Feb. 21, 2003 -- Teenaged girls who want to reduce their chances of developing breast cancer later in life may be wise to forgo that morning bagel in favor of an omelet cooked in olive oil. And don't forget the whole-wheat toast.
Preliminary research suggests that eating eggs, vegetable oils, and dietary fiber during adolescence just might be protective against the most common cancer among women. The survey of more than 121,000 women also found that eating butter slightly increased breast cancer risk, but other animal fats appeared to have no impact on risk. The study is reported in the March issue of the journal Breast Cancer Research.
Diet during childhood and adolescence has long been suspected of playing a role in future risk of breast cancer. Breast cancer incidence is low among first-generation Asian immigrants to the U.S., but rises to the U.S. average within two or three generations, suggesting that exposures early in life are important. In an effort to identify foods that either protect against breast cancer or increase risk, researcher Graham A. Colditz, MD, and colleagues surveyed women taking part in Harvard Medical School's Nurses' Health Study about their dietary habits between the ages of 12 and 18.
After controlling for known breast cancer risks, such as family history of disease or use of hormone replacement therapy, the researchers found that eating about three eggs a week during adolescence decreased the risk of breast cancer by 18%. Diets rich in vegetable oils and dietary fiber had similar effects. But eating roughly one pat of butter a day increased risk by 6%.
Colditz tells WebMD that eggs may be protective because they are high in essential amino acids, vitamins, and minerals. And studies suggest that fiber-rich foods reduce estrogen levels. Estrogen is critical for the growth of the breast but has also been linked to breast cancer.
An epidemiologist with the Harvard School of Public Health, Colditz warns that the findings are very preliminary and have more relevance to researchers than the general public.
"It is certainly premature to say that these are the foods that adolescent girls should be eating to reduce their risk," he says. "What this does is give us an idea which foods we should look at further. This is really a first attempt to see if we could find components of diet that may influence the risk of breast cancer."
Dietitian Melanie Polk, MMSC, calls the research intriguing but says she is skeptical about the accuracy of a survey that asked respondents to remember what they ate three and four decades ago -- a concern also expressed by the researchers. Polk is director of nutrition education for the American Institute for Cancer Research.
"If someone were to ask me what I ate when I was a teenager, I'm not sure I could tell them," she tells WebMD. "But this study does raise some interesting questions. While we wouldn't give out dietary recommendations on the basis of one study, this research will help direct us in terms of future research."