Plant-based diet may help lower heart disease risk: Study

Diets with reduced sulfur amino acids -- which occur in protein-rich foods, such as meats, dairy, nuts, and soy -- are associated with a decreased risk for cardiovascular disease, according to a study published on Monday. Amino acids are the building blocks of proteins. A subcategory, called sulfur amino acids, including methionine and cysteine, play various roles in metabolism and health.

"For decades, it has been understood that diets restricting sulfur amino acids were beneficial for longevity in animals," said John Richie, a professor at Pennsylvania State University in the US. "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 said.

The study, published in the journal Lancet EClinical Medicine, examined the diets and blood biomarkers of more than 11,000 participants from a national study in the US. It found that participants who ate foods containing fewer sulfur amino acids tended to have a decreased risk for cardiometabolic disease based on their bloodwork.

The researchers compiled a composite cardiometabolic disease risk score based on the levels of certain biomarkers in participants' blood after a 10-16 hour fast including cholesterol, triglycerides, glucose, and insulin. "These biomarkers are indicative of an individual's risk for disease, just as high cholesterol levels are a risk factor for cardiovascular disease," Richie said.

"Many of these levels can be impacted by a person's longer-term dietary habits leading up to the test," he said. The researchers found that higher sulfur amino acid intake was associated with a higher composite cardiometabolic risk score after accounting 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. "Meats and other high-protein foods are generally higher in sulfur amino acid content," said Zhen Dong, lead author of the study.

"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," Dong said. While the study only evaluated dietary intake and cardiometabolic disease risk factors at one point in time, the association between increased sulfur amino acid intake and risk for the cardiometabolic disease was strong, she said.