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Protein

Also known as: protein, whey protein, casein protein, plant protein, essential amino acids (EAA), Protein

Overview

Protein is a crucial macronutrient essential for various bodily functions, including tissue repair, muscle growth, immune function, and hormone production. It is derived from both animal sources, like meat, dairy, and eggs, and plant-based sources such as legumes, nuts, and seeds. Available in supplements, common forms include whey, casein, and various plant powders. Protein supports muscle recovery and enhances athletic performance by providing essential amino acids necessary for optimal body functioning. Current research indicates pronounced benefits of protein supplementation, particularly in promoting muscle strength and mass during resistance training, making it particularly advantageous for the elderly, athletes, and active individuals focused on recovery and performance maximization.

Benefits

Extensive evidence supports that protein supplementation significantly enhances muscle strength and size, especially post-resistance training. Meta-analyses report an average increase of 2.49 kg in one-repetition maximum strength and 0.30 kg in fat-free mass associated with protein intake. Endurance athletes also see performance improvements with a standardized mean difference of 0.31. Specific populations, such as the elderly and undernourished individuals, experience notable gains in muscle strength and physical function through regular protein and EAA supplementation. These positive outcomes clearly emerge across multiple studies, particularly with supplementation spanning six weeks or longer in conjunction with exercise programs.

How it works

Protein supplementation enhances muscle protein synthesis (MPS) vital for muscle repair and growth. By providing essential amino acids, it stimulates intracellular pathways such as the mechanistic target of rapamycin (mTOR), a key regulator of muscle growth. Different protein types present varying absorption rates; for instance, whey protein is rapidly metabolized, making it most effective when ingested post-exercise. This mechanism supports muscle health and aids various metabolic processes throughout the body.

Side effects

Protein supplementation is generally safe for healthy individuals adhering to recommended limits. Potential side effects primarily include gastrointestinal issues like bloating, gas, and stomach cramps, especially at high dosages or with certain protein types. Less than 5% of users may experience kidney strain or discomfort, particularly those with existing conditions. Severe allergic reactions are rare, occurring in less than 1% of users, mostly from sources like milk or soy. While no significant drug interactions have been noted with protein use, individuals with kidney disorders are advised to consult a healthcare provider before starting supplementation due to risks associated with increased protein intake. Most individuals tolerate protein supplements well, although personal health factors should guide usage.

Dosage

For optimal muscle growth and strength improvements, a daily protein intake of 1.2-1.6 g/kg is recommended. Those aiming specifically for muscle mass gains may benefit from dosages between 1.6 and 2.2 g/kg/day, with diminishing returns observed beyond 1.62 g/kg/day for resistance exercise benefits. Although no universally accepted upper limit is established, intakes above 2.3 g/kg/day could lead to gastrointestinal issues and possible kidney strain. Timing is crucial; protein intake post-exercise and pre-sleep maximizes recovery and muscle protein synthesis. Furthermore, the absorption rates of specific protein types, like whey and EAAs, affect their efficacy, suggesting spreading protein intake throughout the day enhances overall results.