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People who increased their red meat intake over 8 years had a higher death risk in the following 8 years than people whose meat intake stayed the same. Conversely, decreasing meat intake and replacing it with more healthful alternatives reduced death risk.
These are the main takeaways of new research that investigators have just published in the journal The BMJ. Yan Zheng, a professor at Fudan University in Shanghai, China, is the first author of the paper. Frank Hu, Fredrick J. Stare Professor of Nutrition and Epidemiology and chair of the Department of Nutrition at Harvard T.H. Chan School of Public Health in Boston, MA, is the senior author of the study.
Prof. Zheng and colleagues used data that was available from the Nurses’ Health Study and the Health Professionals Follow-up Study. In total, the researchers examined 53,553 women and 27,916 men who had no cardiovascular disease or cancer at the start of the study.
The team examined whether changes in red meat intake in 1986–1994 correlated with mortality risk in the subsequent 8 years, covering 1994–2002. They also looked at whether changes in red meat intake between 1994–2002 predicted mortality risk between 2002–2010.
Adopting a Mediterranean diet
Prof. Zheng and team found that people who increased their total amount of daily processed meat intake by half a serving or more were 13% more likely to die from any cause.
Increasing unprocessed meat by the same amount daily led to a 9% rise in all-cause mortality risk. Conversely, lowering red meat intake while eating more nuts, fish, skinless poultry, dairy, eggs, whole grains, or vegetables over the same 8-year periods lowered death risk in the next 8 years.
People who increased their red meat intake over 8 years had a higher death risk in the following 8 years than people whose meat intake stayed the same.
The researchers say that these correlations continued to be statistically significant after adjusting for age, physical activity, smoking behavior, dietary patterns, or alcohol intake.
“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,” says Prof. Hu. “To improve both human health and environmental sustainability, it is important to adopt a Mediterranean-style or [an]other diet that emphasizes health[ful] plant foods.”
What may explain the heightened death risk
Although the study was observational and cannot address causality, the researchers venture some possible explanations for the associations that they found. Saturated fats, cholesterol, heme iron, and preservatives are only some of the substances in red meat that negatively impact cardiometabolic health, the scientists say.
Cooking at high temperatures also triggers the production of carcinogenic substances. The metabolite trimethylamine N-oxide, which researchers believe can cause atherosclerosis, is also a product of our gut bacteria responding to red meat intake.
A couple of recent studies, for example, have suggested that even a small intake of red meat increases the risk of premature death, and that red meat consumption may raise the risk of kidney failure. Breast cancer, colorectal cancer, and Alzheimer’s are only some of the other conditions that previous research has linked with red meat intake.