The key difference between complete and incomplete proteins is that complete proteins contain sufficient amounts of all nine essential amino acids while incomplete proteins lack one or more of nine essential amino acids.
Proteins are macromolecules that perform many important functions in our body. As they are highly diverse, these proteins carry out many different functions in our body, including enzyme catalysis, defensive, transport, supportive, motion, and regulatory functions. Twenty different amino acids act as the building blocks to make huge protein molecules. Generally, amino acid sequences and the chemical nature of their side chain (R- group) determine the primary structure, size, shape, and the length of each protein molecule; hence, each protein is unique in our body.
The amino acids that occur in the proteins can be categorized into two: essential and non-essential amino acids. Non-essential amino acids can be produced in the body itself while essential amino acids must be obtained via foods as they cannot be produced by the body itself. It is essential to take protein-rich food in order to obtain all the essential amino acids required to maintain the most important functions of the body. The terms ‘complete’ and ‘incomplete’ mainly categorize protein sources based on the type of amino acids present within them.
CONTENTS
1. Overview and Key Difference
2. What are Complete Proteins
3. What are Incomplete Proteins
4. Similarities Between Complete and Incomplete Proteins
5. Side by Side Comparison – Complete vs Incomplete Proteins in Tabular Form
6. Summary
What are Complete Proteins?
Complete proteins are the proteins that contain sufficient quantities of all nine essential amino acids. Some food contains proteins with all the essential amino acids required for the body. Usually, animal sources of proteins contain complete proteins. Therefore, protein sources such as fish, meat, poultry, dairy products, and eggs contain complete proteins.
Figure 01: Fish is a Source of Complete Protein
In addition, plant products such as soybeans and quinoa contain complete proteins. Therefore, vegetarians can consume these plant products daily in order to fulfil their protein requirement.
What are Incomplete Proteins?
Incomplete proteins are the proteins that lack one or more essential amino acids. Most plant products contain incomplete proteins. Thus, cereal grains and legume-like plant products contain incomplete proteins.
Figure 02: Legumes are a Source of Incomplete Proteins
Foods with the incomplete protein, when eaten in combination, for example, milk and beans, can provide all the essential amino acids required for the body. Therefore, we should consume more than one source of incomplete proteins in order to fulfil our protein requirement.
What are the Similarities Between Complete and Incomplete Proteins?
- Complete and incomplete proteins are the two main types of proteins.
- Both contain essential amino acids and are made up of amino acids
- Moreover, they are important nutrients for the proper functioning of our body.
- Plant products contain both complete and incomplete proteins.
What is the Difference Between Complete and Incomplete Proteins?
Complete and incomplete proteins are two types of proteins. Complete proteins contain all essential amino acids, while incomplete proteins lack one or more essential amino acids. Thus, this is the key difference between complete and incomplete proteins. Due to their composition, one type of complete protein source is sufficient to provide a person’s protein requirement, but more than one incomplete protein source or a combination of incomplete protein sources are required to provide the protein requirement of a person. So, we can consider this as another difference between complete and incomplete proteins.
Besides, most animal products contain complete proteins, while most plant products contain incomplete proteins.
Summary – Complete vs Incomplete Proteins
Proteins are made by twenty standard amino acids. Among them, eleven are non-essential amino acids, while nine are essential amino acids. Based on the presence and absence of essential amino acids in a protein, there are two types of proteins as complete and incomplete. Complete proteins contain all the essential amino acids, while incomplete proteins lack one or more essential amino acids. Thus, this is the key difference between complete and incomplete proteins.
Reference:
1. “Complete Protein.” Wikipedia, Wikimedia Foundation, 22 Apr. 2019, Available here.
2. “Incomplete Proteins.” Healthy Eating, Available here.
Image Courtesy:
1. “3754425” (CC0) via Pxhere
2. “Legumes-665788” By 821292 – archive copy at the Wayback Machine (archived on 8 April 2016) (CC0) via Commons Wikimedia
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