Results also suggested that substituting red meat with healthier alternatives, such as fish, whole grains, or vegetables, may lower the risk for death.
“This long-term study provides further evidence that reducing red meat intake while eating other protein foods or more whole grains and vegetables may reduce risk of premature death. To improve both human health and environmental sustainability, it is important to adopt a Mediterranean-style or other diet that emphasizes healthy plant foods,” senior author Frank Hu, MD, PhD, said in a press release. Hu is the Fredrick J. Stare Professor of Nutrition and Epidemiology and chair of the Department of Nutrition at the Harvard T.H. Chan School of Public Health.
Red meat, especially processed meat, contains saturated fat, high levels of sodium, preservatives, and potential carcinogens that can contribute to health problems. Eating red meat has been tied to increased risk for chronic diseases, such as cardiovascular disease, type 2 diabetes, and cancer. Processed red meat, like hot dogs and bacon, has been linked to an even larger number of health problems, as well as increased risk for death
Therefore, Yan Zheng, PhD, from the Department of Cardiology, State Key Laboratory of Genetic Engineering, School of Life Sciences, and Zhongshan Hospital, Fudan University, Shanghai, China, and colleagues analyzed data from two prospective US cohort studies: the Nurses’ Health Study (53,553 women) and the Health Professionals Follow-up Study (27,916 men). Included participants were free from cardiovascular disease or cancer at baseline.
The researchers analyzed data collected between 1986 and 2010. Using validated food frequency questionnaires at baseline and every 4 years, participants self-reported how often over the past year they ate a standard portion of each food. Researchers categorized participants into five categories based on changes in red meat consumption (increased, decreased, or relatively neutral).
Results showed that increased total red meat consumption over the course of 8 years was tied to significantly higher mortality in the following 8 years for both women and men compared with no change in red meat consumption (P for trend < .05).
After adjusting for age, race, smoking, alcohol consumption, and several other factors, including baseline red meat consumption, the researchers found that increasing total red meat consumption by up to 3.5 servings per week over 8 years was linked to 10% higher risk for death compared with no change in red meat consumption (hazard ratio [HR], 1.10; 95% confidence interval [CI], 1.04 – 1.17).
When they distinguished between processed and unprocessed red meat, they found a similar trend, with the risk associated with processed meat higher than that for unprocessed meat. Specifically, increased consumption of processed red meat by up to 3.5 servings per week was tied to 13% increased risk for death (HR, 1.13; 95% CI, 1.04 – 1.23), whereas the same increase in unprocessed red meat consumption was tied to 9% increased risk for death (HR, 1.09; 95% CI, 1.02 – 1.17).
Decreasing total red meat consumption by one to 3.5 servings per week was not linked to risk for death. However, risk for death was substantially lower when red meat consumption decreased in favor of healthier options.
For example, risk for death decreased by 17% when one serving per day of red meat was replaced with one serving per day of fish (HR, 0.83; 95% CI, 0.76 – 0.91). Other healthy alternatives for which risk for death decreased included nuts (HR, 0.81; 95% CI, 0.79 – 0.84), whole grains (HR, 0.88; 95% CI, 0.83 – 0.94), poultry without skin (HR, 0.90; 95% CI, 0.86 – 0.95), vegetables without legumes (HR, 0.90; 95% CI, 0.87 – 0.93), dairy (HR, 0.92; 95% CI, 0.86 – 0.99), eggs (HR, 0.92; 95% CI, 0.89 – 0.96), and legumes (HR, 0.94; 95% CI, 0.90 – 0.99).
The authors note several limitations. The study has an observational design and cannot prove that consumption of red meat causes increased risk for death, only that the two are associated. Most participants were white health professionals with relatively high socioeconomic status; therefore, the results may not generalize to more diverse groups.
The study was funded by grants from the National Institutes of Health, the National Heart, Lung, and Blood Institute, the National Institute of Diabetes and Digestive and Kidney Diseases, and the Boston Nutrition Obesity Research Center.
One or more authors reports support and/or honorariums from one or more of the following: the Boston Nutrition Obesity Research, the California Walnut Commission, Metagenics, Standard Process, Diet Quality Photo Navigation, Shanghai Institutions of Higher Learning, and/or the American Diabetes Association.
BMJ. Published online June 12, 2019. Full text