Whey protein falls into the category of protein powders that are animal-derived, as it is a milk protein. Whey is high in protein and is more quickly digested than the other milk protein casein. After digestion it is quickly broken down into essential amino acids, including the branched chain amino acid leucine that has been shown in studies to be important in muscle growth. Since it is quickly digested it is more readily available for protein synthesis. Studies using whey protein supplementation have shown increases in muscle protein synthesis, increased muscle mass and strength, improved recovery, and even anti-inflammatory benefits. The timing of whey protein intake also appears to be an important factor. When whey is ingested more immediately following a training session, there is a greater response in muscle protein synthesis (1). Kinetic studies indeed have shown that whey protein stimulates postprandial muscle synthesis better than casein protein (2). In another study, consumption of two-servings of beef protein isolate or whey resulted in significant gains in lean body mass over time, which was greater than gains from exercise alone (5). Even in sedentary individuals, whey protein supplementation may improve muscle recovery, at least compared to placebo (4).
Whey protein powders also come in different varieties, including isolate, concentrate, and hydrolysate.
Whey concentrate has not undergone any purification processes and contains protein, lactose, fat, and cholesterol. If you have zero gastrointestinal issues you may do fine with this product, and it does tend to be the cheapest. However, many people with even mild digestive issues may need a product with a lower percentage of lactose.
Isolate refers to a purification process where non protein components are removed from the whey concentrate to give a higher percentage of protein per serving. This is mainly removing the carbohydrate portion , notably lactose, from the whey. This means you are getting more protein and less carbohydrate, fat, and cholesterol. Isolate seems to be very beneficial in those having digestive issues or lactose intolerance.
Whey hydrolysate, or “hydrolyzed” whey means the product has been broken down into smaller groups of amino acids to improve the speed of digestion. The increase is only minimal, however, as whey protein is already quickly digested. This is, however, a good way for a company to charge you more under the guise of faster digestion. It typically isn’t necessary, but if you like paying more money for no real additional benefit this could be great for you.
Additionally, there are blends that contain both whey concentrate and isolate. This will still retain some of the lactose, cholesterol, and fat, but at a lower percentage than pure whey concentrate. Basically the biggest thing is to make sure you are reading the labels and understanding what type of product you are buying. Protein, carbohydrates, and fat will always be listed along with the ingredients so that this can be worked into your macros. Someone doing an intense workout with a higher amount of cardio may benefit from a supplement with some extra carbohydrates to replenish after a workout.
Casein is also a milk derived protein, however it is digested more slowly due to a complex interaction with stomach acids. This makes casein the preferred supplement in situations when a slow release of nutrients is beneficial. For this reason, it is often marketed as a supplement to take before bedtime when you will be going 7-10 hours without eating. Since it is a slowly digested protein it is theoretically conceived that it would not be as beneficial immediately after exercise when you are looking to get those building block amino acids to your broken down muscles quickly. As noted above, this does appear to be true based on kinetic studies (2). Many other studies have shown that whey is more effective than casein at increasing muscle protein synthesis and strength immediately following exercise. There was a study, however, that did show casein had an advantage over whey in improving overall body composition during resistance training when coupled with calorie restriction. Many athletes in training are not reducing calories so this would not apply, but in those looking to try to lose weight while maintaining lean body mass this is an interesting finding. Since casein is digested more slowly, it can be thought of as anti-catabolic, while whey is more anabolic in nature. So even though casein may not have the edge in muscle protein synthesis after an intense workout, it is beneficial in preventing muscle breakdown when your body is in a fasting states-such as overnight or during a busy day when you have to go long periods without eating.
These same studies do show that casein is more beneficial for protein synthesis than vegetable derived proteins such as soy and wheat. Also, since casein is more slowly digested it is beneficial in decreasing muscle breakdown and maintaining muscle mass.
Soy is the only plant based protein that contains all nine essential amino acids. It is isolated from soybean meal to produce a highly concentrated protein powder. While it is a complete protein, it does contain lower amounts of lysine than whey, and lysine has shown in studies to be important in muscle protein synthesis. Additionally, it has a much lower biologic value than whey protein, meaning that a lower amount is available for use after being absorbed. Soy also lacks methionine, an important amino acid that helps decrease inflammation and acts as an antioxidant. However, it does contain isoflavones that contribute to decreasing inflammation, so this may offset. Over the years there have been questions raised about the safety of soy and possible negative side effects it could produce due to containing phytoestrogens. Since this is similar in chemical structure to estradiol, theoretically this could raise estrogen levels and decrease testosterone levels. However, studies have shown that this does not appear to occur at any significant level in humans.
Studies comparing soy to whey protein in aiding muscle growth have shown that supplementing with either is beneficial. A study involving 20 male athletes found daily supplementation of soy protein, whey, or a soy-whey blend all resulted in an increase in lean body mass and did not negatively affect testosterone or estradiol levels when combined with a weight training program (9).
Pea protein is one of the newer supplements on the block. It is plant derived from the yellow split pea and contains high amounts of eight of the nine essential amino acids. It is lacking methionine, however, which as noted above is an amino acid with antioxidant characteristics. Importantly, however, it is rich in branched chain amino acids which are crucial to muscle protein synthesis. While there are far fewer studies on pea protein out there, one promising study showed that participants ingesting pea protein had similar gains in biceps muscle hypertrophy compared to those ingesting whey protein during a 12 week period. Both groups had significantly improved muscle growth compared to placebo (6). This could be a useful alternative to whey protein in those that are following vegan or vegetarian diets or have GI issues with other supplements.
Yes, I know when you think hemp you think of marijuana. While related, there are only extremely trace amounts of THC in hemp. Hemp is also rich in beneficial omega-3 fatty acids. However it does not contain all of the essential amino acids, and unfortunately is very low in important muscle building amino acids lysine and leucine. It is also higher in fat and calories. It is well digested, however there are not many controlled studies out there comparing it to other protein supplements. Based on its composition as noted above it would be further down on my list of protein supplements to use, at least until further studies are done.
brown rice protein
Brown rice protein is another plant based protein, that, despite being around for quite some time, there is little research on presently. It is not a complete protein as it does not contain the essential amino acid lysine, a very important amino acid in muscle building. One short, eight week study did show similar benefits between brown rice and whey protein in regards to strength, recovery, and body composition in a trial involving 24 college aged males enrolled in a resistance training program. Unfortunately there was no placebo group in this study (7). Again, this could be a potential supplement for those aiming to avoid animal based protein supplements, however there is little research to support its benefits.
There are some brands out there that blend together the different plant based proteins-pea, brown rice, hemp, and even quinoa and chia seed-to make a dairy free, animal product free, soy free blend that contains all the essential amino acids. These blends typically have a higher amount of fiber and thus are digested and absorbed more slowly. This could theoretically delay amino acid use for muscle protein synthesis.
One recent, small study provided resistance-trained young men with 60 grams of either whey protein, a pea-rice protein blend or a pea-rice protein blend with supplemental enzymes to speed up the rate of digestion. They found that adding digestive enzymes to the mixed-vegetable protein supplement led to a faster appearance of amino acids in the blood that was comparable to whey protein (8). However this appearance in the blood alone does not necessarily equate to its muscle building capabilities. Theoretically, however, since these blends contain all nine essential amino acids it is postulated that they would have similar benefits to whey protein when combined with exercise and weight training.
Based on the research, I do believe that whey protein has the advantage in aiding muscle growth as a nutrient source following a workout. It is digested quickly, peaks in the blood, and can be used for muscle protein synthesis in the crucial period following a workout where muscle breakdown has occurred. In an especially intense workout, it is also important to combine this with a carbohydrate source as well as this will replenish glycogen stores and allow insulin to rise enough to allow nutrients to move into your muscle cells to do their work. Casein protein would be a close second, although I do believe this is more beneficial as an anti-catabolic protein source and great for including in a bedtime snack or between meals. I have most recently been using supplements off the Idealfit line and have really been happy with the results. I also really like the Optimum Nutrition Gold Standard Whey which has a great track record with fitness and body building enthusiasts.
For those that are following vegan and vegetarian diet plans, there are numerous plant based proteins out there. Soy is probably at the top of my list right now due to the fact that the most research has been done on this and it is a complete protein. While there are still some fears out there about it affecting hormone levels this appears to really not be a factor, at least at the recommended intake levels. However, research is always changing and will need to continue to be evaluated. Pea protein appears to show some promise, although it does not have a complete amino acid profile. Vegan blends that contain all nine essential amino acids theoretically should show similar results to whey protein, however there is not much research out there on this yet.
I will always advocate whole food sources when available to fuel workouts and to aid in training gains, however I do feel that supplements play a crucial role in any training program when used correctly.
1.Hulmi JJ, Lockwood CM, Stout JR. Effect of protein/essential amino acids and resistance training on skeletal muscle hypertrophy: A case for whey protein. Nutrition & Metabolism. 2010;7:51.
2. Pennings,B, Yves, Boirie, Senden, J, Gijsen A, Kuiper H, Loon, L. Whey protein stimulates postprandial muscle protein accretion more effectively than do casein and casein hydrolysate in older men. The American Journal of Clinical Nutrition, Volume 93, Issue 5, 1 May 2011, Pages 997–1005, 02 March 2011
3. Cribb PJ, Williams AD, Carey MF , Hayes A. The effect of whey isolate and resistance training on strength, body composition, and plasma glutamine.Int J Sport Nutr Exerc Metab. 2006 Oct;16(5):494-509.
4. Buckley JD,Thomson RL, Coates AM,Howe PR,DeNichilo MO,Rowney MK. Supplementation with a whey protein hydrolysate enhances recovery of muscle force-generating capacity following eccentric exercise. J Sci Med Sport. 2010 Jan;13(1):178-81.
5. Sharp M, Shields K, Lowery R, et al. The effects of beef protein isolate and whey protein isolate supplementation on lean mass and strength in resistance trained individuals – a double blind, placebo controlled study. Journal of the International Society of Sports Nutrition. 2015;12(Suppl 1):P11. doi:10.1186/1550-2783-12-S1-P11.
6. Babault N, Païzis C, Deley G, et al. Pea proteins oral supplementation promotes muscle thickness gains during resistance training: a double-blind, randomized, Placebo-controlled clinical trial vs. Whey protein. Journal of the International Society of Sports Nutrition. 2015;12:3. doi:10.1186/s12970-014-0064-5.
7. Joy JM, Lowery RP, Wilson JM, et al. The effects of 8 weeks of whey or rice protein supplementation on body composition and exercise performance. Nutrition Journal. 2013;12:86. doi:10.1186/1475-2891-12-86.
8. Minevich J, Olson MA, Mannion JP, et al. Digestive enzymes reduce quality differences between plant and animal proteins: a double-blind crossover study. Journal of the International Society of Sports Nutrition. 2015;12(Suppl 1):P26. doi:10.1186/1550-2783-12-S1-P26.
9.Kalman, D., Feldman, S., Martinez, M., Krieger, D. R., & Tallon, M. J. (2007). Effect of protein source and resistance training on body composition and sex hormones. Journal of the International Society of Sports Nutrition, 4(1), 4