Do Cancer-Fighting Foods Work?

Research suggests that diet and lifestyle changes can reduce the risk of developing cancer by approximately 40%

It also suggests that a healthy diet can increase the recovery from cancer. However, much of the research about nutrition’s impact on cancer is limited and there is no guarantee that your diet can help protect from cancer developing or to help to cure cancer. Therefore, diet recommendations cannot be recommended from research.

Here, we will uncover what the research says about specific claims related to nutrition and cancer risk. 

Hispanic woman chopping salad greens

 Jamie Grill/Getty Images

Protects Cells From Cancer

Antioxidants are compounds that stop the oxidation process. This effect can be seen in food, like when lemon juice is put on apple slices, the ascorbic acid prevents oxygen from browning the apples as quickly. 

Antioxidants also help within the body by stopping free radicals from oxidizing and damaging cells. It's claimed that having antioxidants can help to protect cells from becoming cancerous and that it can slow the growth of cancer cells.

Research supports this claim that antioxidants have anti-tumor, anti-carcinogenic, and anti-inflammatory effects. It supports that these effects help to treat cancer cell turnover, which slows down cell growth and protects healthy cells from mutating into cancerous cells.

Commonly recommended antioxidants include carotenoids, flavonoids, and other phytochemicals.


Carotenoids are the pigment responsible for the orange, yellow, and red colors in foods. A common carotenoid, beta carotene, is also a precursor to vitamin A. Research has associated the antioxidant effects of this compound with being protective against developing cancer.

Sources of catenoids include:

  • Apricots
  • Carrots
  • Corn
  • Squash
  • Pumpkin
  • Tomatoes
  • Sweet potato
  • Peaches
  • Kale
  • Broccoli


Lycopene is a bright red pigment found in foods. It’s antioxidant effects have been associated with preventing and treating cancer.

Sources of lycopene include:

  • Tomatoes
  • Watermelon
  • Pink grapefruit


Early research suggests the intake of lutein is associated with a decreased risk for developing cancer because it helps to protect cells.

Lutein is found in foods such as:

  • Spinach
  • Kale
  • Yellow Carrots
  • Zucchini
  • Squash
  • Egg Yolks
  • Herbs—dill and chives

Kaempferol and Quercetin

Both kaempferol and quercetin are flavonoids that help to control the activity of cells and protect them from damage from free radicals. Research has associated these with a decreased risk of developing cancer.

Sources of kaempferol include:

  • Kale
  • Beans
  • Tea
  • Spinach
  • Broccoli

Sources of quercetin include:

  • Apples
  • Honey
  • Raspberries
  • Onions
  • Red grapes
  • Green leafy vegetables


Curcumin is the bright yellow chemical found in turmeric and it contributes to most of the health benefits of turmeric. Early research shows this compound has great potential to help prevent and treat cancer, but it can have a poor absorption rate that can limit its effects. More research is needed before curcumin can be fully recommended for cancer treatment.

Curcumin is found in turmeric and can be added to the diet by using this spice in foods or drinks.

Supports Healthy DNA

Folic acid and folate are different forms of a B-vitamin. Folate is naturally occurring in foods and folic acid is an artificial form used to fortify products—like bread and cereals—to increase the intake.

Folate deficiency was first discovered for its importance during pregnancy to prevent neural tube defects. Since then, the importance of folate to support healthy DNA methylation (which helps control gene expression) and DNA synthesis (the process for creating new cells) has been discovered.

Research suggests that folate deficiency can interfere with some DNA pathways leading to less stable DNA and increased risk for some types of cancer. Further research is needed to fully understand the relationship between folate and cancer risk.Caution is needed using artificial folic acid supplementation because, in theory, cancer cells can also benefit from folic acid and several chemotherapy agents inhibit folic acid metabolism.

Sources of folate include:

  • Broccoli
  • Brussels sprouts
  • Leafy green vegetables
  • Peas
  • Chickpeas and kidney beans
  • Grain products fortified with folic acid

Stops Carcinogens From Damaging Cells

Sulforaphane is a phytochemical that, according to research, is a potent chemopreventive compound. It has been related to:

  • Decreasing the occurrence of cancer
  • Suppressing the growth of cancer cells
  • Increasing the death of cancer cells

Research about the role of sulforaphane in cancer suppression is promising, but it is still not clearly understood.

It should also be noted that the study also found sulforaphanes could reduce the effectiveness of other types of chemotherapeutics.

Sulforaphanes are metabolized from glucosinolates that are found in cruciferous vegetables, such as:

  • Broccoli
  • Brussels sprouts
  • Cabbage
  • Cauliflower
  • Arugula
  • Collard greens

Slows Tumor Growth

Proteases have long been associated with increased tumor growth and disease progression. Protease inhibitors have been used to help slow down tumor growth and the progression of cancer. Protease inhibitors are found in medication and some foods. Food sources include:

  • Legumes
  • Whole grains
  • Apples
  • Bananas
  • Pineapples
  • Cabbage
  • Cucumbers
  • Spinach

Phytates and phytic acid in cancer therapy has been researched for decades. Research has associated phytic acid with decreased cell growth and decreased metastasis of tumors.

Phytates can be found in:

  • Seeds
  • Nuts
  • Legumes
  • Whole grains

Kills Cancer Cells

A high fiber diet is associated with better gastrointestinal health because it helps with regularity and is considered protective against multiple diseases.

Dietary fiber is associated with decreased risk for colon cancer because it helps maintain a healthy gut microbiome, stops the growth the cancer cells, and increases cell death for cancer cells. Further research is still needed to fully understand the effects of dietary fiber on cancer because research is still limited in human subjects.

Foods that are high in fiber include

  • Beans
  • Lentils
  • Broccoli
  • Berries
  • Avocados
  • Apples
  • Whole grains

Starves Cancer Cells

There are emerging claims that the ketogenic diet starves cancer cells resulting in tumor suppression and cancer cell death. The Keto diet is high in fat, moderate in protein, and low in carbs. Ketones are produced when the body lacks sufficient carbohydrates for normal metabolism and the body is forced to use less efficient metabolic pathways that result in ketones being produced as a byproduct. 

Research suggests that in certain cancer types, glucose is the primary fuel source for cancer cells; it is unclear though that by just limiting carb intake via the Keto diet cancer cell growth can be reduced without any other interventions. There is still more research needed to understand the possible benefits of the keto diet for cancer treatment and to better assess the risks, such as increased weight loss and muscle wasting.

Reduces Obesity-Related Cancer Risk

In a 2019 study, it was mentioned that obesity may have caused 14% of cancer deaths in men and 20% for women. In the study, it was even suggested that obesity would soon surpass smoking as the most significant preventative factor against cancer.

Both diet and physical activity are important for maintaining a healthy weight. Eating a diet high in fiber from fruits, vegetables, and whole grains along with lean proteins and healthy fats helps with maintaining fullness throughout the day and helps reduce total calorie intake when compared to the typical “Western” diet.

Are Whole Foods Better Than Supplements?

Most of the research around the effects of foods for fighting cancer is still not fully understood. It is likely a combination of all these nutrients that help to reduce the risk for cancer and help with fighting it.

Eating whole foods instead of supplements is recommended because whole foods provide a wider range of nutrients. Many of these contain multiple of these cancer-fighting compounds, whereas supplements are made from isolating or manufacturing these.

How to Best Eat Veggies

How you prepare your vegetables could be affecting how much vitamin, minerals, and phytochemicals you are getting from these nutritious foods. For most vegetables, eating them raw will help the nutrients remain intact. The next best way to eat your vegetables is to try steaming and sautéing them with small amounts of water. This helps to keep water in the vegetables and prevent nutrient losses.

Be careful when boiling vegetables because it is easy to lose a large portion of the phytochemicals into the water. If you’ve ever drained boiled vegetables and noticed a change in the color of the water, that is part of the phytochemicals being lost.

The important thing when cooking vegetables is to try to limit the loss of water and nutrients from the vegetables to receive the full benefits of their nutrients.

A Word From Verywell

There are no foods or diet plans guaranteed to cure cancer or stop it from developing. A healthy diet can help to support your immune system and strengthen your body to fight off illness. Eating a balanced diet full of fruits, vegetables, whole grains, lean proteins, and healthy fats ensures that you are getting a wide variety of vitamins, minerals, and compounds that will help to maintain your health and could help to support the suppression of cancer. 

13 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Rowles JL, Erdman JW. Carotenoids and their role in cancer prevention. Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids. 2020;1865(11):158613. doi:10.1016/j.bbalip.2020.158613

  2. Gholamian-Dehkordi N, Luther T, Asadi-Samani M, Mahmoudian-Sani MR. An overview on natural antioxidants for oxidative stress reduction in cancers; a systematic review. Immunopathol Persa. 2017;3(2):e12. doi:10.15171/ipp.2017.04

  3. Key TJ, Bradbury KE, Perez-Cornago A, Sinha R, Tsilidis KK, Tsugane S. Diet, nutrition, and cancer risk: what do we know and what is the way forward? BMJ. 2020;368. doi:10.1136/bmj.m511

  4. Bayat Mokhtari R, Baluch N, Homayouni TS, et al. The role of Sulforaphane in cancer chemoprevention and health benefits: a mini-review. J Cell Commun Signal. 2018;12(1):91-101. doi:10.1007/s12079-017-0401-y

  5. Imran M, Salehi B, Sharifi-Rad J, et al. Kaempferol: a key emphasis to its anticancer potential. Molecules. 2019;24(12). doi:10.3390/molecules24122277

  6. Giordano A, Tommonaro G. Curcumin and cancer. Nutrients. 2019;11(10). doi:10.3390/nu11102376

  7. Pieroth R, Paver S, Day S, Lammersfeld C. Folate and its impact on cancer risk. Curr Nutr Rep. 2018;7(3):70-84. doi:10.1007/s13668-018-0237-y

  8. Eatemadi A, Aiyelabegan HT, Negahdari B, et al. Role of protease and protease inhibitors in cancer pathogenesis and treatment. Biomed Pharmacother. 2017;86:221-231. doi:10.1016/j.biopha.2016.12.021

  9. Bohn L, Meyer AS, Rasmussen SK. Phytate: impact on environment and human nutrition. A challenge for molecular breeding. J Zhejiang Univ Sci B. 2008;9(3):165-191. doi:10.1631/jzus.B0710640

  10. Zeng H, Lazarova DL, Bordonaro M. Mechanisms linking dietary fiber, gut microbiota and colon cancer prevention. World J Gastrointest Oncol. 2014;6(2):41-51. doi:10.4251/wjgo.v6.i2.41

  11. Allen BG, Bhatia SK, Anderson CM, et al. Ketogenic diets as adjuvant cancer therapy: History and potential mechanism. Redox Biol. 2014;2:963-970. doi:10.1016/j.redox.2014.08.002

  12. Branco AF, Ferreira A, Simões RF, et al. Ketogenic diets: from cancer to mitochondrial diseases and beyond. European Journal of Clinical Investigation. 2016;46(3):285-298. doi:10.1111/eci.12591

  13. Avgerinos KI, Spyrou N, Mantzoros CS, Dalamaga M. Obesity and cancer risk: Emerging biological mechanisms and perspectives. Metabolism. 2019;92:121-135. doi:10.1016/j.metabol.2018.11.001

By Ashley Braun, MPH, RD
Ashley Braun, MPH, RD, is a registered dietitian and public health professional with over 5 years of experience educating people on health-related topics using evidence-based information. Her experience includes educating on a wide range of conditions, including diabetes, heart disease, HIV, neurological conditions, and more.