Low Caloric Intake Associated With Reduced Breast Cancer Incidence

Breast cancer is the most common form of cancer in women and second leading cause of cancer death among women in the United States, with one in eight women faced with the risk of developing breast cancer in her lifetime. The number of new cases of breast cancer has increased by one percent per year in the United States since the 1940s.

According to lead author Karin B. Michels, ScD, MSc, MPH of BWH and associate professor at Harvard Medical School (HMS), “These scientific findings are encouraging as they will help researchers better understand the underlying physiology responsible for breast cancer development. 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.”

Prior to beginning this study, Michels and her colleague Anders Ekbom, MD, PhD, professor at Karolinska Hospital, Sweden, hypothesized that reduced caloric intake during adolescence or early adulthood would provide breast health benefits. Their assumption was based on findings made repeatedly in rodents: restricting caloric intake is one of the most effective ways to reduce cancer incidence and extend lifespan in the animal model. Since such experimental conditions cannot be applied to humans, a model had to be found to mimic caloric restriction in humans. Hence, this epidemiologic study targeted a population of 7,303 women from the Swedish Inpatient Registry who severely reduced caloric intake while suffering from severe anorexia nervosa prior to age 40, between the years 1965 and 1998. Information on these women was cross-referenced with the Swedish Fertility Registry that has information on every birth in Sweden since 1924 and the Swedish Cancer Registry, which registers all new cancer cases in Sweden.