When I have vegetarians or vegans come see me, most are concerned that they might not be meeting their overall macro- and micronutrient needs not only for general health, but for athletic performance as well. When assessing their intake, one topic we often discuss is complete protein combinations at meals and snacks. But what are complete proteins and why does it matter?
What are complete protein combinations (the science)?
Protein is made up of amino acids (you probably learned that these are the "building blocks" of protein in high school). There are 9 essential amino acids. An amino acid is essential if the body does not make it on its own, meaning you must consume food that contains these 9 amino acids. Most animal proteins naturally contain all 9 essential amino acids in enough amounts that they can stand alone as good quality protein options for meals and snacks. However, many plant sources of protein have what is called a "limiting" amino acid, or an amino acid that is in a relatively low amount. The idea behind consuming complete protein combinations means combining foods that together provide an adequate amount of all 9 essential amino acids. So together they "complement" eachother's limiting amino acid, bringing the total between the two foods to an adequate amount for all 9 essential amino acids.
What is the problem with not consuming complete protein combinations?
Consuming foods that do not contain all 9 essential amino acids in adequate amounts limits how well your body digests and utilizes the protein in that food. So, in order to get the most "bang for your buck", it is best to combine foods to assure your body can most efficiently utilize what you are eating.
What are examples of complete protein combinations?
Some examples include (note not all appropriate for vegans):
-Grains and legumes: rice and beans, peanut butter sandwich, tortillas with beans
-Grains or vegetables with dairy or soy: pasta with cheese, baked potato with dairy/soy sour cream, rice pudding, cereal with milk
-Legumes and nuts: Hummus made with chickpeas and tahini
-Soy protein: Tofu smoothie, tofu stir-fry, vegetarian burgers
How big of a problem is this for vegetarians or vegans?
Luckily many combinations (as you might have noticed) are ones that are typically eaten in our culture. However, the more restrictive a diet, the more opportunity for this to be a problem. Often I find that it is not a matter of getting the foods in, but making sure the foods are eating in the correct combinations. I recommend you review the list above and make an effort to create complementary protein combinations at every meal.