Plant-based proteins or animal proteins for muscle growth

Geschatte leestijd: 12 minuten

Researchers from Maastricht compared the effect of plant-based proteins and animal proteins on muscle growth. To what extent is the assumption true that animal proteins offer better results?

Review Body&Fit Vegan Perfection

Three weeks ago, a jar of protein was waiting for me at the office. Always nice, of course. “Chocolate was your flavor, right?” No, that’s just about the last flavor I would buy myself, but you don’t look a gift horse in the mouth. So, onto the ‘vegan proteins.’ As far as I can remember, this was a personal first. As a meat eater, there has never been any reason for it. There have been some discussions, but generally, it is assumed that animal proteins lead to more muscle mass than plant-based proteins. Personal favorites have always been whey and casein, to benefit from the effects of fast and slow proteins.

Milk proteins and animal suffering

I have never really felt morally burdened by that preference for proteins from milk. Although it falls under ‘animal’ proteins, I feel more that I should eat less meat from the perspective of animal suffering and the environment. But that’s not entirely fair, rather a little lie I tell myself to not feel bad about my post-workout shake and porridge in the morning. I then ignore animal suffering associated with the dairy industry. Calves being taken away from their mothers immediately. Cows standing on concrete their whole lives. A much shorter life, moreover, than in nature because with lower milk production, they go to slaughter. The same goes for the calves unlucky enough to be born male. For them, it’s about fattening them up and to the slaughterhouse for veal. Now, you could point out that whey, or serum, is a by-product of cheese production. ‘If it already occurs during cheese production, then it’s a waste not to use it.’ For casein, it is taken from the curd that would otherwise form cheese.

Milk proteins and the environment

So as long as I eat meat, I still find it (rightly or wrongly) a bit strange to avoid dairy. Porridge with water is also too disgusting for words. In this regard, the environmental aspect weighs a bit heavier for me personally. Proteins from dairy impose a higher burden on the environment than plant-based proteins. This also applies to proteins from meat. Getting off meat is quite difficult for me. However, when it comes to taste, there doesn’t need to be a difference between animal and plant-based proteins in powder form. So the only reason to choose the less environmentally friendly option is the thought that it adds more muscle mass to my body. For a long time, that has been reason enough. Wanting to get more muscular is after all the reason I use protein powder. However, as I get older, I increasingly wonder how I can justify such considerations later on. To my granddaughters, for example.

Plant-based proteins

So the timing was perfect in that regard. By literally having it shoved under my nose, the bar couldn’t have been lower. But before I could write the review, I had to delve more into plant-based proteins in general. I will post the review separately. First, let’s delve into the question of to what extent plant-based proteins are ‘inferior’ to animal proteins when it comes to muscle building. For this, I will gratefully use the work of researchers from UMC Maastricht published last year [1]. They compared various types of protein powder from multiple producers, including some Dutch ones. Their goal was to assess whether and to what extent plant-based proteins stimulate less muscle growth than animal proteins.

Protein concentration in protein powder

First, we need to distinguish between protein and protein powder. A protein powder will not contain 100% protein. Depending on the production process, this can be a low or high percentage. For example, whey concentrate contains up to 80% whey, alongside lactose (carbohydrates) and fats. Whey isolate contains up to 90% whey because it is further purified and contains less lactose and fats. For Maastricht’s research, all proteins were offered in isolate form. In the results below, it is noticeable, among other things, that the whey isolate was 72 to 84 percent in the different samples. Lower than you would expect. The powders with proteins from peas, brown rice, wheat, and potatoes showed a similar concentration. On average, the same applied to soy, although the differences were greater between the different samples (61 to 91 percent). The powders with proteins from oats, hemp, lupine, and corn showed considerably lower concentrations. The same applied to the powder with proteins from eggs. A nice addition from Maastricht is the comparison with a protein powder obtained from a (freeze-dried) Homo erectus steak (black bar). What do these figures say? First, that there are differences in the concentrations of powders with proteins from the same source. The concentration of proteins is not only related to inherent properties of the source (such as residual lactose in whey), but also to the production process. The latter does not necessarily say anything about the quality of the (pro teins in the) source itself. Considering this, we can conclude here that powders with proteins from multiple plant sources contain comparable protein concentrations to those from animal sources.

Price/quality

By the way, it doesn’t have to be a problem if a powder contains a (slightly) lower concentration of proteins. After all, you can simply take more of it. In that respect, it’s a matter of the higher price for larger doses versus the possible higher price of more purified powders. However, you should of course consider what nutritional value the remaining part contains. A lower concentration of protein in whey powder, for example, means a higher concentration of carbohydrates and fats. Compensating for this lower concentration of protein with a higher dose results in even more carbohydrates and fats. This must fit into your diet.

Concentration of essential amino acids

As you can see, the concentration of proteins in the powder does not make many plant sources of inferior quality. We mainly assess the quality of the protein itself (and not its concentration in powder) based on the amino acids in that protein. After all, muscle growth is the formation of proteins (protein synthesis) in the muscles from available amino acids from food. Proteins are important because of the amino acids they contain. Some amino acids are more important for muscle growth than others. We distinguish, among others, essential amino acids and non-essential amino acids. Essential amino acids are the amino acids that our bodies cannot produce themselves and must be obtained from food. In this context, the researchers from Maastricht refer to studies indicating that of the amino acids, especially the essential ones are important for stimulating protein synthesis after a meal [2,3]. Until a plateau is reached, research from 2005 suggests a relationship between the amount of ingested essential amino acids and this muscle growth after a meal [4]. Below you can see the concentration of essential amino acids in the tested powders with proteins from different sources. The above chart already makes it clearer why animal proteins are often preferred when it comes to maintaining and growing muscles. The dotted line represents the percentage of essential amino acids that your daily protein intake should contain according to the World Health Organization. All animal proteins are well above this, but this only applies to half of the tested plant proteins.

BCAA’s in plant protein vs. animal protein

But even within those essential amino acids, you can identify specific amino acids that play an important role in muscle growth. Like the BCAAs; leucine, isoleucine, and valine. We can see above that of the plant proteins, only potato protein contains all BCAAs in the recommended amount. Once again, it applies that all animal proteins meet the recommended amounts for all three BCAAs. However, it is also noticeable that the proteins from corn actually contain the highest concentration of leucine of all proteins, including animal ones. Ironically, leucine is often mentioned as the most important amino acid. In the black bar, you can see that in human muscle mass, leucine occurs in the highest concentration of the three BCAAs. Looking at the other essential amino acids (shown right) a similar picture emerges. All animal proteins contain all separate essential amino acids in sufficient amounts, with a few exceptions (whey scoring low in phenylalanine).

Combining proteins

Although there are plant proteins that contain enough essential amino acids, there is only one that contains all individual essential amino acids. In other cases, we see that there can be significant shortages of specific essential amino acids.

About that one exception, potato protein, I will write a separate article soon. The researchers from Maastricht point out that there has not yet been any research showing that, for example, 25 grams of potato protein leads to the same muscle growth as the results shown with 25 grams of whey. My article will address why these studies have not yet been conducted and why we do not see potato protein on every shelf with plant-based proteins.

Combining Plant Proteins

This does not mean that other plant proteins are not suitable for muscle growth. You can mix different sources to ensure sufficient intake of individual essential amino acids. This is what the researchers recommend. But even then, you’re not achieving a comparable favorable amino acid profile as with animal proteins. For example, with proteins from peas, you get all essential amino acids except for methionine, valine, and isoleucine. Suppose you combine this with proteins from brown rice, which contains a lot of methionine, you could compensate for that deficiency easily. However, the problem is that all plant sources, again with the exception of potato, contain too little valine. Deficiencies in leucine also occur frequently. Such combinations mean that you don’t have to increase the dosage of plant proteins relatively as much compared to animal proteins. The methionine deficiency in pea protein is so significant that you would need to consume four times as much protein as from whey, for example. By combining with brown rice protein, this deficiency is almost offset, while deficiencies in valine and isoleucine were already small. This results in a higher dosage of maybe 10 to 20 percent instead of 400 percent. Below you can see how much (actual) protein you need per source to achieve the same amount of leucine (2.7 grams) and essential amino acids (10.9 grams) as in 25 grams of whey. Under ‘amount of raw protein,’ you can see how much powder you need to effectively ingest the amount of protein as mentioned under ‘amount of protein’.

Higher Dosages of Plant Proteins Not Always Sufficient

But even if you theoretically make the right combination, you’re not sure if you achieve the same muscle growth stimulus as with animal proteins. The researchers refer in this context to studies showing that protein synthesis after ingestion of soy and wheat proteins is lower than after ingestion of milk proteins [5-8]. Doubling the dose of soy protein from 20 to 40 grams made no difference in one of these studies [7]. In another study, the effect on protein synthesis was compared between wheat proteins and whey [8]. To achieve the same amount of leucine as in 35 grams of whey, 60 grams of wheat protein was needed. However, this did lead to a significant stimulus for muscle growth.

Combining Plant Proteins with Animal Proteins

To avoid having to eat two to four times as much plant protein as animal protein, you could also combine it with animal proteins. This seems more practical to the researchers from Maastricht. A combination of 50-50 plant/animal proteins would in most cases provide the right amounts of (essential) amino acids with a dosage that is only 5 to 40 percent higher. In theory, this should be sufficient for stimulating protein synthesis. However, in studies, this has so far only been demonstrated with a combination of 75% animal (50% whey, 25% casein) and 25% plant proteins [9-12]. For vegans, such a combination is not an option. But for people like me who want to work on their muscles in a somewhat more responsible way, it could be an option.

Amino Acid Absorption Rate

The amount and type of amino acids, however, are not the only important factors for muscle growth. The degree to which and the speed at which these amino acids are absorbed into the bloodstream also plays a crucial role in contributing to muscle growth. It’s great that the researchers here look at the amount of amino acids in different proteins, but these only have an effect once they also reach the desired location in your body. The speed at which this happens and how long the availability of amino acids remains increased also has consequences for your muscle mass. ‘Muscle growth’ is the net result of protein breakdown in the muscles and the creation of these. In a previous article about fast vs. slow proteins, I discussed research showing that fast whey protein promotes muscle growth mainly by increasing protein synthesis. Slower casein, on the other hand, mainly worked positively by slowing down the breakdown of these proteins.  

Fast vs. Slow Proteins

‘Fast’ and ‘slow’ were determined in that case by specifically looking at the speed at which the leucine in the ingested protein was absorbed into the bloodstream. Whey (triangles) quickly led to a high peak, while casein led to a less high peak but held the increase longer. You can see this in the graph below. So both fast and slow proteins have a positive contribution, albeit in different ways. In practice, athletes often prefer fast proteins after a workout and slow proteins, for example, before sleeping.

Fast Soy

Casein and whey both come from milk and still have a big difference in absorption rate. Even among plant sources, these differences can be significant. You could, therefore, determine the ideal role in muscle growth based on the specific absorption rate of a plant protein. For example, soy is considered a fast protein. However, this did not lead to the same level of protein synthesis as with whey in one study (after exercise and at rest) [15]. The researchers suspected that this was due to the lower amount of leucine in soy. However, there are also studies where no difference was seen in the effect on dry muscle mass between whey and soy. In one study, unfortunately, this was tested with untrained people who received a training program for 6 weeks [16]. These 27 people (18 women and 19 men, 18-37 years old) received 1.2 grams of protein per kilogram of body weight per day. Slightly less than double the recommended minimum of the World Health Organization.

Limited Absorption of Plant Proteins

Fast or slow, you do assume that the amino acids reach the bloodstream and become available for muscle cells. There are studies that have shown that amino acids from plant proteins are absorbed to a lesser extent by the body, such as proteins from soy and wheat. This reduced absorption may partly be explained by the mentioned deficiencies in specific amino acids [13]. This problem should also be able to be limited by the right mix of plant proteins [13]. Other solutions are enrichment of plant proteins with specific amino acids that they naturally possess in smaller quantities. Here, too, further research is needed to confirm the effectiveness of such solutions.

Substances that Limit Absorption of Plant Proteins

Plant (sources of) proteins may also contain substances more often that limit the absorption of proteins. Soybeans, kidney beans, and other legumes may contain many trypsin inhibitors. These are substances that limit the action of trypsin. Trypsin is an enzyme in the small intestine that breaks down proteins from food into smaller chains of amino acids (hydrolysis). Other enzymes then ensure further hydrolysis, allowing the amino acids to be absorbed into the bloodstream. In studies on rats and pigs, such trypsin-suppressing substances were found to reduce amino acid absorption from plant proteins by as much as 50% [14].

Scores for Absorbability of Different Proteins

To somewhat easily assess the degree to which proteins from different sources are absorbed by the body, since 2011, you can use the Digestible Indispensable Amino Acid Score (DIAAS) [17]. Animal proteins generally score higher on this scale than plant proteins concerning good digestibility. Of course, you must distinguish between the raw source and a protein powder. Processing into powder, indeed any processing including cooking, can affect absorbability. Depending on the processing, the mentioned trypsin inhibitors, for example, can be greatly reduced.

Conclusion:

So, are plant proteins less successful in muscle maintenance and growth than animal proteins? Generally: Yes. Unless you carefully evaluate which plant proteins you consume, despite getting enough protein, there is a good chance that ‘def iciencies’ will occur in important amino acids. With animal proteins, this chance is almost absent (‘almost’ due to the small deficiency of whey in phenylalanine). In the Maastricht study, reference was often made to recommended amounts of specific amino acids. This is based on the recommendation of (among others) the World Health Organization. This recommendation is for normal muscle growth and maintenance. Fitness fanatics who want to be above average muscular may have higher needs. In both cases, it is wise to calculate what adjusted dosages are needed if you want to achieve the same as with an equal dose of animal proteins.

References

1. Gorissen SHM, Crombag JJR, Senden JMG, et al. Protein content and amino acid composition of commercially available plant-based protein isolates. Amino Acids. 2018;50(12):1685–1695. doi:10.1007/s00726-018-2640-5
2. Postexercise net protein synthesis in human muscle from orally administered amino acids. Tipton KD, Ferrando AA, Phillips SM, Doyle D Jr, Wolfe RR. Am J Physiol. 1999 Apr; 276(4):E628-34.
3. Essential amino acids are primarily responsible for the amino acid stimulation of muscle protein anabolism in healthy elderly adults. Volpi E, Kobayashi H, Sheffield-Moore M, Mittendorfer B, Wolfe RR. Am J Clin Nutr. 2003 Aug; 78(2):250-8.
4. Anabolic signaling deficits underlie amino acid resistance of wasting, aging muscle. Cuthbertson D, Smith K, Babraj J, Leese G, Waddell T, Atherton P, Wackerhage H, Taylor PM, Rennie MJ FASEB J. 2005 Mar; 19(3):422-4.
5. Ingestion of whey hydrolysate, casein, or soy protein isolate: effects on mixed muscle protein synthesis at rest and following resistance exercise in young men.Tang JE, Moore DR, Kujbida GW, Tarnopolsky MA, Phillips SM. J Appl Physiol (1985). 2009 Sep; 107(3):987-92.
6. Consumption of fluid skim milk promotes greater muscle protein accretion after resistance exercise than does consumption of an isonitrogenous and isoenergetic soy-protein beverage. Wilkinson SB, Tarnopolsky MA, Macdonald MJ, Macdonald JR, Armstrong D, Phillips SM. Am J Clin Nutr. 2007 Apr; 85(4):1031-40.
7. Myofibrillar protein synthesis following ingestion of soy protein isolate at rest and after resistance exercise in elderly men. Yang Y, Churchward-Venne TA, Burd NA, Breen L, Tarnopolsky MA, Phillips SM Nutr Metab (Lond). 2012 Jun 14; 9(1):57.
8. Ingestion of Wheat Protein Increases In Vivo Muscle Protein Synthesis Rates in Healthy Older Men in a Randomized Trial. Gorissen SH, Horstman AM, Franssen R, Crombag JJ, Langer H, Bierau J, Respondek F, van Loon LJ. J Nutr. 2016 Sep; 146(9):1651-9.
9. Reidy PT, Walker DK, Dickinson JM, Gundermann DM, Drummond MJ, Timmerman KL, Fry CS, Borack MS, Cope MB, Mukherjea R, Jennings K, Volpi E, Rasmussen BB. Protein blend ingestion following resistance exercise promotes human muscle protein synthesis. J Nutr. 2013;143(4):410–416. doi: 10.3945/jn.112.168021.
10. Reidy PT, Walker DK, Dickinson JM, Gundermann DM, Drummond MJ, Timmerman KL, Cope MB, Mukherjea R, Jennings K, Volpi E, Rasmussen BB. Soy-dairy protein blend and whey protein ingestion after resistance exercise increases amino acid transport and transporter expression in human skeletal muscle. J Appl Physiol. 2014;116(11):1353–1364. doi: 10.1152/japplphysiol.01093.2013.
11. Reidy PT, Borack MS, Markofski MM, Dickinson JM, Deer RR, Husaini SH, Walker DK, Igbinigie S, Robertson SM, Cope MB, Mukherjea R, Hall-Porter JM, Jennings K, Volpi E, Rasmussen BB. Protein supplementation has minimal effects on muscle adaptations during resistance exercise training in young men: a double-blind randomized clinical trial. J Nutr. 2016;146(9):1660–1669. doi: 10.3945/jn.116.231803.
12. Soy-Dairy Protein Blend or Whey Protein Isolate Ingestion Induces Similar Postexercise Muscle Mechanistic Target of Rapamycin Complex 1 Signaling and Protein Synthesis Responses in Older Men. Borack MS, Reidy PT, Husaini SH, Markofski MM, Deer RR, Richison AB, Lambert BS, Cope MB, Mukherjea R, Jennings K, Volpi E, Rasmussen BB J Nutr. 2016 Dec; 146(12):2468-2475.
13. van Vliet S, Burd NA, van Loon LJ. The Skeletal Muscle Anabolic Response to Plant- versus Animal-Based Protein Consumption. J Nutr. 2015 Sep;145(9):1981-91. doi: 10.3945/jn.114.204305. Epub 2015 Jul 29. Review. PubMed PMID: 26224750
14. Gilani GS, Cockell KA, Sepehr E. Effects of antinutritional factors on protein digestibility and amino acid availability in foods. J AOAC Int. 2005 May-Jun;88(3):967-87. Review. PubMed PMID: 16001874.
15. Tang JE, Moore DR, Kujbida GW, Tarnopolsky MA, Phillips SM. Ingestion of whey hydrolysate, casein, or soy protein isolate: effects on mixed muscle protein synthesis at rest and following resistance exercise in young men. J Appl Physiol (1985). 2009 Sep;107(3):987-92. doi: 10.1152/japplphysiol.00076.2009. Epub 2009 Jul9. PubMed PMID: 19589961.
16. Haun CT, Mobley CB, Vann CG, Romero MA, Roberson PA, Mumford PW, Osburn SC, Holmes HM, Young KC, Moon JR, Roberts MD. Soy protein supplementation is not androgenic or estrogenic in college-aged men when combined with resistance exercise training. Sci Rep. 2018 Feb 16;8(1):11151. doi: 10.1038/s41598-018-29279-6. PMID: 29453317; PMCID: PMC5818906.
17. Wolfe RR. Branched-chain amino acids and muscle protein synthesis in humans: myth or reality? J Int Soc Sports Nutr. 2017;14:30. Published 2017 Aug 22. doi:10.1186/s12970-017-0184-9