Young women who suffer from anorexia appear to have a lower risk of breast cancer later in life.
Certainly, no one is promoting the benefit of eating disorders, which can lead to heart disease, osteoporosis and many other problems. But the new findings suggest that calorie restriction may protect against the disease.
Researchers from Brigham and Women's Hospital in Boston and Karolinska Hospital in Stockholm studied 7,303 women, age 40 and younger, who had been hospitalized after drastically limiting their eating. The researchers then cross-referenced those patients with the Swedish Cancer Registry and the Swedish Fertility Registry.
The authors found that the women hospitalized for anorexia had a 53% lower incidence of breast cancer when compared with women from the general population. They also found that being anorexic and having children further lowered the risk.
Anorexic women who had become mothers had a 76% lower incidence, compared with a 23% lower incidence among anorexic women who never had children.
"Our observations indicate that breast cancer may originate during the early phases of a woman's life, from puberty to early adulthood, and that diet during this phase may be important to reduce future risk of breast cancer," lead author Karin B. Michels, an associate professor at Harvard Medical School, said in a statement.
Although the researchers don't know precisely why the breast cancer risk fell for formerly anorexic women, they said that starvation during adolescence and early adulthood -- the period when most anorexia occurs -- could affect breast cell growth and development.
It may lower the rates of cellular proliferation, alter the expression of cancer-causing genes and decrease levels of estrogen, which has been linked to cancer, they said.
Anorexia also may lower levels of a hormone called insulin-like growth factor, which has been used as a marker to predict cancer.
The study was published in the March 10 issue of the Journal of the American Medical Assn.