Recently published study (unhappily, only with mice as proband) showed increased risk for unstable plaque buildup in the arteries under high protein diet.
The researchers studied mice fed a high-fat diet, some of the mice received a high-fat diet that was also high in protein. Third group were fed a high-fat, low-protein diet for comparison. Compared to human, mice were fed with approximattely tripple amount of recommended protein intake, protein went from 15% to 46% of calories for the high-fat and high-protein group. These mice developed about 30% more plaque in the arteries than mice on the high-fat, normal-protein diet. The mice on the high-protein group did not gain weight. Important finding was that plaques in the arteries on the high protein diet were extremely unstable and prone to rupture. Especially amino acids leucine and arginine were most potent to activate a special protein called mTOR and stimulate plaque instability. These amino acids were found primarily in red meat. They shut down macrophages (a type of white blood cell of the immune system, that engulfs and digests cellular debris) from their cleanup tasks in blood vessels. Plant based protein diet with different amino acid contents may have another effect on plaque complexity, researchers say.
While athletes do need more protein, most people already consume more protein than is required. This means that athletes don’t necessarily need to increase protein consumption in order to meet recommendations – there are many foods that contain protein that are often not be thought of as a source of protein. Most athletes can get the recommended amount of protein through food alone, without the use of supplements. Protein powders and supplements are great for convenience and can be useful when athletes need immediate protein right after a workout and don’t have time for a meal.
Xiangyu Zhang et al. High-protein diets increase cardiovascular risk by activating macrophage mTOR to suppress mitophagy. Nature Metabolism, 2020; 2 (1): 110 DOI: 10.1038/s42255-019-0162-4