In a new study from the University of São Paulo, researchers found that protein intake is more important than protein source if the goal is to gain muscle strength and mass.
They compared the effects of strength training in people with a vegan or omnivorous diet, both with protein content considered adequate.
Protein sources are characterized primarily on the basis of essential amino acids, especially leukin, which plays a key role in anabolic stimulation of skeletal muscles.
Animal protein has more leukin than plant protein. Leukin is an essential amino acid in the anabolic stimulus signaling process.
A plant-based diet is often thought to contain less leukin and hence trigger less anabolic stimulation, potentially affecting vegans’ capacity for muscle mass gain.
In the study, the team tested 38 healthy young adults, half of whom were vegans and half omnivores.
In addition to performing exercises to increase muscle strength and mass, the volunteers followed either a mixed diet with both animal and plant protein, or an entirely plant-based diet, both with the recommended protein content (1.6 gram of protein per kilogram of body weight per day).
At the end of three months, the team found there was no difference between vegans and omnivores in terms of muscle strength and mass increase.
The findings showed that there is no impairment of muscle mass gain for young adult vegans if they ingest the right amount of protein.
However, the researchers stress that for the purposes of experimental control, protein intake was made the same in both diets by means of protein supplements.
Omnivores and vegans were given milk serum protein isolate or soy protein respectively in accordance with individual dietary needs in order to attain the targeted protein intake.
The team says foods of animal origin generally have a higher protein content. Meat, milk and eggs contain more protein per gram than rice and beans, for example.
In daily meals, vegans would need to ingest a large amount of food to obtain the same amount of protein. In some specific cases, this could be a major challenge.
The study is published in Sports Medicine. One author of the study is Hamilton Roschel.