Study: Metabolic Changes due to Aerobic Exercise May Decrease Breast Cancer Risk

By Vera Viner

The medical industry and health advocates have been pushing the importance of exercise for decades and breast cancer experts have known the link between physical activity and prevention of this disease. However, the actual mechanisms behind this finding have not been clear. New research has shed new light onto this area.

Dr. Mindy Kurzer, professor in the Department of Food Science and Nutrition at the University of Minnesota, and her colleagues published a new study in the latest edition of the journal Cancer Epidemiology, Biomarkers & Prevention that examines the possibility of changes in estrogen breakdown or metabolism due to aerobic exercise lowering the risk of breast cancer.

The Science Daily reported that the researchers followed 391 young, healthy, premenopausal women for 16 weeks and split them into two groups: one control group based on a sedentary lifestyle and a second intervention group that underwent 30 minutes of moderate-to-vigorous aerobic exercise five times per week.

“Observational studies suggest physical activity lowers breast cancer risk, but there are no clinical studies that explain the mechanism behind this,” Dr. Kurzer told the Science Daily. “Ours is the first study to show that aerobic exercise influences the way our bodies break down estrogens to produce more of the ‘good’ metabolites that lower breast cancer risk.”

In this study, aerobic exercise included using the treadmill, stairmaster, or elliptical machine with a maximal heart rate for each participant. Body fluid samples were collected three days prior to the study and three days after the study concluded.

Liquid chromatography or tandem mass spectroscopy was used to measure the amount of three types of estrogen products and nine metabolites. There is one particular type of estrogen metabolism that has been linked with a reduction in breast cancer risk. Kurzer and her colleagues found that aerobic exercise led to an increase of one type of metabolite and a decrease in a different one.

“Exercise, known to favor fitness and improve heart health, is also likely to help prevent breast cancer by altering estrogen metabolism,” said Kurzer. “It is very important, however, to decipher the biological mechanisms behind this phenomenon.”