Can Eating Strawberries Prevent Cancer?

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When it comes to preventing cancer, can what you eat make a difference?

Certain foods are high in antioxidants, which mop up the free radicals that contribute to cancer. But in studies it’s been a challenge to tease apart the effects of diet alone on cancer risk, since people who eat foods rich in antioxidants also tend to exercise more and avoid smoking, other factors that are known to lower the chances of developing cancer.

Now, in a small study presented at the American Association for Cancer Research, researchers uncovered more intriguing evidence that diet may influence the cancer process, even before it begins. Among three dozen participants at high risk of developing esophageal cancer in China, it turned out that eating strawberries helped prevent early lesions from developing into tumors. That’s right — strawberries.

Tong Chen, a cancer researcher at Ohio State Comprehensive Cancer Center, decided to look at strawberries as a cancer-preventer in humans after animal studies showed that the fruit had anti-cancer effects. With plenty of dried fruit supplied by the California Strawberry Commission, which also funded the study, she focused her trial on 36 participants from three provinces in central China that have among the world’s highest rates of esophageal cancer. She gave the volunteers freeze-dried strawberry powder, which was mixed with water into a drink. The freeze-dried form tends to concentrate whatever beneficial properties the fruit might have. (In her animal work, Chen had tested black raspberries as well, but because that fruit isn’t as common in China, the current trial included only strawberries.)

In many cases, esophageal cancer progresses from pre-cancerous growths that are graded as mild, moderate and severe for their likelihood of advancing into malignancy. Among the participants in the new study, 29 saw their lesions revert to a less dangerous state — from mild to ungraded, or from moderate to mild — after six months of consuming the equivalent of two ounces of strawberries a day.

“We are very excited about this result,” Chen says. “I think this study is very important because we found that strawberries may decrease the histological grade of precancerous lesions and also may reduce some cancer-related events including cell proliferation, inflammation and gene [activity].”

She’s quick to point out, however, that gulping down pints of strawberries isn’t the answer to fighting cancer. A larger, more rigorous trial that includes both people at risk of esophageal cancer and healthy, low-risk controls, who are randomly assigned to dosing with strawberries or a placebo, needs to be conducted.

But in the case of a cancer in which half of those with moderate pre-cancerous lesions go on to develop malignant tumors, and 25% of those with mild lesions do, finding ways to halt their march can have a major impact on the incidence of the disease, especially in areas like central China where rates are high. “This shows us that strawberries may be an alternative or work together with other chemopreventive drugs in the prevention of esophageal cancer,” says Chen. And preventing cancer is always preferable to treating it.