Amino acids are the building blocks that make proteins. All vegetables and grains contain all eight of the essential amino acids (as well as the twelve other non-essential). While some vegetables have higher or lower proportion of certain amino acids than others, when eaten in amounts to satisfy your caloric needs, a sufficient amount of all essential amino acids is provided. Today’s nutritional science has deemphasized the importance of protein because we now know that it is easy to get enough, and that too much is not good.
Scientific studies on human protein requirements demonstrate that adults require 20-35 grams of protein per day.1 Today, the average American consumes 100-120 grams of protein per day, mostly in the form of animal products. This high level of animal product consumption has been linked to not just heart disease and strokes, but to higher rates of cancer, as well.2 We simply don’t need all this protein. Even people who eat a total vegetarian (vegan) diet, which contains no animal products, have been found to consume 60-80 grams of protein per day, well above the minimum requirement.3
1. Rose W. “The amino acid requirements of adult man.” Nutritional Abstracts and Reviews 1957;27:631.
2. Kelemen LE; Kushi LH; Jacobs DR; Cerhan JR. “Associations of dietary protein with disease and mortality in a prospective study of postmenopausal women.” Am J Epidemiol 2005;161(3):239-49.
Kant AK; Schatzkin A; Graubard BI; Schairer C. “A prospective study of diet quality and mortality in women.” JAMA 2000;283(16):2109-15.
Meydani M. “Nutrition interventions in aging and age-associated disease.” Ann NY Acad Sci 2001;923:226-35.
3. Hardage M. “Nutritional studies of vegetarians.” Journal of the American Dietetic Association 1966;48:25.