The Myth of Complementary Proteins
Although not as frequently asked as “where do you get your protein,” one question, or rather a myth that vegans encounter on a regular basis is that you have to combine foods to get all of your amino acids and complete proteins.
Although this is completely untrue, there are a few caveats and important details to note depending on age, as you’ll see below.
Why Vegans Do Not Need To Combine Amino Acids
So, what are amino acids, and why are they important?
Although new scientific studies indicate that hundreds exist, only 20 amino acids are active in the human body and are considered to be the “building blocks” of protein. Some are essential – meaning that your body absolutely needs them and can only obtain these forms of amino acids from a dietary source. Others are non-essential – meaning that your body has the ability to generate them on its own.
The essential amino acids are histidine, isoleucine, leucine, lysine, methionine which transforms into cystine, phenylalanine which transforms into tyrosine, threonine, tryptophan, and valine.
For many years, scientists and doctors believed that vegans had to combine certain foods to maintain optimal health and get all of the essential amino acids from their diet. This became known as the theory of “complementary proteins.” This idea was due, in large part, to the famous book written by researcher Francis Moore Lappe, Diet for a Small Planet.Combining amino acids to form complete proteins is not necessary in a vegan dietClick To Tweet
As noted in Lappe’s original publication and according to others, some foods, such as whole grains and legumes, contain low levels of lysine and methionine, respectively, while other plant foods offer limited amounts of other types of amino acids. Thus, the idea of complementary proteins was that you could, for example, consume a meal of rice and beans, to meet all of your daily amino acid requirements.
However, this theory regarding complementary proteins was debunked in recent years due to emerging science and a better understanding of how our bodies function and store nutrients. It is now widely accepted and common knowledge that our bodies store amino acids in the liver, which are then released on a regular basis, as needed. This biological process allows these protein building blocks to combine and complement each other throughout the day and with each subsequent meal.
Special Amino Acid Considerations For Vegans
While all plant foods contain all eight of the essential amino acids that vegan adults require for good health and to build and maintain muscle mass (yes, even vegetables), the amount varies from food to food. It’s also vital to note that children require the ninth essential amino acid which is not crucial for adults, histidine. Therefore, offering meals rich in specific protein sources is critically important in raising a vegan child. Foods such as quinoa, soy, hemp, pumpkin seeds, buckwheat, chia, and supplements such as spirulina, contain all nine essential amino acids as well as many of the non-essential amino acids. And some, such as soy and quinoa are more balanced in content and abundant in the nine essential amino acids, and are therefore considered to be “complete proteins.”
As you can see, vegans of all ages and activity levels can obtain the necessary essential and non-essential amino acids by consuming an adequate supply of calories and including a variety of plant-based foods in their daily menu. Limiting processed foods is also prudent, as these convenience foods may reduce your intake of a variety of amino acids as well as other vital nutrients that can only be found in whole, fresh foods.
- Marsh, Kate A., Elizabeth A. Munn, and Surinder K. Baines. “Protein and vegetarian diets.” The Medical Journal of Australia 1, no. 2 (June 04, 2012): 7-10. doi:10.5694/mjao11.11492.
- “Vegetarian Diets.” American Heart Association. Accessed February 17, 2017. https://www.heart.org/HEARTORG/HealthyLiving/HealthyEating/Vegetarian-Diets_UCM_306032_Article.jsp?appName=MobileApp.
- Craig, W. J., and A. R. Mangels. “Position of the American Dietetic Association: Vegetarian Diets.” Journal of the American Dietetic Association 109, no. 7 (July 2009): 1266-282. doi:10.1016/j.jada.2009.05.027.
- Amit, M. “Vegetarian diets in children and adolescents.” Paediatrics & Child Health. May & June 2010. Accessed February 17, 2017. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2912628/.