Amino Acids in Meat, Milk May Raise Heart Disease Risk

We need amino acids to provide our bodies with the building blocks to make proteins, enzymes, and other important compounds.

However, new data has shown that eating sulfur-containing amino acids—mostly found in meat and milk—may increase our cardiovascular disease.

The findings of the new study were presented at the American Heart Association’s Epidemiology, Prevention, Lifestyle, and Cardiometabolic Health Conference.

What Are Sulfur-Containing Amino Acids?

Amino acids are found in protein-rich foods. The body needs them for building muscle, producing enzymes, and making or fixing DNA. Certain amino acids are also key players in protein structure and protein-folding pathways.

Four amino acids—methionine, cysteine, homocysteine, and taurine—have a chemical element called sulfur in them.

Our bodies need these amino acids for different reasons. For example, methionine helps prevent disorders of the hair, skin, and nails. It may also help protect the liver from the toxic effects of too much acetaminophen.

Potential Heart Health Risks

Consuming sulfur-containing amino acids may have some health risks.

For example, homocysteine has been linked to heart disease. High levels of homocysteine are also associated with an increased risk for stroke.

That said, there have not been many studies to look at whether regularly eating foods with sulfur-containing amino acids plays a direct role in heart disease risk and mortality.

The Study

To see if there could be a relationship between sulfur-containing amino acid intake and cardiac outcomes, researchers looked at data on 120,699 participants in the Nurses’ Health Study (1984–2016) and Health Professionals Follow-up Study (1986–2016).

The researchers assessed the participants’ dietary intake of sulfur-containing amino acids. The participants’ health outcomes were tracked over about 32 years to reveal the following findings:

• On average, participants consumed more than twice the recommended daily allowance of sulfur-containing amino acids (which is 19 mg/kg/day). Most of their intake came from eating beef, chicken, and milk.
• Higher sulfur-containing amino acid intake was significantly associated with a higher risk of heart disease, early death due to heart disease, and all-cause mortality for both men and women.
• Compared to people who ate the least amount of sulfur-containing amino acids, the people who consumed the most had a 12% increased yearly risk of developing heart disease and a 28% increased risk of early death from heart disease.
• Regardless of the participants’ age, body mass index (BMI), physical activity level, the ratio of dietary animal to plant protein, smoking, and alcohol consumption, high sulfur-containing amino acid intake was associated with more significant risks of heart disease and mortality.

Limitations to Keep In Mind

The prospective study included a lot of people who were followed over many years, which were strengths of the research. However, it also had some important limitations.

• The findings are preliminary, which means they have not yet been published in a peer-reviewed journal.
• Correlation does not equal causation. Just because a connection is observed between two things does not mean that one caused the other. More well-designed clinical trials are needed to see if there is an important causal link.
• The results are based on self-reported data from the participants, which can be unreliable if people misremember or inaccurately report information on purpose.
• The population in the study included mostly White people who were well-educated. Therefore, the results might not apply to other groups of people.

Should You Eat Less Meat?

Most sulfur-containing amino acids are animal products. If you’re a meat-eater and you’re worried about the possible health effects of these amino acids, know that you don’t necessarily have to go meat-free.

Michelle Routhenstein, MS, RDN, CDE, CDN, a New York-based cardiovascular registered dietitian, told Verywell that she often sees people get hyper-focused on one macronutrient or another when it comes to reducing their cardiovascular disease risk.

According to Routhenstein, what’s really needed is “macronutrient balance.” To that end, she recommends “choosing the appropriate quantity and the diversity of proteins, along with adding appropriate quantities of complex carbohydrates and heart-healthy fats to ensure nutrient adequacy and to protect your heart health.”

If you eat meat, you don’t necessarily have to stop. Instead, Routhenstein recommends adding other heart-healthy proteins, like chickpeas, lentils, tofu, and edamame, to your diet.

A Well-Balanced Diet

Elizabeth Shaw, MS, RDN, CPT, a California-based registered dietitian and the owner of ShawSimpleSwaps.com, told Verywell that “eating a well-balanced diet abundant in plant-based foods is important for lifelong health.”

According to Shaw, “we know well from other research that restriction of specific foods that are a part of many cultures, like meat, isn’t going to be realistic long-term.”

What’s more, meat can have a place in a diet that’s a blend of nutritious foods. For example, Shaw pointed out that beef offers “essential nutrients people need throughout their life stages.”

About three-quarters of Americans meet or exceed the recommendation for meats, poultry, and eggs. As such, they might be getting more sulfur-containing amino acids than is recommended.

Any food can be linked to negative health outcomes if you eat too much of it and don’t balance it out with the other nutrition that your body needs.

If you want to keep meat and other animal products in your diet, stick to the recommended servings: that’s no more than four ounces of meat and three dairy servings a day.