The most promising way to prevent breast cancer may lie in your diet: fiber may help reduce your risk of the deadly disease, says a new study published in Pediatrics.
Using data from a long-term study of 44,000 women, researchers from Harvard University found that women who ate about 28 grams of fiber per day, particularly in their teen and young adult years, had a 12 to 16 percent lower risk of getting breast cancer over the course of their lifetimes. Each additional 10 grams of fiber eaten daily—especially fiber from fruits, vegetables, and legumes—seemed to reduce their risk by another 13 percent.
This link is important, as Maryam Farvid, Ph.D., a visiting scientist at Harvard University and lead author notes in the study. When it comes to breast cancer prevention and risk, what you eat is one of the few variables that you have direct control over. (We have some more ways to lower your breast cancer risk.)
But don't despair if you no longer fall into the teen or young adult category. A World Cancer Research Fund study of nearly one million adult women found a five percent decrease in breast cancer for every 10 grams of fiber eaten daily.
"Our analysis suggests that increasing dietary fiber intake may be a promising approach to reduce breast cancer risk," says Dagfinn Aune, a nutritional epidemiologist at Imperial College London and the lead researcher of the WCRF study. "Breast cancer is such a common cancer, and everybody eats, so increasing fiber intake could prevent many cases."
The authors of the Pediatrics paper think fiber may help to reduce high estrogen levels in the blood, which are strongly linked with breast cancer development. "Fiber may increase the excretion of estrogens," adds Aune. A second theory is that fiber reduces blood sugar levels and high blood sugar levels are linked with an increased risk of breast cancer. (Although Aune's research found no correlation with body fat so that explanation seems less likely.)
Regardless of why it works, fiber from whole-food plants definitely seems to help prevent against more than just breast cancer. Other studies have found that fiber may reduce your risk of lung cancer, colon cancer, and mouth and throat cancers. Plus, fiber can help you sleep better, avoid constipation, and lose weight.
The optimal intake for cancer prevention is at least 30 to 35 grams per day, according to the researchers. That's a totally doable amount when you include tasty high-fiber foods like air-popped popcorn, lentils, cauliflower, apples, beans, oatmeal, broccoli, and berries. Try these healthy recipes featuring high-fiber foods.