By Joseph E. Scherger, MD, MPH
Vice President, Primary Care, Eisenhower Medical Center; Clinical Professor, Keck School of Medicine, University of Southern California, Los Angeles
Dr. Scherger reports no financial relationships relevant to this field of study.
SYNOPSIS: An improvement in diet over 12 years in middle-aged nurses and other health professionals resulted in a decreased risk of death.
SOURCE: Sotos-Prieto M, Bhupathiraju SN, Mattei J, et al. Association of changes in diet quality with total and cause-specific mortality. N Engl J Med 2017;377:143-153.
A team of investigators at the Harvard T.H. Chan School of Public Health and other institutions studied data of 47,994 women in the Nurses’ Health Study and 25,745 men in the Health Professionals Follow-up Study collected between 1998 and 2010. Participants’ self-reported diets from the previous 12 years (1986-1998) were analyzed using three diet-quality scores: the Alternate Healthy Eating Index, the Alternate Mediterranean Diet, and the DASH diet. Those who improved their diets were compared with those who did not. A 20% increase in diet scores was associated significantly with a reduction in total mortality of 8-17%, depending on the score used. There was a 7-15% reduction in the risk of death from cardiovascular disease. The most common diet changes indicating improvement were increased consumption of vegetables, whole grains, and omega-3 fatty acids, and decreased sodium intake.
Large population nutrition studies are difficult, given the variable nature of most people’s diets and the inaccuracies of self-reporting. This study was powered adequately enough to suggest a real effect of diet on mortality. The results are not surprising. The authors cited 10 other studies that support an association between healthy dietary patterns and a decreased risk of death. Lifestyle is the dominant contributor to chronic disease and premature death. Nutrition plays the greatest role in a healthy lifestyle, followed by physical activity. We know what foods contribute to poor health, obesity, type 2 diabetes, cardiovascular disease, and premature death: excess sugar, refined carbohydrates, inflammatory proteins, and unhealthy fats. As Michael Pollan wrote so clearly, clinicians should recommend patients eat real food and not “food-like substances.”1 Admonitions by a physician are powerful to patients, so clinicians should recommend healthy nutrition to every patient. This may be the most common way clinicians can save lives.
- Pollan M. In Defense of Food: An Eater’s Manifesto. New York: Penguin Books; 2008.