New research out this week from the American Institute for Cancer Research adds to the growing body of knowledge about actions women can take to lower their breast cancer risk. The new report is an update of previous research, adding results of 81 new studies to the findings of more than 800 that have followed women in the United States and around the world to see who develops breast cancer and who doesn't. The study authors contend that some 70,000 cases of breast cancer—representing 40 percent of new U.S. cases—could be prevented every year if women followed these measures.
I'm always a little hesitant to report about research that lowers your cancer risk. Leading breast surgeon Susan Love, author of Dr. Susan Love's Breast Book, has told me time and time again that the vast majority of breast cancers—the ones not triggered by an inherited gene mutation—have no known cause. And it's tough to tease out particular lifestyle habits that protect us from cancer since women who, say, exercise a lot may be more health conscious in general, eating better and seeing their doctor more often than those who don't. What's more, I think such research inadvertently conveys the message that people are somehow to blame for their cancers. With the exception of smoking and lung cancer, that's simply not the case. (And there are plenty of folks who develop lung cancer and never smoked a day in their life.)
Still, there are some very concrete things we can do to maximize our odds of thwarting breast cancer. "We're not blaming the victim," study leader Susan Higginbotham said on an MSNBC interview posted on the AICR Web site. Rather, she says the study provides good news for women, things they can do to protect themselves. They are the following:
1. Be as lean as possible without being underweight. A healthy body mass index is defined as being above 18.5 but no greater than 25; that's equivalent to a weight range of 105 to 142 pounds for a 5-foot 4-inch woman. Studies have shown, though, that women closer to the lower end of the healthy weight range have the most protection from breast cancer.
2. Exercise for at least 30 minutes a day. Higgenbotham says if you can't do that, do less. Some activity is better than none, but the more, the better.
3. Limit alcohol consumption. If you drink at all, limit your intake to one serving a day—a glass of wine (5 ounces), shot of liquor (1.5 ounces), or bottle of beer (12 ounces).
4. Breast-feed. New mothers should breast-feed exclusively for up to six months since the AICR says "evidence is convincing that mothers who breast-feed reduce their risk for breast cancer." Breast-feeding may also lower the child's risk of obesity later in life.
Many breast cancer patients have low levels of vitamin D, which could lead to weaker bones and increased risk of fractures, say U.S. researchers who recommend high doses of vitamin D for them.
Peppone and colleagues studied 166 women undergoing treatment for breast cancer and found that nearly 70 percent had low levels of vitamin D in their blood. The average level among the women was 27 nanograms of vitamin D per milliliter of blood. Levels of 32 nanograms per milliliter are adequate, according to the U.S. Institute of Medicine.
The lowest levels of vitamin D were in non-whites and those with late-stage breast cancer.
The researchers found that weekly supplementation with high doses of vitamin D (50,000 IU or more) boosted the levels of the vitamin among all the women.
The study was to be presented Oct. 8 at the American Society of Clinical Oncology's breast cancer symposium in San Francisco.
Previous studies have shown that nearly half of all women and men have vitamin D levels below 32 nanograms per milliliter. Along with strengthening bones, vitamin D plays an important role in cell growth and keeping the immune system strong. People obtain Vitamin D through exposure to sunlight and from foods such as milk and fortified cereals.