Can certain foods really reduce your cancer risk?

Tomatoes and tomato-based products

Studies have long connected tomatoes to the reduced risk of prostate cancer thanks to their abundant stores of lycopene, a potent antioxidant that gives tomatoes their red colour.

Loading

But lycopene may be just one of many compounds in tomatoes that help defend against prostate cancer, says Nancy Moran, an assistant professor of nutrition at the Baylor College of Medicine in Houston. And limited research has found that lycopene may also possibly protect against other cancers like breast, lung and colorectal.

Processing tomatoes, such as by cutting or cooking them, helps us absorb lycopene more easily than when we eat them raw, Moran says. Consuming tomatoes with fat helps, too. So eating them cooked, such as in a sauce or with a healthy fat like olive oil, can help boost the health benefits you get from them.

Beans and other types of legumes

Common bean varieties like black and kidney beans, and legumes like chickpeas, dry peas and lentils, are not only high in protein. They’re also great sources of fibre, which is crucial for gut and immune health, Brockton says.

Fiber is also linked with colorectal cancer prevention. The bacteria in our gut break fibre down into fuel for the cells lining the colon, which keeps them healthy and less likely to turn into cancer cells, Brockton says.

Henry Thompson, director of the Cancer Prevention Laboratory at Colorado State University, says that in animal and human studies, the consumption of beans (and other pulses such as chickpeas and lentils) has been linked with the prevention of obesity, which is tied to several cancers. One ongoing clinical trial in humans is testing whether eating canned beans reduces cancer risk.

According to Brockton, the protective benefits of fibre kick in after eating around 30 grams – or the amount in about 2 cups of black beans – per day.

Nuts, especially walnuts

Tree nuts are rich in healthy fats, protein and fibre, and studies have found that those who consume them tend to have reduced risks of various types of cancer, especially those of the digestive system.

Walnuts in particular contain exceptionally high levels of plant compounds called ellagitannins, which are converted by our gut bacteria into metabolites that may reduce cancer’s ability to grow and multiply.

Dr John Birk, a gastroenterologist at UConn Health who has performed colonoscopies for people in clinical trials that investigate the colon health benefits of walnuts, says that it was easy to spot a “walnut colon”. The lining of the colon wall “has a healthier appearance, a sort of glistening reflection of the light shining on it from the endoscope,” he says.

Studies suggest that eating about a handful of tree nuts per day is linked with health benefits.

Berries

Loading

Fleshy fruits like strawberries, blueberries, cranberries and pomegranates are packed with antioxidants including vitamin C and flavonoids that help protect cells from stress and DNA damage that can increase cancer risk. Plant compounds called anthocyanins give berries their colourful hues and anti-inflammatory heft, and reducing inflammation is important because it “is a big driver of cancer,” Brockton says.

Dorothy Klimis-Zacas, a professor of clinical nutrition at the University of Maine, says a growing body of evidence suggested that certain compounds in berries may help reduce cancer’s ability to develop, grow and multiply.

For the most anti-inflammatory benefits, aim for about one-half to 1 cup of fresh or frozen (and ideally organic) berries per day, she says.

Garlic

This pungent allium contains high levels of allicin, a sulfur-containing compound that is responsible for garlic’s strong odour and cancer-fighting abilities.

In one long-term study of more than 3000 people who live in a region of China known to have high rates of stomach cancer, researchers found that for every 2.2 pounds of garlic that participants consumed per year, they had a 17 per cent reduced risk of developing the disease. That’s about five cloves of garlic per week, says Wen-Qing Li, a cancer researcher at Peking University Cancer Hospital in Beijing and an author of the study.

Other, mostly nonhuman, studies have suggested possible links between garlic consumption and reduced risks of other types of cancer, especially colorectal cancer.

According to Li, consuming garlic raw – pressed into oil for salad dressing or in guacamole, for example – will help “to keep the flavours and chemicals inside alive.”

The New York Times

Make the most of your health, relationships, fitness and nutrition with our Live Well newsletter. Get it in your inbox every Monday.