Amino Acids

We have all heard of proteins as it is a macronutrient that our body needs.  However, did you know that there are two kinds of proteins - nonessential and essential?  The good news is that the body can create more than half of the amino acids for itself as long as it is given enough nitrogen to form the amino group and fragments from carbohydrate and fat that assembles the rest of the structure.  The protein you eat in food typically provides those needed amino acids. These amino acids are considered nonessential.

On the other hand, there are 9 amino acids your body cannot make at all, or cannot make in sufficient quantity.  That means, we must consume these amino acids by our food.  To prevent protein breakdown we need to ensure that our diet supplies at least these 9 essential amino acids, plus the necessary nitrogen-containing amino acid groups and energy.  Unfortunately, the body does not store extra amino acids, so that means an excess in either is wasted or they are used for another purpose. 

Foods that are considered to be a complete protein contain all of the essential amino acids we require.  Animal proteins from meat, fish, poultry, cheese, eggs, and milk usually are complete.  The only exception would be gelatin as it is missing tryptophan, so it cannot help with growth if it is used as the only protein.  Some plant protein from vegetables, grains, and legumes tend to be limited in one or more essential amino acid.  Soy protein however is considered a complete protein.  With that in mind, plant proteins supply less protein per unit than animal protein.  That is why vegetarians need to combine complimentary plant-protein foods.  Doing so helps them to obtain the essential amino acids they need. Examples of this food combining are black beans and rice, peanut butter on whole grain bread, or tofu with stir fried vegetables with brown rice.