Difference between Complete and Incomplete Protein
Proteins are macromolecules made up of amino acids. There are twenty amino acids which are of two types: essential and nonessential amino acids. Out of the twenty amino acids our body can synthesize only eleven amino acids which are known as non-essential amino acids. The other nine amino acids, which our body cannot synthesize, are called essential amino acids.
Each protein molecule is unique in itself as the size, shape, and length of each protein molecule are determined by its specific amino acid sequence and the chemical nature of their side chain (R-group).
Proteins perform a number of important functions in our body like they repair and build tissue, act as enzymes, aid the immune system and act as hormones. Other than water, protein is the most abundant substance in the human body. Protein can be categorized into two types, based on its chemical structure or amino acids: complete proteins and incomplete proteins. By knowing the difference between complete and incomplete proteins you can figure out the right combination of proteins. Let us see how complete protein differs from incomplete protein.
Complete Protein:
A complete protein is a protein which contains all the nine essential amino acids and can be fully utilized by our body to repair and build muscle tissues. Complete proteins are usually found in almost all animal foods like meat, fish, poultry, eggs and dairy products. Quinoa, soybeans and amaranth are some of the plant foods that also contain complete proteins. Whey protein, which is obtained from cow’s milk, is one of the fastest-digesting complete proteins. It quickly delivers nutrients to the body tissues or muscle.
Incomplete Protein:
The incomplete protein is a protein which lacks one or more essential amino acids which means it does not contain all the nine essential amino acids. When consumed, incomplete proteins are not fully utilized by the body. Incomplete proteins are usually found in plant foods as the plant foods contain few, not all the essential amino acids. Common plant foods which provide incomplete proteins include nuts, seeds, green peas, lentils, most grains etc. Foods which contain incomplete proteins when consumed in combination with other such foods can provide you complete protein or all the essential amino acids, e.g. a combination of beans and milk or rice can provide you all the essential amino acids or complete protein. Some other combinations of foods to make incomplete proteins are as follows:
- Corn with beans
- Yogurt with walnuts
- Brown rice with green peas
- Nuts with legumes
- Legumes with seeds
Based on the above information, some of the key differences between complete and incomplete proteins are as follows:
| Complete Protein | Incomplete Protein |
|---|---|
| It contains all the nine essential amino acids. | It lacks one or more essential amino acids or does not contain all the nine essential amino acids. |
| It is mostly found in animal foods. | It is usually found in almost all plant foods. |
| A single animal food can provide all the essential amino acids. | A combination of plant foods can provide complete protein (all essential amino acids). |
| Sources include animal foods like fish, meat, eggs, etc and some plant foods like quinoa and soyabean. | Sources include plant foods like nuts, lentils, green peas etc. |