The topic of protein is always in the spotlight and attracts more attention from consumers. Nowadays, when we enter a supermarket, we are overwhelmed with information such as “PROTEIN”, “HIGH IN PROTEIN”, “25g PROTEIN”, among others. It is clear that brands are increasingly looking to introduce protein-rich products to the market, such as yogurts, cheeses, milk, cookies, cereals and even bread. But when we have so much on offer, more questions also arise, such as “Is it worth the price?”, “But should I opt for proteins of animal or vegetable origin?”, “Is whey protein the best? Or will a vegetable protein do the job well?”, among other questions. The question that we will address in our article is precisely which protein, animal or vegetable, has a more efficient effect on muscle protein synthesis (MPS).
But what are the differences between them?
The main differences between animal proteins and plant proteins are in the amino acid composition, digestibility and impact on muscle protein synthesis (MPS):
Proteins of animal origin (meat, eggs, dairy products, fish)
· Contain all essential amino acids (complete proteins);
· Higher leucine content, essential for MPS;
· Better digestibility and absorption by the body.
Proteins of plant origin (legumes, cereals, oilseeds)
· Some are deficient in certain essential amino acids (except soy, quinoa and amaranth);
· Lower leucine content compared to animal proteins;
· Slightly lower digestibility.
But then is animal protein worse?
Plant-based protein is often considered inferior to animal protein due to its amino acid profile and digestibility. However, this does not mean that it is any less effective for muscle protein synthesis.
The main difference between the two is that some sources of plant-based protein are deficient in certain essential amino acids. However, this can be easily resolved by combining different sources of plant-based protein, ensuring a complete amino acid profile. A classic example is the combination of rice and peas: rice is low in lysine but high in methionine, while peas are high in lysine and low in methionine. Together, these proteins complement each other and provide all the essential amino acids needed by the body. Furthermore, studies suggest that when the total intake of plant-based protein is slightly increased, the differences compared to animal protein disappear. In other words, by consuming a slightly larger amount of plant-based protein, the body is able to compensate for possible differences in the digestibility and quality of amino acids.
But is it the same for all ages?
It seems that for most ages, as long as there is compensation from vegetable protein, muscle protein synthesis is quite efficient. However, another study suggests that from the age of 65, animal protein should be prioritized.
Conclusion
In short, plant-based proteins can be just as effective as animal-based proteins when combined correctly and consumed in adequate amounts. For younger people, the source of protein is less important, but after the age of 65, prioritizing animal-based proteins can be beneficial for maintaining lean mass.
Rui Lopes
BMS Nutritionists
References
Messina, Mark, et al. “No Difference between the Effects of Supplementing with Soy Protein versus Animal Protein on Gains in Muscle Mass and Strength in Response to Resistance Exercise.” International Journal of Sport Nutrition and Exercise Metabolism , vol. 28, no. 6, 1 Nov. 2018, pp. 674–685, www.ncbi.nlm.nih.gov/pubmed/29722584, https://doi.org/10.1123/ijsnem.2018-0071 .
“Effects of Plant- versus Animal-Based Proteins on Muscle Protein Synthesis: A Systematic Review with Meta-Analysis | SportRxiv.” Sportrxiv.org , 2020, sportrxiv.org/index.php/server/preprint/view/526/version/676. Accessed 3 Mar. 2025.
Messina, Mark, et al. “No Difference between the Effects of Supplementing with Soy Protein versus Animal Protein on Gains in Muscle Mass and Strength in Response to Resistance Exercise.” International Journal of Sport Nutrition and Exercise Metabolism , vol. 28, no. 6, 1 Nov. 2018, pp. 674–685, www.ncbi.nlm.nih.gov/pubmed/29722584, https://doi.org/10.1123/ijsnem.2018-0071.