Diets with reduced protein may be key to lowering the risk for heart disease

Lower protein diets may lessen the risk for cardiovascular disease.


An average adult American consumes sulfur amino acids (SAA) at levels far above the Estimated Average Requirement (EAR). Many studies have suggested that higher levels of SAA intake may be associated with a variety of aging-related chronic diseases.

However, there are little data concerning the connection between SAA intake and chronic disease risk in humans.

A new study by the Penn State scientists sought to determine the associations between consumption of SAA and risk factors for cardiometabolic diseases.

Scientists examined the diets and blood biomarkers of more than 11,000 participants from a national study. They found that participants who ate foods containing fewer sulfur amino acids tended to have a decreased risk for cardiometabolic disease based on their bloodwork.

John Richie, a professor of public health sciences at Penn State College of Medicine, said“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.”

Scientists evaluated the data from the Third National Examination and Nutritional Health Survey. They gathered a composite cardiometabolic disease risk score based on the levels of specific biomarkers in participant’s blood following a 10-16 hour fast, including cholesterol, triglycerides, glucose, and insulin.

These biomarkers are indicative of an individual’s risk for disease. Many of these levels can be impacted by a person’s longer-term dietary habits leading up to the test.

Participants were excluded from the study if they reported having either congestive heart failure, heart attack, or a reported change in diet due to a heart disease diagnosis. Individuals were also omitted if they reported dietary intake of sulfur amino acids below the estimated average requirement of 15 mg/kg/day recommended by the Food and Nutrition Board of the National Academy of Medicine.

To meet this daily requirement, a person weighing 132 pounds might eat, throughout a day, a medium slice of bread, a half an avocado, an egg, a half cup of raw cabbage, six cherry tomatoes, two ounces of chicken breast, a cup of brown rice, three-quarters of a cup of zucchini, three tablespoons of butter, a cup of spinach, a medium apple, an eight-inch-diameter pizza and a tablespoon of almonds.

Dietary information was obtained from in-person 24-h dietary recalls with the use of a personal computer-based, automated, interactive data collection, and coding system. Nutrient intakes were then calculated using the U.S. Department of Agriculture Survey Nutrient Database.

After accounting for body weight, the researchers found that the average sulfur amino acid intake was almost two and a half times higher than the estimated average requirement.

Xiang Gao, associate professor and director of the nutritional epidemiology lab at Penn State University, said, “Many people in the United States consume a diet rich in meat and dairy products, and the estimated average requirement is only expected to meet the needs of half of the healthy individuals. Therefore, it is not surprising that many are surpassing the average requirement when considering these foods contain higher amounts of sulfur amino acids.”

Scientists found that higher sulfur amino acid intake was associated with a higher composite cardiometabolic risk. They also found that high sulfur amino acid intake was associated with every type of food except grains, vegetables, and fruit.

Zhen Dong, a lead author of the study and College of Medicine graduate, said, “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.”

“While this 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. The data supports the formation of a prospective, longitudinal study evaluating sulfur amino acid intake and health outcomes over time.”

The study was published in the journal Lancet EClinical Medicine.

Other co-authors of the study include Vernon Chinchilli, Raghu Sinha, Joshua Muscat, and Renate Winkels of Penn State College of Medicine.


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