Evanston, IL, and Pennsylvania—Eating red meat and processed meat drives risk of heart disease up, according to new research from Northwestern University and Cornell—and eating a plant-based diet drops that risk, according to separate research from Penn State.
The study from Northwestern and Cornell, published in JAMA Internal Medicine, pooled together a diverse sample from six cohort studies, included long follow-up data up to three decades, adjusted a comprehensive set of confounders, and conducted multiple sensitivity analyses. The study included 29,682 participants. Diet data was drawn from participants, who reported what they had eaten for the previous year or month.
- Eating two servings of red meat, processed meat, or poultry per week was linked to a 3-7% higher risk of cardiovascular disease and premature death.
- Eating two servings of red or processed meat per week was associated with a 3% higher risk of all causes of death.
- Eating two servings per week of poultry was associated with a 4% higher risk of CVD, but a press release notes that the evidence was not sufficient to make a clear recommendation regarding poultry intake, and that the relationship may have more to do with the cooking method than the chicken meat itself.
- There was no association between eating fish and CVD or mortality.
Victor Zhong, Assistant Professor of Nutritional Sciences at Cornell and Lead Study Author, said in the release: “Modifying intake of these animal protein foods may be an important strategy to help reduce the risk of cardiovascular disease and premature death at a population level.”
“Fish, seafood, and plant-based sources of protein such as nuts and legumes, including beans and peas, are excellent alternatives to meat and are under-consumed in the U.S.,” added coauthor Linda Van Horn, Professor of Preventative Medicine at Feinberg.
The second study, from Penn State, suggests that the issue may lie in sulfur amino acids. These amino acids—including methionine and cysteine—are found in protein-rich foods, including meats, nuts, and soy. They play various roles in metabolism and health, but the team of researchers found that the average American consumes almost 2.5 times more sulfur amino acids than the average requirement.
John Richie, Professor of Public Health Sciences at Penn State College of Medicine, said in a press release: “For decades it has been understood that diets restricting sulfur amino acids were beneficial for longevity in animals. This study provides the first epidemiologic evidence that excessive dietary intake of sulfur amino acids may be related to chronic disease outcomes in humans.”
Richie and his team examined the diets and blood biomarkers of more than 11,000 participants from the Third National Examination and Nutritional Health Survey and found that participants who ate foods containing fewer sulfur amino acids tended to have a decreased risk for cardiometabolic disease based on their bloodwork, whereas higher sulfur amino acid intake was associated with a higher composite cardiometabolic risk score. These findings account for potential confounders like age, sex, and history of diabetes and hypertension.
They also found that high sulfur amino acid intake was associated with every type of food except grains, vegetables, and fruit.
Zhen Dong, Lead Author and graduate of the College of Medicine, said in the release: “Meats and other high-protein foods are generally higher in sulfur amino acid content. People who eat lots of plant-based products like fruits and vegetables will consume lower amounts of sulfur amino acids. These results support some of the beneficial health effects observed in those who eat vegan or other plant-based diets.”
She also noted that while this study only evaluated dietary intake and cardiometabolic disease risk factors at one point in time, the association between sulfur amino acid intake and risk for cardiometabolic disease was strong. The data, she said, supports the formation of a prospective, longitudinal study evaluating sulfur amino acid intake and health outcomes over time.