the effectiveness of other therapies (Neurology 2021).

Another 2017 review of 24 human studies concluded that the probability of achieving an anti-tumor effect seems greater than that of causing serious side effects when offering Keto Diets to cancer patients.

Intermittent fasting or prolonged fasting refers to periods of restricted calorie intake or complete food avoidance. Like the Ketogenic diet, fasting triggers the use of ketones as the predominant energy source and may sensitize cancer cells to treatments and potentially slow down tumor growth. Fasting-induced metabolic changes may also favor the protection of normal tissues from therapy side effects and improve tolerance and quality of life impacts to care. 

Thomas Seyfried said that by keeping the mitochondria in cells healthy, people are less likely to get cancer. He said this can be achieved through a certain period of fasting (drinking only water), a low-carb diet, and exercise.

Dr. Graham Simpson, medical director of Opt Health stresses the importance of real food and healthy macronutrients with a low-carb intake for the health of our cells. “The mitochondria is the most important signaling molecule and energy-producing organelle that we have in our body. [Eat] lots of vegetables, healthy proteins and healthy fats, fish, eggs, yogurt.” He continues, “Lots of green, above-ground vegetables, some fruits, everything that is naturally grown and is not processed.”

Although eating healthy foods can't ensure cancer prevention, it might reduce the risk. Consider the following in general:

• Eat plenty of fruits and vegetables. Basing your diet on fruits, vegetables and other foods from plant sources — such as whole grains and beans. Eat lighter and leaner by choosing fewer high-calorie foods. Limit refined sugars and fat from animal sources.
• Drink alcohol only in moderation, if at all. Alcohol increases the risk of various types of cancer, including cancer of the breast, colon, lung, kidney and liver. Drinking more increases the risk.
• Limit processed meats. Eating processed meat often can slightly increase the risk of certain types of cancer. This news comes from a report from the International Agency for Research on Cancer, the cancer agency of the World Health Organization.

Another study conducted by Johns Hopkins University (2020) with a median follow-up of 11 years found that intensive lifestyle intervention (reduced caloric intake and increased physical activity) can reduce the risk of obesity-related cancers (including esophageal cancer, colon cancer, rectal cancer, kidney cancer, pancreatic cancer, stomach cancer, liver cancer, gallbladder cancer, thyroid cancer, uterine cancer, ovarian cancer, postmenopausal breast cancer, and multiple myeloma) by 16 percent. The researchers believe that this is due to the lifestyle intervention that led to the weight loss of the subjects.

Editor's Note: Please remember that reducing your risk of cancer doesn’t simply depend on one stand alone strategy, nutrient or supplement. Even if you zealously consume various supplements, you can still fall victim to cancer if you fail to address your other risk factors.

 

The Mediterranean-DASH diet

People who eat a Mediterranean diet that includes extra-virgin olive oil and mixed nuts might have a reduced risk of breast cancer. The Mediterranean diet focuses mostly on plant-based foods, such as fruits and vegetables, whole grains, legumes and nuts. People who follow the Mediterranean diet choose healthy fats, such as olive oil, over butter. They eat fish instead of red meat.

A meta-analysis of 45 studies published in 2022 found that people who consume olive oil daily have a 31 percent lower risk of any cancer compared to those who consume olive oil less frequently.

The Mediterranean-DASH (MIND) diet combines elements of the Mediterranean diet and the Dietary Approaches to Stop Hypertension (DASH) diet. Here’s what we know:

• MIND Diet and Breast Cancer Risk: A 2022 study investigated the association between the MIND diet and breast cancer risk among Tehranian adult women. The study included 134 women with recently diagnosed breast cancer (confirmed histologically) and 272 women of the same age as controls. Results showed that individuals in the highest tertile of the MIND diet had a 45% lower risk of breast cancer compared to those in the lowest tertile.
• Mediterranean Diet and Cancer: The Mediterranean diet is characterized by high consumption of vegetables, fruits, whole grains, and olive oil, while limiting meat, sweets, and saturated fat. Research suggests that the Mediterranean diet is linked to lower risks of cancer and may help alleviate symptoms and imbalances common among people with cancer. 
• The abundance of antioxidants and cancer-fighting phytochemicals in this diet contributes to its potential protective effects against cancer (American Institute of Cancer Research 2013).

Halma et al. 2023

Healthy and unhealthy oils 

Avoid seed oils high in linoleic acid. Refined vegetable oils like canola oil, corn oil, soybean oil, and cottonseed oil are high in omega-6 fatty acids, which have been linked with an increased risk of cancer, as well as creating higher levels of oxidative stress in the body. (source, source)

Linoleic acid is an Omega-6 fatty acid that our bodies require in small amounts. Unfortunately, many people eat up to 10 times the desired amount of linoleic acid, because of excess consumption of foods made with seed oils. Too much linoleic acid is associated with inflammation, obesity, heart disease, and other unfavorable conditions. Therefore, avoid:

• Soybean oil 

• Corn oil 

• Cottonseed oil 

• Sunflower oil 

• Sesame oil 

• Grapeseed oil 

• Safflower oil 

• Margarine 

• Rice bran oil 

Instead, opt for healthy oils and fats such as the ones listed below. Use only high-quality products and check production and expiration dates. 

• Olive oil (oleic acid, Omega-9 monounsaturated fatty acids); never heat olive oil to the point where it produces smoke. 

• Avocado oil (oleic acid, Omega-9 monounsaturated fatty acids) 

• Coconut oil (medium chain fatty acid) 

• Flaxseed oil (alpha-linolenic acid, ALA Omega-3) 

• Walnut and Pecan oils; should be refrigerated to avoid spoilage 

• Butter (saturated fat) 

Note: This article is part of the Unveiling the Science Behind Cancer, Diet and Supplements series. Check out part 2: Can Diet and Lifestyle influence your Risk of getting Cancer? 1,000+ Studies Analyzed (2024)

Don't use tobacco

Smoking is a major cause of cancer. Cigarette smoking topped the charts as the leading risk factor, contributing to nearly 20 percent of all cancer cases and close to 30 percent of cancer deaths. Smoking comprised 56 percent of potentially preventable cancers in men and almost 40 percent of those in women. (Journal of the American Cancer Society 2024)

Journal of the American Cancer Society 2024

Smoking has been linked to many types of cancer, including cancer of the lung, mouth, throat, voice box, pancreas, bladder, cervix and kidney. Even being around secondhand smoke might increase the risk of lung cancer.

But it's not only smoking that's harmful. Chewing tobacco has been linked to cancer of the mouth, throat and pancreas.

Staying away from tobacco — or deciding to stop using it — is an important way to help prevent cancer. For help quitting tobacco, ask a health care provider about stop-smoking products and other ways of quitting.

Maintain a healthy weight and be physically active

Being at a healthy weight might lower the risk of some types of cancer. These include cancer of the breast, prostate, lung, colon and kidney.

Physical activity counts too. Besides helping control weight, physical activity on its own might lower the risk of breast cancer and colon cancer.

Doing any amount of physical activity benefits health. But for the most benefit, strive for at least 150 minutes a week of moderate aerobic activity or 75 minutes a week of hard aerobic activity.

You can combine moderate and hard activity. As a general goal, include at least 30 minutes of physical activity in your daily routine. More is better.

Studies Confirm Importance of Strength Training in Moderation

Best evidence: A systematic review and meta-analysis of 16 studies published in the British Journal of Sports Medicine in 2022.

Muscle-strengthening activities were associated with a 10% to 17% lower risk of cardiovascular disease (CVD), total cancer incidence, Type 2 diabetes and all-cause mortality*. As in O’Keefe’s study, this review found a J-shaped association, with a maximum risk reduction of all-cause mortality, CVD and cancer (10 % to 20%) being observed at a dose of 30 to 60 minutes per week.

*Note: "Death from anything" may be a clearer term for the layperson as opposed to 'All-cause mortality'. This is one of the best measures for the factors that increase the risk of what eventually and most likely will take someone's life.

After 60 minutes, the benefits of strength training started to diminish, and above 140 minutes per week, it was associated with an increased risk of all-cause mortality. 

Another 2022 systematic review published in the American Journal of Preventive Medicine (AJPM) found that:

“Compared with undertaking no resistance training, undertaking any amount of resistance training reduced the risk of all-cause mortality by 15% ... cardiovascular disease mortality by 19% ... and cancer mortality by 14% ...

A dose-response meta-analysis of 4 studies suggested a nonlinear relationship between resistance training and the risk of all-cause mortality. A maximum risk reduction of 27% was observed at around 60 minutes per week of resistance training ... Mortality risk reductions diminished at higher volumes.”

Fasting and Cancer

Fasting may help reduce obesity-associated cancers. “There’s a lot of obesity-associated cancers,” said Dr. Jason Fung, a nephrologist and fasting expert. “There’s about 13 cancers that are well accepted that they are associated with obesity; fasting might help decrease that.”

Fasting can potentially starve cancer cells. When fasting, the body uses fats and produces ketones for energy. Cancer cells rely heavily on glucose, making them less efficient at using ketones.

Additionally, fasting reduces insulin levels. Elevated insulin levels are linked to an increased risk of breast, prostate, and colorectal cancers.

Intermittent fasting may protect against liver inflammation and even liver cancer, a 2024 study has found. The study, conducted at the German Cancer Research Center and the University of Tübingen and published in the journal Cell Metabolism, aimed to understand more about how intermittent fasting can affect the liver. The researchers found that intermittent fasting can halt the progression of non-alcoholic fatty liver disease (NAFLD), a precursor to chronic liver inflammation and liver cancer. 

Although the study is promising, the researchers acknowledge that because the study was conducted on mice, there is no way to know definitively whether the intermittent fasting regimen would produce the same results in humans.

It is important to remember that intermittent fasting is not the best dietary choice for everyone and can even have dangerous consequences for people with certain health conditions.
 

Alcohol

Drink alcohol only in moderation, if at all. Alcohol increases the risk of various types of cancer, including cancer of the breast, colon, lung, kidney and liver. Drinking more increases the risk.

On July 11, 2024, CA: A Cancer Journal for Clinicians published a study investigating modifiable risk factors that can lead to cancer. The top examples they identified include cigarette smoking and obesity. Another leading modifiable factor was alcohol consumption.

A 2021 umbrella review (Nature) of the literature concluded that Alcohol consumption is positively associated with risk of postmenopausal breast, colorectal, esophageal, head & neck and liver cancer.

Related: Best Liver Support Supplements 2024

Gut Microbes and Probiotics

Not only have gut bacteria been shown to influence gene expression (R, R), turning some genes on and others off, research (R) published in 2018 found gut microbes actually control antitumor immune responses in your liver, and that antibiotics can alter the composition of immune cells in your liver, triggering tumor growth.

Harvard Medical School researchers have identified the specific population of gut microbes that modulates both localized and systemic immune response to ward off viral invaders.

Certain gut bacteria also promote inflammation, which is an underlying factor in virtually all cancers, whereas other bacteria quell it. The presence of certain gut bacteria has even been shown to boost the patient's response to anticancer drugs. (Nature 2018)

One way in which gut bacteria improve the effectiveness of cancer treatment is by activating your immune system and allowing it to function more efficiently. Researchers have actually found that when these specific microbes are absent, certain anticancer drugs may not work at all.

Avoid risky behaviors

Another effective cancer prevention tactic is to avoid risky behaviors that can lead to infections that, in turn, might increase the risk of cancer. For example:

• Practice safe sex. Limit the number of sexual partners and use a condom. The greater the number of sexual partners in a lifetime, the greater the chances of getting a sexually transmitted infection, such as HIV or HPV.

  People who have HIV or AIDS have a higher risk of cancer of the anus, liver and lung. HPV is most often associated with cervical cancer, but it might also increase the risk of cancer of the anus, penis, throat, vulva and vagina.

• Don't share needles. Injecting drugs with shared needles can lead to HIV, as well as hepatitis B and hepatitis C — which can increase the risk of liver cancer. If you're concerned about drug misuse or addiction, seek professional help.

Protect yourself from the sun

Skin cancer is one of the most common kinds of cancer and one of the most preventable. Try these tips:

• Avoid midday sun. Stay out of the sun between 10 a.m. and 4 p.m. when the sun's rays are strongest.
• Stay in the shade. When outdoors, stay in the shade as much as possible. Sunglasses and a broad-brimmed hat help too.
• Cover your skin. Wear clothing that covers as much skin as possible. Wear a head cover and sunglasses. Wear bright or dark colors. They reflect more of the sun's harmful rays than do pastels or bleached cotton.
• Don't skimp on sunscreen. Use a broad-spectrum sunscreen with an SPF of at least 30, even on cloudy days. Apply a lot of sunscreen. Apply again every two hours, or more often after swimming or sweating.
• Don't use tanning beds or sunlamps. These can do as much harm as sunlight.

Sleep, Stress and Desk Job

Sleep

Many studies, especially in the last 10 years, have evaluated the association between different types of cancer and different types of sleep disorders (Mogavero 2021). The majority of sleep disorders in patients with cancer are associated with activation of the inflammatory response (Mogavero 2021). 

Circadian rhythm disorders seem to represent a risk factor for gastrointestinal and breast cancer, squamous cell carcinoma, thyroid and prostate cancer (albeit with dubious evidence), lymphomas and chronic myeloid leukemia, not for ovarian cancer. Insomnia represents a risk factor for a wide range of tumors, especially breast, nose, trachea, liver and oral cavity. (Mogavero 2021)

In a 2022 study, the detrimental associations of poor sleep with all-cause and cause-specific mortality risks are exacerbated by low PA (physical activity), suggesting likely synergistic effects. The study supports the need to target both behaviours in research and clinical practice.

A 2023 study indicated that insomnia and nap during the day may be risk factors of PLC (primary liver cancer) and adequate night sleep might keep us away from PLC (primary liver cancer).

A 2021 study, concluded that both unfavorable sleep duration and evening chronotype were associated with increased lung cancer incidence, especially for those with low to moderate genetic risk. These results indicate that sleep behaviors as modifiable risk factors may have potential implications for lung cancer risk.

Another similar study, the authors concluded that they have found robust evidence for effect of sleeplessness on lung cancer risk.

Stress

High stress might be one of the most overlooked factors, especially concerning the long-term impact of being exposed to a stressful job environment.

However, it’s important to understand the role of stress on cancer progression. Scientists know that psychological stress can affect the immune system, the body’s defense against infection and disease (including cancer).

The body responds to stress by releasing stress hormones, such as epinephrine (also called adrenaline) and cortisol (also called hydrocortisone). The body produces these stress hormones to help a person react to a situation with more speed and strength. Stress hormones increase blood pressure, heart rate, and blood sugar levels. Small amounts of stress are believed to be beneficial, but chronic (persisting or progressing over a long period of time) high levels of stress are thought to be harmful.

Stress that is chronic can increase the risk of obesity, heart disease, depression, and various other illnesses. Stress also can lead to unhealthy behaviors, such as overeating, smoking, or abusing drugs or alcohol, that may affect cancer risk.

Some studies have indicated an indirect relationship between stress and certain types of virus-related growths. Evidence from both animal and human studies suggests that chronic stress weakens a person’s immune system, which in turn may affect the incidence of virus-associated cancers, such as Kaposi sarcoma and some lymphomas.

It is difficult to separate stress from other physical or emotional factors when examining cancer risk. For example, certain behaviors, such as smoking and using alcohol, and biological factors, such as growing older, becoming overweight, and having a family history of cancer, are common risk factors for cancer.

Studies have shown that stress might promote cancer indirectly by weakening the immune system's anti-tumor defense or by encouraging new tumor-feeding blood vessels to form. But a study published in The Journal of Clinical Investigation shows that stress hormones, such as adrenaline, can directly support tumor growth and spread.

Desk Job

One of the most important aspects of lifestyle is your job. If you're among the 86% of American workers who work at a desk all day, your job may have an adverse effect on your health. 

Studies have found that those who sat for more than 8 hours a day with no physical activity had a risk of dying similar to the risk posed by obesity and smoking.

A 2009 study found that people who had increased sitting times had higher rates of cancer and overall mortality, even when they got some daily exercise.

The American Cancer Society has also found a link between long periods of inactivity and cancer. The group says that people who spend "prolonged leisure time sitting" — defined as more than 6 hours per day — have a 19% higher rate of death compared to people who sit an average of 3 hours per day. That number includes all causes of death, but it doesn't necessarily mean that sitting directly causes cancer or other diseases, since sick people are also likely to move around less.

Get regular medical care and Health Screening

Doing regular self-exams and having screenings for cancers — such as cancer of the skin, colon, cervix and breast — can raise the chances of finding cancer early. That's when treatment is most likely to succeed. Ask a health care provider about the best cancer screening schedule for you.

Avoid unnecessary exposure to radiation.

Get medical imaging studies only when you need them. (Harvard Health)

Check your home for residential radon, which increases the risk of lung cancer. Protect yourself from ultraviolet radiation in sunlight, which increases the risk of melanomas and other skin cancers. But don't worry about electromagnetic radiation from high-voltage power lines or radiofrequency radiation from microwaves and cell phones. They do not cause cancer.

Avoid exposure to environmental toxins and infections that contribute to cancer

Avoid exposure to industrial and environmental toxins such as asbestos fibers, benzene, aromatic amines, and polychlorinated biphenyls (PCBs). (Harvard Health)

Avoid infections that contribute to cancer, including hepatitis viruses, HIV, and the human papillomavirus. Many are transmitted sexually or through contaminated needles. (Harvard Health)

Caution and Concern

It's important to emphasize caution when it comes to these natural products. It wasn't long ago that, after finding that people who ate a diet rich in foods containing beta-carotene had a lower risk of lung cancer, researchers set out to study the potential effect of supplements of beta-carotene on risk. Unlike the reduced risk seen with dietary beta-carotene, however, beta-carotene in supplement form was associated with an increased risk of developing the disease.

Key Takeaways

The best way to prevent cancer is to utilise a menu of strategies by maintaining good health, like from eating a nutritious fresh whole-food diet with lots of fruits and vegetables, avoid ultra processed foods and a healthy lifestyle with less stress. 

Everyone’s situation is different, however, it is important to arm yourself with medical knowledge that cancer doctors (Oncologists) may simply not give you.

While supplements can be beneficial, they should complement, not replace, these fundamental preventive strategies. Taking supplements as a stand alone strategy cannot replace an unhealthy lifestyle i.e. heavy smoker, alcoholic, a very stressful and non-active lifestyle, overweight and obesity.

While there’s no silver bullet supplement, there are some anti-cancer supplements on the market that may help you keep the disease at bay or stop it from getting worse. Whether you’re living with cancer, a survivor, or just concerned for your health, talk to your doctor to determine the best treatment for you. 

Note: This is part 1 in Unveiling the Science Behind Cancer, Diet and Supplements series. Check out part 2: Can Diet and Lifestyle influence your Risk of getting Cancer? 1,000+ Studies Analyzed (2024)

Read More: This article is part of the Winning the War on Cancer series.

This article is also part of the diet and cancer series. Other popular diet and cancer related articles:

• Top 10 Repurposed Drugs and Metabolic Interventions for Cancer Treatment: Evidence Based (2024)

• Expert Explains Cancer May Be Metabolic Disease, and Shares a Cure

• Gendicine, The First Approved p53 Gene Therapy Product for Cancer: 20 Years Track Record

• Eat These Foods to Starve Cancer Cells to Death

• Best Natural Ways to Anti Aging and Longevity (2024 Edition)

• How Vegetable Oil and Linoleic Acid Wrecks Your Health

For more information on treatment, causes and prevention, screening, and the latest research, check out this comprehensive resource page (by cancer type) from the U.S. National Cancer Institute: https://www.cancer.gov/types.