6 foods that can reduce your cancer risk

1. Broccoli and other cruciferous vegetables

According to Johanna Lampe, a cancer prevention researcher at the Fred Hutchinson Cancer Center, cruciferous vegetables like broccoli, brussels sprouts, and cauliflower are full of isothiocyanates. These plant compounds help cells clear out toxins and repair themselves and are important for cancer prevention.

For example, broccoli has been shown to boost the body's natural lines of defense against damage to cells, Lampe said. And research suggests that having more than four to five servings of cruciferous vegetables per week is associated with a reduced risk of cancer and other chronic conditions.

2. Tomatoes and other tomato-based products

Research has found that tomatoes can reduce your risk of prostate cancer thanks to their abundance of lycopene, an antioxidant that gives tomatoes their red color, Campo reports.

But according to Nancy Moran, an assistant professor of nutrition at the Baylor College of Medicine, lycopene is just one of many compounds within tomatoes that can help protect against prostate cancer. Other research has found that lycopene could also protect against breast, lung, and colorectal cancers.

Processing tomatoes, by cutting or cooking them, can help us absorb lycopene more easily than when eating them raw, Moran said. And consuming tomatoes alongside fat helps as well, so eating tomatoes cooked in a sauce with a healthy fat like olive oil could increase the health benefits you get from lycopene.

3. Beans and other legumes

Bean varieties as well as legumes like chickpeas, dry peas, and lentils are great sources of fiber, which is important for gut and immune health, according to Nigel Brockton, VP of research at the American Institute for Cancer Research.

Fiber has also been linked to colorectal cancer prevention. According to Brockton, our gut bacteria breaks fiber down into fuel for the cells that line the colon, which can keep them healthy and less likely to turn into cancer cells.

Henry Thompson, director of the Cancer Prevention Laboratory at Colorado State University, said animal and human studies have found that consuming beans and other legumes has been linked to preventing obesity, which is itself linked to several cancers.

The protective benefits of beans and other legumes start after eating around 30 grams, or two cups of black beans each day, Brockton said.

4. Nuts

Tree nuts are full of healthy fats, protein, and fiber, and research has found people who eat them typically have lower risks of various types of cancer, especially cancers of the digestive system, Campo reports.

Walnuts are especially full of plant compounds called ellagitannins, which gut bacteria converts into metabolites that can reduce cancer's ability to grow and multiply.

John Birk, a gastroenterologist at UConn Health, has performed colonoscopies in clinical trials to investigate the colon health benefits of walnuts and said it's easy to spot a "walnut colon," as the lining of the colon wall "has a healthier appearance, a sort of glistening reflection of the light shining on it from the endoscope."

5. Berries

Fleshy fruits, including strawberries, blueberries, cranberries, pomegranates, and black raspberries, are full of antioxidants like vitamin C and flavonoids that can help protect cells from stress and DNA damage that can increase cancer risk, Campo reports.

Other plant compounds called anthocyanins can help reduce inflammation, which "is a big driver of cancer," Brockton said.

Dorothy Klimis-Zacas, a professor of clinical nutrition at the University of Maine, said there is a growing body of research suggesting some compounds in berries can help reduce cancer's ability to develop, grow, and multiply.

According to Klimis-Zacas, you should aim for around one-half to one cup of fresh or frozen berries each day to get the most anti-inflammatory benefits.

6. Garlic

Garlic contains high levels of allicin, a sulfur-containing compound that causes garlic's strong scent and can help fight cancer, Campo reports.

In one study of more than 3,000 people in a region of China with high rates of stomach cancer, researchers found that for every 2.2 pounds of garlic participants consumed each year, their risk of developing stomach cancer dropped by 17%.

According to Wen-Qing Li, a cancer epidemiologist at Peking University Cancer Hospital and an author on the study, that's around five cloves of garlic per week.

Other studies, most of which have not been conducted on humans, have found potential links between eating garlic and reduced risks of other cancers, including colorectal cancer.

According to Li, eating garlic raw — such as pressed into oil for salad dressing or in guacamole — can help "to keep the flavors and chemicals inside alive." (Campo, "Well," New York Times, 11/29)

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