How Your Diet May Affect Your Risk of Breast Cancer

smiling woman cuts carrots and broccoli in kitchen

Have you ever said “no thanks” to a tempting dessert or eaten only salad for lunch because you were trying to cut back? If so, you’re among many women who try every day to protect their health by eating right. The American Cancer Society recommends eating mostly vegetables, fruits, and whole grains, and less red meat (beef, pork, and lamb), less processed meat (bacon, sausage, luncheon meats, and hot dogs), and fewer sweets. A healthy diet can help reduce the risk of heart disease, diabetes, stroke, and certain cancer types.

A healthy diet can also help you get to and stay at a healthy weight. Overweight and obesity increase the risk for getting breast cancer. What’s less clear is the link between breast cancer risk and any one food type. Many studies about foods and breast cancer risk have had different results, but no clear-cut answers. Here is what the evidence tells us about fat, vitamin supplements, soy, dairy, and sugar.

Fat

Many studies have found that breast cancer is less common in countries where the typical diet is low in total fat, low in polyunsaturated fat, and low in saturated fat. But most studies that looked at the amount of fat eaten by women in the United States did not find a link to breast cancer risk. This could be because women in countries where breast cancer is less common also have other differences besides the amount of fat they eat. Those differences may include how much physical activity they get, what else they eat, and genetic factors.

Vitamin Supplements

So far, no study has shown that taking vitamins reduces breast cancer risk. Dietary supplements are not regulated like medicines in the United States - they do not have to be proven effective (or even safe) before being sold, althrough there are limits on what they're allowed to claim they can do. Food is the best source of vitamins and minerals. If you take vitamins or are thinking about starting, you should talk to your doctor about it.

Soy

Soy contains compounds called isoflavones. Isoflavones can act like estrogen in the body and may help protect against hormone-dependent cancers. There is growing evidence that eating traditional soy foods such as tofu may lower the risk of cancers of the breast, prostate, or endometrium (lining of the uterus), and there is some evidence it may lower the risk of certain other cancers. This might be because the isoflavones can actually block the more potent natural estrogens in the blood.

Whether this applies to foods that contain soy protein isolates or textured vegetable protein derived from soy is not known.

Dairy

Some early studies raised concerns about whether drinking milk from cows treated with hormones can raise risk of breast cancer or other types of cancer. But later studies failed to find a clear link. At this time, it is not clear that drinking milk produced with or without hormone treatment is of any concern regarding cancer risk or other health effects

Sugar

A myth says: “Sugar feeds cancer.” But the truth is that sugar doesn't make cancer grow faster. All cells, including cancer cells, depend on blood sugar (glucose) for energy. But giving more sugar to cancer cells doesn't make them grow faster and starving them of sugar doesn’t make them grow slower.

However, eating a lot of sugar, including desserts and sugar-sweetened beverages, can lead to weight gain, which may increase the risk of breast cancer.

The American Cancer Society medical and editorial content team
Our team is made up of doctors and master’s-prepared nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.


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