What should I eat to prevent breast cancer?

By Cheryl Reid-Simons

The bad news is there’s still no magic pill to help you prevent breast cancer. But the good news is that you might just have some great tools to fight the disease already in your refrigerator or pantry.

MultiCare oncology dietitian Kelay Trentham, MS, RDN, CSO, says that while most women get the message about mammograms and regular self-exams to detect breast cancer early, too many don’t realize there are simple things everyone can do to help reduce the chances of getting the disease in the first place. And perhaps more important, those same things can help cancer survivors reduce their chances of recurrence.

First, a few things to avoid. Alcohol and processed meats top that list.

“Increasingly we’re seeing evidence that alcohol really puts people at pretty high risk of breast cancer,” Trentham says.

Meat in general should have a minor role in your diet and red meat in particular should be consumed sparingly. Other foods to consume sparingly include sugary beverages and processed foods high in fat, starch and sugar.

Trentham says research is clear that a plant-based diet is the best choice for reducing the chances of developing any kind of cancer.

“That doesn’t mean to never have meats,” she says. “But try to limit animal foods to about 25 percent (and certainly not more than 30 percent) of your total diet.”

For breast cancer in particular, research supports anything from the cabbage family, also known as cruciferous vegetables — broccoli, cauliflower, brussels sprouts and watercress — as helpful. Just about any fruit typically eaten in the American diet will be also full of cancer-fighting chemicals. Think berries, peaches, nectarines, apples, plums and pomegranates.

As a bonus, a diet designed to reduce cancer risk should be extra flavorful and delicious, Trentham says. While you should aim for at least 30 grams of fiber a day, you should also make it a goal to use plenty of herbs and spices.

“Anything in the plant family that has a particularly bright color, strong flavor or strong smell is indicative of high levels of phytochemicals included in those foods,” Trentham says.

Phytochemicals seem to be the key to making those foods cancer fighters.

“The phytochemicals can repair and prevent DNA damage,” she says.

And when phytochemicals encounter cells undergoing cancerous changes, “they may even assist in telling those cells ‘You were supposed to die a few generations ago, it’s time for you to kick it,’” Trentham adds.

But don’t fall prey to supplements that suggest they can give you the phytochemicals in plants while skipping out on your greens. Multiple studies have shown that extracting the chemicals from plants and using them as supplements doesn’t work. In some cases, it even seemed to have negative impacts.

“Nutrition research is tricky,” she admits. “We tend to try to boil things down into individual nutrients and magic bullets, but it just doesn’t work that way.”

More evidence points to the overall diet pattern as being beneficial rather than just individual food items.

Trentham bases much of her recommendations on findings compiled by the American Institute for Cancer Research. The AICR has conducted careful, systematic literature reviews of thousands of studies. The resulting findings give us our best information to date on cancer prevention and survivorship.

The AICR research surprises some people, Trentham says. For example, one of the big myths is that you can’t have any soy if you have breast cancer.

The confusion comes from the fact that soy contains chemicals called phytoestrogens because they are very similar to — but not identical to — estrogen.

“Plants do not make estrogen,” she says. In truth, “a few servings a day of whole soy can actually reduce recurrence of breast cancer.”

That’s based on findings in humans, an important distinction from studies on animals because “our physiology is different from a rat or a mouse,” she adds.

Like soy, dairy sometimes gets a bad rap.

“That data is not very clear,” Trentham says. “There have been some studies suggesting that for breast cancer it may be wise to use low-fat or preferably fat-free dairy.”

But if you’re worried about hormones in dairy, those fears are probably misplaced simply because the amount you ingest is tiny compared to what you naturally have circulating in your body.

The bottom line: Consume a whole foods diet rich in plant foods, herbs and spices, and include some whole soy foods while limiting animal foods, added sugars, processed meats and alcohol.

Kelay Trentham, MS, RDN, CSO, is a board-certified specialist in oncology nutrition at the MultiCare Regional Cancer Center. Learn more about the program and our multidisciplinary cancer care team.