Breast cancer is the second most common cancer in American women. According to the Centers for Disease Control and Prevention, 264,000 women are diagnosed in the United States annually, and approximately 42,000 women die from breast cancer (CDC, 2022).
Research demonstrates that obesity in women increases the risk of developing breast cancer, especially in postmenopausal women. In addition, obesity also worsens the disease outcome for women of any age. For postmenopausal but not premenopausal women, a recent paper reports that obesity is associated with estrogen-positive breast cancers. Fortunately, the same paper reports that weight loss in adulthood lowers the risk of breast cancer. Obesity increases circulating estrogens and inflammatory compounds that fuel breast cancer.
The Women's Health Initiative Dietary Modification clinical trial is one of the most extended studies evaluating breast cancer mortality and dietary intervention. In this trial 48, 835 postmenopausal women without a history of breast cancer were randomly assigned to the dietary modification (DM) or usual diet groups. The women ages 50-79 years had a dietary intake ≥ 32% of total energy intake as assessed by food frequency questionnaire. The low-fat DM protocol included reducing fat intake to 20% of calories and increasing vegetables and fruits to 5 servings daily and grains to 6 servings daily. Women were monitored with mammograms and given nutritional and behavioral sessions. Overall, the women following the DM had modest weight loss and significantly reduced risk of death from breast cancer. Moreover, there was a substantial decrease in the incidence of estrogen-positive breast cancers, which is very common in women with breast cancer. The authors also noted that anti-estrogen drugs have not been shown to reduce deaths from breast cancer, but this dietary protocol had a mild death reduction benefit. In my opinion, it would be helpful for researchers to be more specific about differentiating between healthy fat intake (omega 3 and 9) instead of total fat intake.
Dr. Mark Stengler NMD, MS, is a bestselling author in private practice in Encinitas, California, at the Stengler Center for Integrative Medicine. His newsletter, Dr. Stengler’s Health Breakthroughs, is available at www.markstengler.com and his product line at www.drstengler.com
Centers for Disease Control and Prevention. (2022, September 26). Basic information about breast cancer. Basic Information About Breast Cancer. https://www.cdc.gov/cancer/breast/basic_info/index.htm#:~:text=Each%20year%20in%20the%20United,What%20Is%20Breast%20Cancer%3F
Chlebowski, R. T., Aragaki, A. K., Anderson, G. L., Pan, K., Neuhouser, M. L., Manson, J. E., Thomson, C. A., Mossavar-Rahmani, Y., Lane, D. S., Johnson, K. C., Wactawski-Wende, J., Snetselaar, L., Rohan, T. E., Luo, J., Barac, A., Prentice, R. L., & Women’s Health Initiative (2020). Dietary Modification and Breast Cancer Mortality: Long-Term Follow-Up of the Women's Health Initiative Randomized Trial. Journal of clinical oncology: official journal of the American Society of Clinical Oncology, 38(13), 1419–1428.:https://doi.org/10.1200/JCO.19.00435.
Picon-Ruiz, M., Morata-Tarifa, C., Valle-Goffin, J. J., Friedman, E. R., & Slingerland, J. M. (2017). Obesity and adverse breast cancer risk and outcome: Mechanistic insights and strategies for intervention. CA: a cancer journal for clinicians, 67(5), 378–397. https://doi.org/10.3322/caac.21405.
