Protein powder: whey, casein, plant-based

A protein powder is a dietary protein isolated from milk (whey, casein), egg or plants (pea, rice, soy, hemp), dried and flavoured. It provides the same amino acids as a meal, faster and without the rest. The ISSN (International Society of Sports Nutrition) describes supplementation as a practical way to reach the desired quantity and quality, not as superior to whole foods. People buy it for muscle mass, recovery and satiety.

• Whey concentrate: 29 to 80% protein by dry weight according to the ISSN, the rest being mostly lactose and fat.
• Whey isolate: more than 90% protein, with lactose and fat largely removed by ion exchange or microfiltration, which makes it usable by people who are lactose intolerant according to Hoffman and Falvo.
• Hydrolysate: protein pre-digested into di-, tri- and tetrapeptides; the ISSN does not separate its results from those of the isolate. Casein: clots in the stomach and digests more slowly; 30 to 40 g before bedtime increase overnight protein synthesis (ISSN).
• Plant-based (pea, rice, soy, hemp): essential amino acids at 26 ± 2% of the protein versus 37 ± 2% for animal proteins, lower leucine (5.1% for hemp versus 11% for whey), with lysine and methionine often limiting (Gorissen 2018).

• ISSN: 1.4 to 2.0 g/kg per day for most people who train; 0.25 g/kg or 20 to 40 g per serving, with 700 to 3,000 mg of leucine, every 3 to 4 hours. Morton: gains attributable to the supplement of 0.30 kg of lean mass and 2.49 kg of strength (1RM) over the length of a program, smaller with age.
• Health Canada (Workout Supplements monograph): up to 90 g per day of proteins and amino acids; above 30 g per day, the statements "consult if you have a liver or kidney disorder" and "gastrointestinal discomfort possible".
• Kidney: the Devries meta-analysis (28 trials, 1,358 healthy adults) finds no difference in the change in glomerular filtration rate between high and normal protein intakes. The Australian Institute of Sport classes isolated protein among the sports foods in its Group A.

Any time of day, aiming for the daily total split into 3 to 4 servings; after training remains practical, not mandatory. Casein finds its place before bedtime.

A chicken breast, a Greek yogurt, eggs or lentils do the same job with the micronutrients on top; the ISSN points out that an active person can meet their needs with whole foods.

Sources

• Jäger et al., ISSN position stand: protein and exercise, JISSN 2017
• Morton et al., A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults, BJSM 2018
• Devries et al., Changes in Kidney Function Do Not Differ between Healthy Adults Consuming Higher- Compared with Lower- or Normal-Protein Diets, Journal of Nutrition 2018 (abstract read via Europe PMC)
• Gorissen et al., Protein content and amino acid composition of commercially available plant-based protein isolates, Amino Acids 2018
• Hoffman and Falvo, Protein: Which is Best?, Journal of Sports Science and Medicine 2004
• Proteins and Minerals in Whey Protein Supplements, Foods 2023
• Comparative study of the most commonly used methods for total protein determination in milk, Frontiers in Nutrition 2022
• Bandara et al., A human health risk assessment of heavy metal ingestion among consumers of protein powder supplements, Toxicology Reports 2020 (abstract read via EPA HERO)
• Health Canada, natural health product monograph, Workout Supplements
• NIH Office of Dietary Supplements, Dietary Supplements for Exercise and Athletic Performance (Health Professional)
• Australian Institute of Sport, Sports Supplement Framework, Group A

Educational information, drawn from the sources above. It does not replace the advice of a health professional, who remains the reference for your situation, your medications, pregnancy or breastfeeding.