Manufacturers of protein supplements are strongly offering them to many athletes who still consider protein as the most important nutrient. Protein supplements can be divided into two categories: the first includes whole protein - eggs, milk or soy protein, the second contains individual free amino acids or combinations thereof.
Whole-protein supplements are used to increase the total amount of protein in food, sometimes they are strengthened with separate amino acids. To satisfy the protein requirements, whole-protein supplements are not used, since the food contains a sufficient number of them. However, these supplements are convenient, especially for athletes with high calorie needs and do not have enough time for cooking and eating. Some additives are very compact, do not require freezing and are convenient for application in "hot" days. Some of them can be mixed with milk and provide up to half the protein requirement, others (protein powders) - with water and are suitable for athletes who do not tolerate lactose. Protein tablets or pills usually contain less protein than powders. Soluble mixtures for breakfast are a good alternative to expensive protein powders. Energy tiles containing a minimum of 7-14 g protein (1-2 ounces), contribute to the satisfaction of protein requirements and are easy to use. Athletes should be aware that some supplements contain an excessive amount of protein in a dose (over 50 g) and are not necessary.
Studies have shown that supplements containing small amounts of certain amino acids can improve performance by lowering lactate concentrations in muscles and blood. Large doses of these supplements do not improve the performance. Additives with some amino acids are risky, because they can cause metabolic imbalances, changes in the transmission of nerve impulses and even poisoning.
- Amino acids with branched chain
Fatigue of the central nervous system. Branched chain amino acids (ACRTs) -leucine, isoleucine and valine-were studied in connection with fatigue of the central nervous system. It is commonly believed that fatigue caused by excessive exercise has a muscular origin, but it arises in the brain. There is a theory that, during prolonged exertions, excess serotonin passes the blood-brain barrier and causes fatigue; some researchers describe this condition as overtraining. Amino acid tryptophan is a precursor of serotonin. During the load, the ACPTs from the skeletal muscles are oxidized, while their number decreases, and the amount of fatty acids in the blood increases, displacing tryptophan from the site of its bonding to plasma albumin and increasing the amount in the brain. When the ratio of tryptophan and ACRT increases, more serotonin enters the brain. Changing this ratio by increasing the amount of ACPT or carbohydrates can reduce the flow of tryptophan into the brain. This study confirms the opinion on the use of carbohydrates for changing the level of serotonin, but does not prove the effectiveness of ACRT to prevent fatigue.
A growth hormone. It is assumed that the amino acids arginine and lysine increase the synthesis of growth hormone, thereby inducing an anabolic effect accompanied by the growth of muscle mass.
Glutamine. Although glutamine is not an essential amino acid, some researchers believe that it is necessary in large doses during excessive loads. Glutamine is involved in immune reactions. In athletes with a syndrome of overtraining, the level of plasma glutamine is understated, which can worsen the immunity. A strained physical load without adequate recovery depletes glutamine stores, and the body is unable to synthesize glutamine with sufficient speed to reach a pre-load level. Glutamine can also be involved in the synthesis of muscle glycogen. Adequate glutamine content helps to enhance protein synthesis after exercise. Studies do not provide conclusive evidence supporting the use of glutamine supplements.
Two other protein-like additives that deserve attention are creatine and beta-hydroxy-beta-methylbutyrate. Both may contribute to the growth of muscle mass and strength, but whether their long-term use is safe is unknown.
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