Casein and whey are both proteins found in milk. They both contain all the essential amino acids, although they have slightly different amino acid profiles. Notably, whey protein has a higher leucine content (about 11-12% versus casein’s 9%).[1]
Because of its chemical structure, casein does not combine well with acids. When it comes into contact with stomach acid, it becomes gel-like in consistency, and this coagulated substance is the reason that casein is digested so slowly. Whey protein is absorbed more quickly, releasing amino acids into the system within an hour.[2][3] These differences can affect the way we use these protein supplements. For example, taking a whey protein supplement after training makes sense, as the body can immediately use the amino acids for muscle growth and recovery. However, casein is a better choice prior to sleeping, since it gives the body a continuous supply of amino acids while fasting for (hopefully) 8 hours while sleeping.[4]
Some people prefer the texture of whey protein as a drink, since it mixes more easily with water. Both proteins are good for muscle growth and recovery, and both can increase satiety.[5][6][7]
References
- ^van Vliet S, Burd NA, van Loon LJThe Skeletal Muscle Anabolic Response to Plant- versus Animal-Based Protein ConsumptionJ Nutr.(2015 Sep)
- ^Steininger K, Wodick RE, Späte WChondropathia patellae--study of the femoropatellar joints of healthy, athletic children.Sportverletz Sportschaden.(1990-Jun)
- ^Antonio J, Ellerbroek A, Peacock C, Silver TCasein Protein Supplementation in Trained Men and Women: Morning versus EveningInt J Exerc Sci.(2017 May 1)
- ^Kim JPre-sleep casein protein ingestion: new paradigm in post-exercise recovery nutrition.Phys Act Nutr.(2020-Jun-30)
- ^Jäger R, Kerksick CM, Campbell BI, Cribb PJ, Wells SD, Skwiat TM, Purpura M, Ziegenfuss TN, Ferrando AA, Arent SM, Smith-Ryan AE, Stout JR, Arciero PJ, Ormsbee MJ, Taylor LW, Wilborn CD, Kalman DS, Kreider RB, Willoughby DS, Hoffman JR, Krzykowski JL, Antonio JInternational Society of Sports Nutrition Position Stand: protein and exerciseJ Int Soc Sports Nutr.(2017 Jun 20)
- ^Line Q Bendtsen, Janne K Lorenzen, Nathalie T Bendsen, Charlotte Rasmussen, Arne AstrupEffect of dairy proteins on appetite, energy expenditure, body weight, and composition: a review of the evidence from controlled clinical trialsAdv Nutr.(2013 Jul 1)
- ^Pal S, Radavelli-Bagatini S, Hagger M, Ellis VComparative effects of whey and casein proteins on satiety in overweight and obese individuals: a randomized controlled trial.Eur J Clin Nutr.(2014-Sep)