Q: When eating vegetarian meals, is it important to choose food combinations that provide complementary protein?
A: You are referring to the fact that most plant foods have incomplete protein, meaning they are low in one or more of the essential amino acids that we need to form muscle and other body tissues, enzymes, hormones and more. Amino acids are the building blocks that make up protein. For example, rice and beans each supply amino acids that are low in the other. In the past, it was thought that these needed to be eaten at the same meal for the body to use the amino acids. Now studies show that the body can get needed amino acids from protein eaten throughout the same day.
Different types of plant foods vary in amino acid content. That’s why it is important, especially if you are eating primarily vegetarian meals, to get a variety of protein sources. For example, grains, nuts and vegetables might not be able to meet needs for the amino acid called lysine without the help of legumes (dried beans and peas). If you eat a variety of whole grains, legumes (dried beans and peas), seeds, nuts and vegetables throughout the day, and in amounts that meet your calorie needs, you should meet protein and amino acid needs without focusing on creating specific combinations in each meal.
Karen Collins, MS, RDN, CDN, FAND
American Institute for Cancer Research