Some people refer to berries, fatty fish, walnuts, and other foods as cancer-fighting foods. No single food protects people against cancer, but some foods contain nutrients that may help reduce the risk as part of a balanced diet.

Consuming a varied diet that includes the items mentioned below may help keep a person healthy and reduce their risk of cancer.

It is worth noting that polyphenols, resveratrol, vitamin C, and other nutrients are present in many plant-based foods, so this list is not exclusive.

This article looks at some foods that may lower the risk of cancer. It also explains the science that supports these claims.

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There may be some truth to the saying, “an apple a day keeps the doctor away.” Apples contain polyphenols that have promising anticancer properties.

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

Some research suggests that polyphenols may modulate certain processes that can lead to cancer development.

One 2018 study suggests that apple phloretin significantly inhibits the growth of breast cancer cells without affecting healthy cells.

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

Berries are rich in vitamins, minerals, and dietary fiber. Their antioxidant content may mean they have health benefits.

A 2021 review highlights research that suggests bilberries and lingonberries may inhibit tumor formation and cancer growth in digestive tract cancers.

According to a 2018 review, berries may modify the immune system to help delay cancer development. They may also aid cancer immune therapies, although more research is necessary to understand this potential.

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 potential anticancer properties.

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

Other research 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 suggests 3–5 servings of cruciferous vegetables per week may have cancer-preventive effects.

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.

Research from a Danish cohort study examined the intake of carrots on certain cancer development in 55,756 participants.

The results suggested that raw carrot consumption may reduce the risk of colorectal cancer by 17%. They also suggested raw carrots may protect against:

A 2022 screening trial also associated moderate carrot consumption with a lower risk of colorectal cancer.

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

A 2019 meta-analysis suggested that omega-3 fatty acids from fish had a protective effect against breast cancer in Asian patients.

A 2022 meta-analysis also associates fish consumption with a lower risk of developing colorectal cancer.

However, a 2020 review and meta-analysis states that some studies into cancer risk and fish oil supplementation provide weak associations, suggesting further research may be necessary.

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

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 a 2019 trial, females with breast cancer ate walnuts for 2 weeks between the date of their biopsy and the day of surgery.

Researchers tested tumor tissue samples removed during surgery and compared them with the original biopsy results. They found signs that genetic changes had taken place, which could suggest the suppression of cancerous cell growth.

Legumes, such as beans, peas, and lentils, are high in fiber, which may help lower the risk of some types of cancer.

For example, one study examined the relationship between the intake of bean fiber and the risk of breast cancer.

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

Resveratrol, an antioxidant in red grape skins, has shown promise as a tool for fighting cancer. Some scientists believe that, with further research, it could become part of cancer therapy.

As well as resveratrol, grapes and grape seeds also contain the following nutrients, which have antioxidant and potentially cancer-fighting properties:

  • flavonols
  • phenolic acids
  • anthocyanins, in red and purple grapes
  • proanthocyanidins and other tannins
  • catechins

Research in a 2020 review associates the consumption of whole grains with a 6–12% lower risk of cancer. Some site-specific cancers that whole grains may reduce the risk of include:

In contrast to whole grains, research associated high consumption of refined grains with a higher risk of gastric and colon cancer.

Dark chocolate contains polyphenols, flavonoids, and antioxidants, which, according to a 2022 review, may have a preventive effect against cancer.

Research in another 2022 review and meta-analysis found that people who ate more chocolate had a 12% lower risk of death from cancer.

Olive oil consumption may lower someone’s risk of developing any cancer. Specific types of cancer it may help to prevent include the following:

  • gastrointestinal
  • breast
  • urinary tract
  • upper aerodigestive

A 2022 study on olive oil consumption among 1,567 adults in Spain suggests that two or more tablespoons of olive oil per day offers the maximum benefits, lowering the risk of cardiovascular, all-cause, and cancer mortality.

Supplements can also provide nutrients and antioxidants that may help prevent cancer by reducing oxidative stress, such as vitamin C, vitamin D, and vitamin E.

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

Always speak with a healthcare professional before starting a new medication or supplement regimen.

Here are some frequently asked questions about cancer-fighting foods.

What is the number one cancer-fighting food?

There is no single food that can fight cancer. However, consuming certain foods can provide the body with the nutrients it needs to help reduce the risk of cancer. These include apples, berries, cruciferous vegetables, carrots, fatty fish, and more.

How do you starve cancer cells naturally?

According to Cancer Research UK, some early studies, mostly in animals, have suggested that some cancer cells do not use ketones for energy. This would mean that consuming a diet that is low in carbohydrates and high in fat can help to starve cancer cells by lowering glucose levels.

However, more research into this is necessary. It is best to contact a doctor for advice before making any significant dietary changes.

What is the best mushroom to fight cancer?

In Japan and China, medicinal mushrooms have been approved for the treatment of cancer alongside standard therapies. There are more than 100 types of mushrooms for the treatment of cancer in Asia. Examples include reishi, turkey tail, shiitake, and maitake mushrooms. However, more research is necessary, and the Food and Drug Administration (FDA) has not yet approved any medicinal mushrooms for the treatment of cancer in the United States.

Research into preventing cancer through diet is still in the early stages and requires further testing.

However, it is important to remember that eating a balanced diet containing fresh fruits, vegetables, and good fats will benefit overall health.

People can speak with a healthcare professional if they are concerned about their cancer risk.