Plant proteins generally contain lower levels of leucine10 compared to animal proteins. “For example,” says Layman, “grains such as wheat and quinoa contain less than 7% leucine, and legumes such as soy or pea contain about 8% leucine.” Chicken breast, on the other hand, is about 12% leucine.
However, with careful dietary planning, vegetarians and vegans can obtain sufficient leucine to support muscle growth and overall health.
Since plant proteins may not provide optimal amounts of leucine individually, plant-based eaters can ensure adequate leucine intake by combining different plant protein sources11. For example, eating legumes, grains, nuts, and seeds can create complete protein profiles that offer all the essential amino acids, including leucine.
In addition, prioritizing leucine-rich plant-based foods like tofu, tempeh, edamame, pumpkin seeds, and certain legumes can further boost your leucine intake.
“For vegetarians, it’s straightforward to get enough leucine by consuming dairy and eggs,” says Church. “Vegans need to consider complementary protein sources such as corn, soy, and rice. However, modern commercially available protein isolates and essential amino acid supplements (generally from vegan sources) tend to be high in leucine content.”