There is no specific food that can protect anyone from cancer completely. The term cancer-fighting foods refer to diets and foods that have the potentil to lower the risk of having or increasing cancer if a person adds them to their diet.

This content focuses on the the best cancer-fighting foods and also explains the science that supports these claims.

The Foods that contains naturally occurring compounds that have potent anticancer properties include:

1. Apples

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Apples contain anticancer properties that may also help prevent inflammation, cardiovascular disease, and infections.

The phrase “an apple a day keeps the doctor away” actually rings fairly true. Apples contain polyphenols that have promising anticancer properties.

Polyphenols are plant-based compounds that may prevent inflammation, cardiovascular disease, and infections.

Some research suggests that polyphenols possess anticancer and tumor-fighting properties.

For example, the polyphenol phloretin inhibits a protein called glucose transporter 2 (GLUT2) plays a role in advanced-stage cell growth in certain types of cancer.

One study from 2018 in the Journal of Food and Drug Analysis suggests that apple phloretin significantly inhibits the growth of breast cancer cells, while not affecting normal cells.

2. Berries

Berries are rich in vitamins, minerals, and dietary fibers. Scientists have shown a lot of interest in berries due to their antioxidant properties and potential health benefits.

One study shows that anthocyanin, which is a compound in blackberries, lowers biomarkers for colon cancer.

Another study demonstrates that the anti-inflammatory effects of blueberries can prevent the growth of breast cancer tumors in mice.

3. Cruciferous vegetables

Cruciferous vegetables, such as broccoli, cauliflower, and kale, contain beneficial nutrients, including vitamin C, vitamin K, and manganese.

Cruciferous vegetables also contain sulforaphane, a plant compound with anticancer properties.

One study shows that sulforaphane significantly inhibits cancer cell growth and stimulates cell death in colon cancer cells.

Another study shows that sulforaphane in combination with genistein, a compound in soybeans, can significantly inhibit breast cancer tumor development and size. Sulforaphane also inhibits histone deacetylase, an enzyme with links to cancer development.

One review recommends 3 to 5 servings of cruciferous vegetables per week for the best cancer-preventive effects.

4. Carrots

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Carrots contain high amounts of beta-carotene, which may prevent certain types of cancer.

Carrots contain several essential nutrients including vitamin K, vitamin A, and antioxidants.

Carrots also contain high amounts of beta-carotene, which is responsible for the distinct orange color.

Recent studies reveal that beta-carotene plays a vital role in supporting the immune system and may prevent certain types of cancer.

A review of eight studies shows that beta-carotene has links to a reduction in the risk of breast and prostate cancer.

Another analysis shows that higher consumption of carrots results in a 26 percent lower risk of developing stomach cancer.

5. Fatty fish

Fatty fish, including salmon, mackerel, and anchovies, is rich in essential nutrients, such as vitamin B, potassium, and omega-3 fatty acids.

One study found that people whose diets were high in freshwater fish had a 53 percent lower risk for colorectal cancer than those low in freshwater fish.

Another study found that consumption of fish oil later in life has links to significantly lower risk for prostate cancer.

Finally, a study following 68,109 people found that people who consumed fish oil supplements at least four times a week were 63 percent less likely to develop colon cancer than those who did not.

6. Walnuts

According to the American Institute for Cancer Research, all nuts exhibit cancer-preventing properties, but scientists have studied walnuts more than other types of nut.

Walnuts contain a substance called pedunculagin, which the body metabolizes into urolithins. Urolithins are compounds that bind to estrogen receptors and may play a role in preventing breast cancer.

In one animal study, mice receiving whole walnuts and walnut oil had higher levels of tumor-suppressing genes than the mice receiving vegetable oil.

7. Legumes

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Legumes are high in fiber, which may help lower a person’s risk of developing cancer.

Legumes, such as beans, peas, and lentils, are high in fiber, which may help lower a person’s risk of developing cancer.

One meta-analysis of 14 studies shows an association between higher legume consumption and lower risk of colorectal cancer.

Another study examines the relationship between the intake of bean fiber and risk of breast cancer.

The study results indicate that people who ate diets high in bean fiber were 20 percent less likely to develop breast cancer than those who did not meet their daily fiber intake.

Supplements and medications

Although the foods listed above are everyday products and readily available, some people may not want to make significant dietary or lifestyle changes. In this case, there are plenty of supplements and medications available that contain anticancer compounds.

Vitamins A, C, and E are notable for their anticancer properties and are available as supplements in most major grocery stores.

Most of the plant-based compounds listed throughout this article, such as phloretin, anthocyanin, and sulforaphane, come in pill form.

Over-the-counter medications, such as aspirin and ibuprofen, may also lower the risk of cancer in some people.

Always speak to a medical professional before starting a new medication or supplement regimen.

Cancer can affect every aspect of your health, including your appetite and diet. Selvi Rajagopal, M.D., a specialist in internal medicine at Johns Hopkins Medicine, explains why your diet is so important during cancer treatment, and provides tips on foods to add and avoid.

How does cancer treatment affect your diet?

Treatments such as chemotherapy and some forms of radiation therapy can cause a variety of side effects, including:

  • Constipation, which can cause discomfort and further reduce your desire to eat
  • Diarrhea, which can drain your body of nutrients
  • Fatigue, which means you’re less active, so you burn fewer calories and don’t feel as hungry throughout the day
  • Loss of taste, which can make food unappealing
  • Nausea and vomiting, which might reduce your appetite and cause weight loss

“Sometimes it also depends on the specific type of cancer you have,” explains Rajagopal. “Treatment for breast cancer and blood cancers often involve steroids. Steroids can actually increase your appetite and increase your blood sugar levels, which might lead to insulin resistance and weight gain. So instead of losing weight, it’s possible to gain quite a bit of weight from the combination of medications and a more sedentary lifestyle during cancer treatment.”

Some people also have hormone therapy after chemotherapy for breast cancer or endometrial cancer. The drugs suppress production of estrogen, a hormone that plays an important role in metabolism. If your metabolism slows down, you may put on weight.

People with pancreatic cancer often find it difficult to maintain their weight. Since the pancreas isn’t functioning the way it should, they may not be able to digest food normally. This can lead to weight loss or malnourishment.

Why is your diet important during cancer treatment?

Since cancer treatment can lead to fluctuations in appetite and body weight, it’s important to pay close attention to your diet. In addition to helping you maintain a healthy weight, eating a balanced diet during chemotherapy or radiation therapy can:

  • Help manage treatment side effects
  • Increase energy
  • Increase muscle tone
  • Preserve immune function
  • Reduce inflammation

What foods should you add to your diet during cancer treatment?

“Anyone with a chronic illness, even if it’s not cancer, should eat foods high in protein, healthy fats, whole grains, and vitamins and minerals,” Rajagopal emphasizes. “If possible, make these dietary adjustments before cancer treatment begins so you’ll be healthier going into treatment.

Plant-based Proteins

Some of the best foods to eat during chemotherapy or other cancer treatments are plant-based proteins. They offer the highest levels of vitamins and minerals, Rajagopal says. This means eating lots of vegetables as well as beans, legumes, nuts and seeds. If you do eat animal proteins, choose lean options like chicken or fish.

Healthy Fats

Monounsaturated and polyunsaturated fats also have health benefits. Avocados, olive oil, grapeseed oil and walnuts are all high in omega-3 fatty acids, which help combat inflammation and improve cardiovascular health.

Healthy Carbs

When choosing carbohydrates, opt for foods that are minimally processed, like whole wheat, bran and oats. These have soluble fiber, which helps maintain good gut bacteria. Soluble fiber also promotes the production of short-chain fatty acids (SCFAs), which lend a hand to everything from metabolism to cellular repair.

Vitamins and Minerals

“Vitamins and minerals help our bodies’ enzymatic processes, which play a big role in boosting immune function and reducing inflammation,” Rajagopal says. When possible, select foods fortified with vitamin D. These may include milk, orange juice, yogurt and some cereals.

Should you take supplements during cancer treatment?

If you’re not eating as much as usual during treatment, or if you have side effects like vomiting and diarrhea that cause you to lose vitamins and nutrients, you might consider taking a multivitamin.

“Vitamin D tends to be the most common vitamin deficiency,” says Rajagopal. “Vitamin D helps keep your immune system strong, reduces fatigue and supports bone health. Especially if you’re on steroids, you’ll be at risk for bone density loss.”

Talk to a registered dietitian and your oncologist before adding any vitamins or supplements to your diet.

How can your diet help manage cancer treatment side effects?

Some dietary changes can help you manage side effects after your treatment begins. These side effects include:

  • Appetite loss. Eat small meals or nutritious snacks throughout the day, rather than three large meals.
  • Constipation. Drink plenty of water, consider a fiber supplement, and add veggies and beans to your meals.
  • Diarrhea. Choose foods or drinks with sodium (sports drinks or broth) and potassium (bananas and all natural fruit juices).
  • Loss of taste. Knowing what to eat when you can’t taste can be difficult. Consider trying new foods with different spices or marinades. You can also add strong flavors, such as lemon or lime juice.
  • Nausea. Anti-nausea foods include citrus, ginger and peppermint oil. You can suck on a slice of lemon, drink ginger tea or eat ginger chews.

What foods should you avoid during cancer treatment?

Be aware of what’s going into your body during cancer treatment. Read nutrition labels and prepare as much of your own food as you can. It’s best to stay away from highly refined, processed food. You should also avoid fried foods that contain a lot of hydrogenated oils, which can increase inflammation.

Since people with cancer often have compromised immune systems, consider skipping foods that carry the risk of foodborne illnesses, including:

  • Lightly cooked or raw fish, such as sushi
  • Soft-cooked eggs or foods that contain raw eggs, such as homemade mayonnaise
  • Unpasteurized cheeses and dairy products
  • Unwashed fruits or vegetables

Planning your cancer treatment diet

Registered dietitians have specialized training in the nutritional needs of people with specific diseases. Your dietitian can help you plan meals that give you the right number of calories and nutrients.

“It’s also important to build an eating plan that’s practical for you,” says Rajagopal. If you’re busy in the evenings and don’t have the time or energy to cook, try to select healthy takeout options. If you’re on a budget, adding inexpensive, nutritious foods like beans or frozen fruit or vegetables to simple meals can go a long way.

Try to eat a variety of vegetables—dark green, red, and orange, fiber-rich legumes (beans and peas), and others. Include fruits, especially whole fruits with a variety of colors in your diet. Eat plenty of high-fiber foods, like whole-grain breads and cereals.
Citrus fruit, like grapefruits and oranges, may have a role in preventing certain cancers. One large study in Japan found that people who had citrus fruits or juices 3-4 days a week were less likely to get cancer than those who had them 2 or fewer days a week.
Should I eat dairy foods? The current evidence that dairy products can protect against cancer or increase the risk of cancer is not conclusive. Cancer Council supports that the proven health benefits of dairy foods outweigh the unproven harms. Dairy foods should be eaten as part of a varied and nutritious diet.
A starch found in bananas can reduce some cancers by more than half, according to a 20-year trial. The international study, which included researchers from the University of Leeds, has shown a major preventive effect from resistant starch among people with high hereditary risk of cancer.
The American Cancer Society recommends eating at least 2½ cups of vegetables and fruits each day, limiting red and processed meats, and choosing whole-grain instead of refined-grain foods. A healthy breakfast focuses on fruits, vegetables, whole grains, low-fat dairy products, and lean proteins.
You may also want to avoid certain fruits based on your symptoms. For example, citrus fruits may irritate mouth sores and worsen the feeling of dry mouth. Lastly, whole fruits like apples, apricots, and pears are hard for some people with cancer to eat due to mouth sores, difficulty swallowing, dry mouth, or nausea.
Rice components have been reported to inhibit the growth of breast cancer cells without harming normal cells and to increase the treatment effects of the chemotherapy drugs Adriamycin (doxorubicin) and Taxol (paclitaxel).
Broccoli, cabbage, collard greens, kale, cauliflower and Brussels sprouts are all cruciferous vegetables. This vegetable family contains powerful phytochemicals, including carotenoids, indoles and glucosinolates and isothiocyanates, which have been studied and shown to slow the growth of many cancers.
On good days, eat lots of protein and healthy calories. That will keep your body strong and help repair damage from your treatment. High-protein foods include: Lean meat, chicken, and fish.
Looking for a quick, healthy snack to increase your protein and calcium intake during cancer treatment? Greek yogurt could be a great option.
Answer: For most types of cancer, coffee appears either to decrease risk of cancer, or to have no effect on cancer risk at all. Even in countries with very high intake of caffeine from coffee, such as Scandinavian countries, research does not support a link between coffee or caffeine and cancer risk.
Cucumbers are rich in flavonoids that might help to fight cancer. According to a 2012 study published in the Journal of Cancer Research, the dietary flavonoid fisetin found in cucumbers may be able to slow the progression of prostate cancer.
Anthocyanins — a group of antioxidants found in purple sweet potatoes — have been found to slow the growth of certain types of cancer cells in test-tube studies, including those of the bladder, colon, stomach, and breast.
Not only do tomatoes contain lycopene, the antioxidant phytochemical that also helps prevent heart disease, but they’re a good source of vitamins A, C, and E — all enemies of cancer-friendly free radicals.

Takeaway

Research into preventing cancer through diet is still in the early stages and requires further testing. Scientists carried out most of the studies mentioned in cells or mice. However, it is important to remember that eating a balanced diet high in fresh fruits, vegetables, and good fats will benefit overall health.