Calorie Restriction Lowers Breast Cancer Risk
Study Offers Clues About the Role of Early Diet in Disease
Study Findings continued...
Researchers identified more than 7,300 women in Sweden who had
been hospitalized for anorexia prior to age 40 over a three-decade period. A
comprehensive national cancer registry was used to compare breast cancer
frequency among the former anorexia patients to that of the population at
Women with a history of the eating disorder were 53% less
likely to get breast cancer than the general female population.
This jumped to a 76% reduction in breast cancer risk in those
women who had also given birth. Pregnancy has long been linked to reduced
breast cancer risk.
Possible reasons for the observed reduction in breast cancer
risk include decreased levels of estrogen and other growth hormones among women
on extremely low calorie diets and the restrictive impact that such diets have
on cell division.
"Very low calorie intake and low body weight are associated
with low estrogen levels, and low estrogen levels have been linked to a lower
risk of breast cancer," says Brigham and Women's Hospital chief of
obstetrics and gynecology Robert Barbieri, MD.
Another possible reason for the association, Barbieri says, is
that people on very low calorie diets have lower levels of human growth
hormones such as insulin-like growth factor type 1 (IGF-1). Animal studies show
that IGF-1 can promote tumor growth. Barbieri was not involved in the
"In worms, growth hormones have been directly linked to
life expectancy, and people are wondering if this might be another way in which
calorie intake could regulate cancer risk," he tells WebMD.