It's never too late to lower your risk of ovarian cancer, according to a new study published in the Journal of the National Cancer Institute. The results of the Women's Health Initiative Dietary Modification study show convincing evidence that switching to a low-fat diet may lower the risk of developing ovarian cancer by as much as 40 percent. The surprising benefit only appears after eight years on a low-fat diet, so women must stay on the diet for that long. However, the risk of ovarian cancer was significantly reduced, no matter how old the women were when they began the new diet.
The Women's Health Initiative is one of the largest studies to evaluate the effect of dietary patterns and cancer incidence. In this latest randomized trial, more than 48,000 postmenopausal women, ages 50-79, were followed for eight years. The women were divided into two groups: those who followed their usual diet, and a group who followed a low-fat diet. The women in the low-fat diet group reduced their total fat intake to 20 percent of their calories—compared to an average of 35 percent—and ate more vegetables, fruits, and grains. In the first four years, there was no difference in ovarian cancer incidence between the two groups. But after eight years the difference became apparent. Only those who had adhered to a low-fat diet for eight years cut their risk by 40 percent, according to researchers.
How does a low-fat diet prevent ovarian cancer? One of the theories of this dietary advantage is that fat intake increases the amount of estrogen in the body. Estrogen stimulates the ovaries, thus leading to ovarian cancer. In fact, blood tests taken on the women in the low-fat diet group during the study confirmed a 15 percent reduction in estrogen, while the non-diet participants experienced no change in their levels of estrogen.
The eight-year study is arguably one of the most promising and exciting findings of the Women's Health Initiative. For the first time, there is researched-backed data that women who undertake a low-fat diet and stick to it, will likely reduce their risk of ovarian cancer. The benefit may extend to preventing other cancers as well. Admittedly, adhering to a low-fat diet is difficult, so perhaps this study will make it easier by motivating people to start—and continue—on a low-fat diet. Many women feel it's too late to start a cancer prevention diet, but the results of the Women's Health Initiative study suggest staying on a low-fat diet may make a real difference in preventing ovarian cancer. Thanks to this landmark study, we now have one more very important and encouraging reason to adhere to a healthy diet.
The Women's Health Initiative Dietary Modification trial was published in the October 17, 2007 issue of the Journal of the National Cancer Institute.
Rachel S. Beller, MS, RD
Beller Nutritional Institute, LLC
