More proteins in the diet may raise the risk of heart disease and death as they are the primary source of sulfur amino acids.

According to an early study, eating too many foods containing sulfur amino acids – mostly found in proteins such as beef, chicken, and dairy – may raise a person’s risk of cardiovascular disease and death.

Sulfur amino acids are necessary for metabolism and overall health, but the average American consumes significantly more than is required — up to two and a half times the recommended amount.

“This may provide part of the reason why people who consume diets that emphasize healthy plant foods have lower rates of cardiovascular disease than those who eat large amounts of meat and dairy foods,” says Laila Al-Shaar, lead author of the study.

The Nurses’ Health Study and the Health Professionals Follow-up Study, both long-term nationwide investigations, yielded data from 120,699 individuals. Every two to four years, participants filled out extensive health questionnaires, which included information about their meals.

Participants consumed more than double the daily recommended quantity of sulfur amino acids, largely from beef, poultry, and milk, on average. After controlling for other cardiac risk factors, the researchers discovered that those who consumed the most sulfur amino acids had a 12 percent higher annual risk of developing cardiovascular disease and a 28 percent higher risk of dying from it over the 32-year study period than those who consumed the least. Until the entire findings are published in a peer-reviewed journal, the findings are considered preliminary.

The vast majority of the participants – at least 94 percent – were non-Hispanic white men and women, and their socioeconomic position may not reflect the general community because they were health professionals. According to Al-Shaar, this indicates the findings may not be applicable to other groups. As a result, she believes that further research should include groups with varying dietary habits, particularly those whose protein intake is primarily from plant sources.

Restricting certain types of amino acids – particularly methionine and cysteine – has been shown in several animal studies over the last few decades to slow the aging process and help animals live longer, but translating those advantages to humans has been difficult.

A study published in 2020 in The Lancet’s eClinicalMedicine journal by the same Penn State research group associated increased sulfur amino acid consumption with an increased risk of cardiometabolic disease. However, it was based on estimated diets from respondents who only filled out one or two diet questionnaires in the prior 24 hours. This current study expands on that work by using long-term diet data gathered through repeated food frequency surveys as well as health outcome data.

It also draws on a study Al-Shaar led at the Harvard T.H. Chan School of Public Health in Boston as a postdoctoral research fellow. It was published in the BMJ in 2020, and it claimed that replacing red meat with high-quality plant foods like legumes, almonds, or soy could reduce the risk of coronary heart disease in males.

People can acquire their estimated daily requirement of sulfur amino acids – 15 milligrams per kilogram of body weight – from plant-based sources or fish, according to Al-Shaar. For a 150-pound adult, this would equate to 1 cup tofu and 1 cup lentils each day. It can also be obtained by eating a 3-ounce tuna fillet.

“Since red meat has been found to be associated with worse health outcomes,” she adds, “it would be better to focus on healthier sources of proteins for meeting the average requirement of sulfur amino acids.”

According to Judith Wylie-Rosett, a professor of epidemiology and population health at Albert Einstein College of Medicine in New York, the new research brings attention to the general way adults consume in the United States and emphasizes that a balanced diet should include more fruits and vegetables.

“We all need to look at dietary patterns because the American dietary pattern is far from the recommendations,” adds Wylie-Rosett, who was not involved in the study. “But this study doesn’t give evidence that we should be focusing only on those two amino acids.”

“We’re moving toward precision nutrition,” says Wylie-Rosett. “We’re getting much more sophisticated in how we can look at nutrition. This was a fairly simple study but may help inform future studies about some of these more complex ways of looking at nutrition and metabolism.”

Source: Getty

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