Amino acids – building blocks of protein – are needed for growth, tissue repair, and hormone production and can also be used as an indirect source of energy. There are nine amino acids that are considered essential, meaning the body cannot make them, so they must be ingested through foods. Animal proteins contain all nine essential amino acids in sufficient amounts and are considered ‘complete’ proteins, while plant-based proteins may contain lower amounts of one or more essential amino acids.
Historically, it was believed that plant proteins needed to be combined to make up a complete amino acid profile, which was known as “complementary proteins.” However, we now know that the body is able to obtain all essential amino acids from plant-based foods and people can meet their protein needs as long as calorie consumption and total protein intake are adequate. It is also recommended that plant-based eaters consume a variety of plant protein sources.