Protein supplementation has been around for many years in an effort to provide the body with the essential amino acids it needs to build new muscle. Protein is a “perfect nutrient” because it supplies all of the necessary functions of food: building tissues, providing energy, and regulating metabolism. Trying to decide which protein to use and how much is a time consuming and mind boggling process. Fortunately, there are two proteins that are used extensively, and they are both derived from milk: whey protein and casein protein. The difference is that whey is a fast-acting protein and casein is a slow-acting protein. In other words, the body digests whey a lot quicker than casein. This is not to say that whey is a better source because it all depends on your ultimate goal and how you wish to use the product.
Whey proteins make up 20% of total milk proteins, and are extracted from the liquid whey of cheese, which comes from milk, during the manufacturing process. Whey has a higher content than casein of the branched-chain amino acids that promote protein synthesis. The fate of these amino acids is their use by the muscles during exercise, instead of being metabolized by the liver, hence resulting in immediate protein synthesis. Since when is fast-acting, this means that the body can digest, absorb, and distribute the amino acids throughout the blood very efficiently and very quickly. For this reason, it is used for bodybuilding because of its immediate effects on promoting the synthesis of muscle. The amount of time it takes to be digested, absorbed, released into the bloodstream, and the amino acids utilized for protein synthesis is about 1 hour. Consequently, its effects are not long-lasting. Whey is often used in the morning and after workouts to give it’s most beneficial and noticeable effects on muscle growth. If taken soon before a workout, whey will provide the branched-chain amino acids that the body increasingly needs during exercise to be used for muscle growth. After exercise, whey should be taken to restore the amino acids and help reduce the impact of fatigue.
Casein is another product from milk, and makes up 80% of the total milk protein content. When milk is processed using a heating method, the structure of the casein is denatured and broken down into smaller peptides. This forms a gel-like substance in the gut that results in a steady and gradual release of amino acids throughout the blood. The total effect from the amino acids in casein protein in the bloodstream can last up to 7 hours. Casein’s effects are for slower than whey’s because the release is so slow. This makes it better to prevent protein breakdown, rather than assist in protein synthesis. When protein is spared, the result is a net gain on protein synthesis, and therefore, the gain of muscle mass. Casein is best taken before bedtime because of its long-lasting effects. Throughout sleep, no food is being taken into your body, so protein breakdown is likely to occur. Casein will stop this breakdown from happening and not allow for your progress of working out and building muscle to be halted.
While both of these proteins are beneficial in their own right, the best results will be seen when taking a combination of the two. Whey and casein complement each other in how they affect protein in the body. Whey’s short-lasting effects make it ideal for protein synthesis, and casein’s long-lasting effects make it perfect for sustaining this protein synthesis by preventing the breakdown of protein. Use both in conjunction with each other. As with taking any protein supplement, you should check the amino acid profile and determine how it will help, or hurt, you. In this case, sustaining protein synthesis while preventing protein breakdown is a perfect match for muscle growth.