According to a recent article published in the Journal of the National Cancer Institute, adolescent girls who eat a low-fat diet have lower levels of hormones linked to breast cancer in adulthood.
Breast cancer is the second leading cause of cancer death in women in the United States, with approximately 200,000 cases diagnosed each year. Although several risk factors have been associated with breast cancer, the cause of the majority of cases of breast cancer remains unknown. As researchers continue to explore the causes of this disease, they also uncover factors that may prevent the development of breast cancer. Often, lifestyle changes and choices can help reduce the risk of cancer, including diet.
Between 1988 and 1997, 286 girls participated in the Dietary Intervention Study in Children that measured how diet could affect levels of low-density lipoproteins (LDLs), which are often referred to as “bad” cholesterol. The same participants were also screened as part of this hormone study. The girls, between the ages of 8 and 10, were randomly assigned to one of two groups. In the treatment group, the girls received nutrition counseling individually and as a group on how to follow a low-fat diet (28% of calories from fat, no more than 8% from saturated fat). The other group received written material from the American Heart Association, but did not undergo any counseling. Blood samples were collected at years 1, 3 and 5 and analyzed to determine sex hormone levels.
After five years, the girls who had undergone nutritional counseling had significantly lower levels of hormones that have been linked with breast cancer in adulthood. Estradiol levels were 29.8% lower, estrone levels were 20.7% lower and progesterone levels were around 50% lower in the treatment group than the group that did not receive any nutritional counseling. The counseled girls also reported consuming fewer calories, less fat and saturated fat and more fiber, all factors that may also decrease risk of developing breast cancer.
Researchers concluded that “modest reductions in fat intake during puberty are associated with changes in sex hormone concentrations” that are linked with adult breast cancer. However, the study was not designed to determine whether these lower levels of sex hormones translate into lower rates of breast cancer later in life. Additional research is needed to explore this potential relationship.
Reference: Dorgan JF, Hunsberger SA, McMahon RP, et al. Diet and sex hormones in girls: findings from a randomized controlled clinical trial.
Journal of the National Cancer Institute. 2003;95(2):132-41.