The study was led by Laila Al-Shaar an assistant professor of epidemiology at Penn State University College of Medicine in Hershey, Pennsylvania, and presented at the American Heart Association's Epidemiology and Prevention, Lifestyle and Cardiometabolic Health conference in Chicago.
According to new preliminary research, consuming too much food containing sulfur amino acids including methionine and cysteine, primarily found in proteins such as beef, chicken, and dairy may increase individual risk of cardiovascular disease and death.
Sulfur amino acids are essential for metabolism and overall health, but the average person in the United States consumes far more than needed as much as two and a half times the estimated average requirement.
The researchers analyzed data from 120,699 people in two long-term national studies, the Nurses’ Health Study and Health Professionals Follow-up Study. Participants completed detailed health questionnaires, including questions about their diets, every two to four years.
On average, participants ate more than twice the recommended daily amount of sulfur amino acids, mostly from beef, chicken and milk. After adjusting for other cardiac risk factors, the researchers found that, compared to those who ate the least, those who consumed the most sulfur amino acids had a 12% increased annual risk of developing cardiovascular disease and a 28% increased risk of dying from the condition over the 32-year study period. The results are considered preliminary until the full findings are published in a peer-reviewed journal.
The vast majority at least 94% of the participants were non-Hispanic white men and women, and because they were health professionals, their socioeconomic status may not represent the overall population. This means the results might not be generalizable to other groups, Al-Shaar said. So, other studies should include populations with different dietary behaviors, specifically those whose protein intake is primarily from plant sources, she said.
It also builds on a study Al-Shaar led as a postdoctoral research fellow in the Harvard T.H. Chan School of Public Health in Boston. Published in the BMJ in 2020, it suggested that substituting high-quality plant foods such as legumes, nuts or soy for red meat might reduce coronary heart disease risk in men.
Al-Shaar said people can get their estimated average requirement of sulfur amino acids – 15 milligrams per kilogram of body weight per day – through plant-based sources or fish. For a 150-pound adult, for instance, that would mean 1 cup of tofu and 1 cup of lentils a day. It can be also met by consuming a 3-ounce fillet of tuna.
The study also fits in with current research about metabolism and specific biomarkers, known as “metabolomics,” a tool that supports precision medicine tailored to a specific patient.
The new research adds focus to the overall way adults eat in the U.S. and highlights that a healthy diet should incorporate more fruits and vegetables, said Judith Wylie-Rosett, a professor of epidemiology and population health at Albert Einstein College of Medicine in New York.