Proteins comprise amino acids that form long chains together. You can think of a protein as a bead string in which every bead is an amino acid. There are 20 amino acids that help make different proteins. Proteins do most of their cell work and do different jobs. Here are 8 functions of protein in your body.
1. Protein Provides Energy
Proteins can provide energy to your body. Thus, protein contains four calories per gram, the same fuel provided by carbs. Fats give the most energy, at nine calories per gram.
As we commonly use this essential food throughout the body, the last thing the body wants to use for fuel is protein. Carbs and fats are much better suited for energy supply, as your body has reserved for fuel use. In fact, they are more metabolized compared to protein (1).
Protein provides the body under normal circumstances with very little of its energy needs. Your body breaks down the skeletal muscle in a state of fasting so that the amino acids can provide you with energy (2).
Your body also uses broken-down skeletal muscle amino acids if the storage of carbohydrates is low. This can happen after exhaustive exercise, or if you rarely eat enough calories (3).
2. Provides Structure
Some proteins are fibrous, giving stiffness and rigidity to cells and tissues. Such proteins include keratin, collagen, and elastin, which help to shape the connective tissue within your body of certain structures (4).
Keratin is a protein found in your skin, hair, and nails. Collagen is your body’s most abundant protein and is your bones, tendons, ligaments, and skin’s structural protein (5).
Elastin is more flexible than collagen several hundred times. Upon stretching or contracting, most tissues in your body will return to their original forms, such as your uterus, lungs, and arteries.
3. Boosts Immune Health
Proteins help to prevent infection by forming immunoglobulins or antibodies. Antibodies are blood proteins that help protect the body from dangerous invaders such as bacteria and viruses (7).
Your body produces antibodies that tag them for elimination when these invaders enter your cells. Bacteria and viruses would be free to multiply and overwhelm your body with the disease that they cause without these antibodies (8).
Once your body produces antibodies to a specific bacterium or virus, your cells will never forget how to make them. This enables the antibodies to respond if the body is invaded by a specific disease agent. As a result, the body develops immunity to the diseases it is exposed to (9, 10).
4. Muscle Growth and Maintenance
Your body needs protein for tissue growth and maintenance. Yet the proteins of your body are in constant turnover. The body breaks down the same amount of protein it uses to build and rebuild tissues in normal circumstances.
It breaks down more protein many times than it can produce, thus increasing the needs of your body. It occurs during illness, pregnancy and breastfeeding cycles (11).
Keep in mind: Older adults and athletes also need more protein to recover from injury (12).
5. Proper pH Levels
Protein plays a vital role in controlling blood and other body fluid levels. The pH scale is used to measure the balance between acids (13).
It is between 0 and 14, with 0 being the most acidic, 7 neutral, and 14 being the most alkaline. Several buffering systems can preserve normal pH levels for your body fluids. A constant pH is required because even a slight pH change can be harmful or deadly (15).
Proteins are one way the body controls pH. Hemoglobin, a protein that shapes red blood cells, is an example.
Hemoglobin binds small amounts of acid to help maintain the blood’s usual pH level. Phosphate and bicarbonate are the other buffer structures in your skin (16).
6. Transports Nutrients
Proteins convey substances in the bloodstream into cells. Nutrients such as vitamins or minerals, blood sugar, cholesterol, and oxygen are the substances transported by these proteins (17).
Hemoglobin, for example, is a protein that carries oxygen to body tissues from your lungs. Glucose transporters (GLUT), while lipoproteins carry cholesterol and other fats in your blood, transfer glucose to your cells.
Protein carriers are unique, so they only bind to particular substances. In other words, a protein that carries glucose will not carry cholesterol (18).
Proteins also have functions in the processing. Ferritin is an iron-storing protein. Another protein that is processed is casein, which is the key milk protein that helps babies grow (19).
7. Balances Fluids
Proteins control the functions of the body to maintain fluid balance. Albumin and globulin are blood proteins that help keep the fluid balance of your body by attracting and keeping the liquid (20).
If you don’t consume enough protein, your albumin and globulin levels will eventually fall. As a result, these proteins can no longer hold blood in your blood vessels and the liquid is pushed into the gaps between your cells.
As the fluid keeps building up in the spaces between your cells, swelling or edema occurs, in the stomach’s region.
Kwashiorkor is rare in the world’s developed regions and occurs more in areas of poverty.
8. Biochemical Reactions
Enzymes are proteins that support thousands of biochemical reactions occurring inside and outside the cells (23).
The enzyme structure allows them to interact inside the cell with other molecules called substrates, catalyzing reactions important to your metabolism (24).
However, enzymes may function outside the cell, such as digestive enzymes such as lactase and sucrase, which help digest sugar. Many enzymes require other molecules for a reaction, such as vitamins or minerals. Lack of or insufficient function of these enzymes may lead to disease (25).
The Bottom Line
Protein has a lot of body functions. This helps to fix and build the tissues of your body, enables metabolic reactions to occur and regulates body functions. Proteins also maintain proper pH and fluid balance besides providing a structural foundation for your body. They keep your immune system healthy, carry and store nutrients and they can serve as an energy source. Both functions make protein one of the most important health nutrients.
- 22 Delicious High-Protein Foods You Should Eat
- 10 Proven Whey Protein Health Benefits Based On Science