Why Eating This Much Protein Can Be Bad for Your Heart Health

Why Eating This Much Protein Can Be Bad for Your Heart Health – Protein, the building block of life, plays a crucial role in our health. From building and repairing tissues to powering vital bodily functions, it’s an essential nutrient we all need. But recent research suggests that when it comes to protein intake, too much of a good thing might pose risks to heart health. This article, informed by the latest scientific findings and expert recommendations, aims to navigate this complex topic, helping you make informed choices for optimal cardiovascular well-being.

Why Eating This Much Protein Can Be Bad for Your Heart Health: Striking the Balance for Optimal Well-being | Stock Photo
Why Eating This Much Protein Can Be Bad for Your Heart Health: Striking the Balance for Optimal Well-being | Stock Photo

Understanding the “High Protein” Threshold: Beyond the Gram Counting

So, how much protein is considered “high intake”? The answer isn’t as simple as a single number. While the Recommended Dietary Allowance (RDA) for adults sits around 0.8 grams per kilogram of body weight, recent research suggests a potential link between heart health concerns and exceeding 22% of daily calories from protein. This translates to roughly 180 grams of protein for someone consuming 2,000 daily calories. However, it’s crucial to remember that individual needs can vary depending on factors like activity level, age, and health status.

To reach their conclusions, the researchers used human trials along with experiments involving mice and cells in Petri dishes. The human studies had a total of 23 participants.

Researchers used two different study set-ups for the human studies. Both involved asking participants to have two liquid meals – one with standard protein and one with high protein – about one to two weeks apart.

The first set-up involved 14 participants. The standard meal had 10% of total energy as protein, 17% as fat, and 73% as carbohydrates. The high protein meal consisted of 50% of energy from protein, 17% as fat, and 33% carbohydrates.

The second setup involved nine participants and was designed to mimic a “real-world” scenario. In this setup, the standard meal was representative of a person’s average protein intake and had 15% of total energy as protein, 35% as fat, and 50% as carbohydrates. The high protein meal represented the upper quartile of protein intake and consisted of 22% of energy from protein, 30% as fat, and 48% carbohydrates.

The scientists noted that leucine is an amino acid that contributes to the development and worsening of atherosclerosis. They found that higher dietary protein intake, specifically intake of more than 25 grams of protein per meal or 22% of daily energy requirements, led to higher leucine levels that activated a specific pathway in immune cells that is associated with atherosclerosis.

The second part of the study involved mice.

The researchers first created diets for the mice with graded protein contents that mimicked the average (15%) and high (22%) protein intake for a typical adult living in the United States.

They reported similar results to the human studies.

They added that the same pathway was activated in mice receiving more than 25 grams of protein per meal, or 22% of total energy intake and that these mice were also more likely to promote atherosclerosis and cardiovascular disease.

The Study Behind the Headlines: Unveiling the Connection

A 2024 study published in Nature Metabolism, led by researchers at the University of Pittsburgh, shed light on the potential link between high protein intake and atherosclerosis, the build-up of plaque in arteries that increases the risk of heart disease. The study, involving both human participants and cell experiments, observed that consuming a high-protein diet (22% of calories) compared to a standard-protein diet (10% of calories) resulted in:

  • Increased levels of trimethylamine-N-oxide (TMAO): This metabolite, produced by gut bacteria when digesting protein, has been linked to increased risk of heart disease and stroke.
  • Changes in gut microbiome: The high-protein diet led to a shift in gut bacteria composition, potentially favoring those that produce more TMAO.
  • Increased stress on the kidneys: High protein intake can put extra strain on the kidneys, potentially impacting overall health.

However, it’s important to acknowledge the limitations of the study, such as its small sample size and observational nature, which means it cannot establish direct cause-and-effect. Further research is needed to fully understand the complex interplay between protein intake, gut bacteria, and heart health.

Conclusions from the protein diet and atherosclerosis study

The researchers conclude that high protein intake can contribute to atherogenesis.

The authors suggest that people approach high protein diets cautiously and that dietary guidelines are revised accordingly.

The authors note the recommendation from several organizations is that protein intake be about 11% of daily energy requirements to maintain nitrogen balance.

“High protein diets are very popular with the public, used for weight loss, bodybuilding, and an overall healthy lifestyle. For many years, reports in the research world using experiments in animal models showed that high protein diets can increase cardiovascular disease (also called atherosclerosis or hardening of the heart arteries), but no one knew why,” said Dr. Babak Razani, a professor of medicine at the University of Pittsburgh and one of the authors of the study. “In our previous 2020 paper, we used mouse models to define the mechanism for this by showing that protein ingestion activates macrophages, an immune cell that is a key driver of atherosclerosis, and we identified an important protein in the macrophages called mTOR that mediates this process.”

“Now, in the current study, we pin down the reasons why high protein diets are risky for our heart arteries,” Razani told Medical News Today. “First, we did several studies in humans to demonstrate that when people eat higher amounts of protein, our macrophages and the mTOR pathway get activated just like we found in animal models. Then, we identified, for the first time ever, the role of leucine – an amino acid highly enriched in animal-based proteins – as the driving force of atherosclerosis risk. Amino acids are the building blocks of proteins and there are 20 of them that make up any protein we ingest. But it is only leucine that is the bad actor in worsening the heart artery disease. We determined that eating meals containing about 22 percent kilocalories of protein is the threshold at which the protein and its leucine elevate risk.”

Beyond the Hype: Nuances and Individual Needs

While the study raises concerns about high protein intake, it’s important to remember that protein remains an essential nutrient for overall health. It plays a vital role in muscle building and repair, supports immune function, and contributes to satiety, helping with weight management.

The key lies in striking a balance:

  • Moderate protein intake: Aiming for the RDA or slightly above, depending on individual needs, can ensure you reap the benefits without exceeding healthy limits.
  • Quality over quantity: Choose lean protein sources like fish, poultry, beans, and lentils, and limit red meat and processed meats, which are often high in saturated fat and sodium.
  • Plant-based power: Incorporating plant-based proteins like legumes, nuts, and seeds into your diet offers additional fiber, vitamins, and minerals, further benefiting your heart health.
  • Individualized approach: Consulting a registered dietitian or healthcare professional can help tailor your protein intake based on your unique needs and health conditions.

Here are some actionable steps you can take to ensure your protein choices contribute to optimal heart health:

  • Prioritize lean protein sources: Opt for fish like salmon and tuna, skinless chicken and turkey breast, and lean cuts of beef or pork.
  • Limit red meat and processed meats: Aim for no more than two servings per week, and choose lean options when possible.
  • Embrace plant-based protein power: Include beans, lentils, chickpeas, tofu, tempeh, nuts, and seeds in your meals and snacks.
  • Cook smart: Choose healthy cooking methods like grilling, baking, or steaming to minimize added fat and unhealthy oils.
  • Don’t forget the veggies: Pair your protein with plenty of colorful vegetables, providing fiber, vitamins, and antioxidants essential for heart health.
  • Seek expert guidance: Consult a registered dietitian or healthcare professional for personalized advice on protein intake and a heart-healthy diet plan tailored to your needs.

Danahy recommends eating more plant protein (from foods instead of supplements) for anyone looking to add extra protein to their diet.

“Several studies have associated high animal protein diets with an increased risk of cardiovascular disease,” she said. “Protein from animal sources may also contain saturated fats or other compounds that can boost inflammation and promote heart disease.”

“On the other hand, protein supplied by plant sources contains antioxidants, fiber, and other nutrients that can reduce the risk of heart disease,” Danahy concluded. “Nuts, seeds, legumes, and vegetables all contain protein and other health-promoting compounds.”

Remember, achieving optimal heart health requires a holistic approach. While protein intake is an important factor, it’s just one piece of the puzzle. By combining mindful protein choices with a balanced diet, regular physical activity, and stress management, you can empower yourself to build a strong foundation for a healthy and vibrant life.