Protein is a macronutrient. It is one of the three nutrients found in food that the body needs in large amounts. It is essential for the maintenance and building of body tissues and muscle.
The Benefits of Protein
High-protein, low-carbohydrate diets are the hottest thing since sliced flank steak and every food marketer in the known universe appears to want a piece of the protein pie.
Body builders are snatching, grabbing, and gulping down protein shakes. Dieters are gobbling down protein bars (and shunning pasta) in hopes of quick weight loss.
It's easy to understand the excitement. Protein is an important component of every cell in the body. Hair and nails are mostly made of protein. Your body uses protein to build and repair tissues. You also use protein to make enzymes, hormones, and other body chemicals. Protein is an important building block of bones, muscles, cartilage, skin, and blood.
The truth is, we need less total protein that you might think. But we could all benefit from getting more protein from better food sources.
We've all heard the myth that extra protein builds more muscle. In fact, the only way to build muscle is through exercise. Bodies need a modest amount of protein to function well. Extra protein doesn't give you extra strength. According to the U.S. Department of Health and Human Services:
Protein is crucial to good health. In fact, the name comes from the Greek word protease, meaning “primary” or “first place.” Proteins are made up of amino acids that join together to form long chains. You can think of a protein as a string of beads in which each bead is an amino acid. There are 20 amino acids that help form the thousands of different proteins in your body. Proteins do most of their work in the cell and perform various jobs.
Here are 9 important functions of protein in your body.
Your body needs protein for growth and maintenance of tissues. Yet, your body’s proteins are in a constant state of turnover.
Under normal circumstances, your body breaks down the same amount of protein that it uses to build and repair tissues. Other times, it breaks down more protein than it can create, thus increasing your body’s needs.
Enzymes are proteins that aid the thousands of biochemical reactions that take place within and outside of your cells. The structure of enzymes allows them to combine with other molecules inside the cell called substrates, which catalyze reactions that are essential to your metabolism. Enzymes may also function outside the cell, such as digestive enzymes like lactase and sucrose, which help digest sugar. Some enzymes require other molecules, such as vitamins or minerals, for a reaction to take place.
Bodily functions that depend on enzymes include:
Lack or improper function of these enzymes can result in disease.
Some proteins are hormones, which are chemical messengers that aid communication between your cells, tissues and organs. They’re made and secreted by endocrine tissues or glands and then transported in your blood to their target tissues or organs where they bind to protein receptors on the cell surface.
Hormones can be grouped into three main categories:
Protein and polypeptides make up most of your body’s hormones.
Some examples include:
Some proteins are fibrous and provide cells and tissues with stiffness and rigidity. These proteins include keratin, collagen and elastic, which help form the connective framework of certain structures in your body.
Protein plays a vital role in regulating the concentrations of acids and bases in your blood and other bodily fluids.
The balance between acids and bases is measured using the pH scale. It ranges from 0 to 14, with 0 being the most acidic, 7 neutral and 14 the most alkaline.
Proteins regulate body processes to maintain fluid balance. Albumin and globulin are proteins in your blood that help maintain your body’s fluid balance by attracting and retaining water.
If you don’t eat enough protein, your levels of albumin and globulin eventually decrease.
As the fluid continues to build up in the spaces between your cells, swelling or edema occurs, particularly in the stomach region.
This is a form of severe protein malnutrition called kwashiorkor that develops when a person is consuming enough calories but does not consume enough protein. Kwashiorkor is rare in developed regions of the world and occurs more often in areas of starvation.
Proteins help form immunoglobulins, or antibodies, to fight infection. Antibodies are proteins in your blood that help protect your body from harmful invaders like bacteria and viruses.
When these foreign invaders enter your cells, your body produces antibodies that tag them for elimination.
Without these antibodies, bacteria and viruses would be free to multiply and overwhelm your body with the disease they cause.
Transport proteins carry substances throughout your bloodstream into cells, out of cells or within cells. The substances transported by these proteins include nutrients like vitamins or minerals, blood sugar, cholesterol and oxygen.
For example, hemoglobin is a protein that carries oxygen from your lungs to body tissues. Glucose transporters (GLUT) move glucose to your cells, while lipoproteins transport cholesterol and other fats in your blood.
Proteins can supply your body with energy. Protein contains four calories per gram, the same amount of energy that carbs provide. Fats supply the most energy, at nine calories per gram.
However, the last thing your body wants to use for energy is protein since this valuable nutrient is widely used throughout your body.
Protein has many roles in your body. It helps repair and build your body’s tissues, allows metabolic reactions to take place and coordinates bodily functions. In addition to providing your body with a structural framework, proteins also maintain proper pH and fluid balance. Finally, they keep your immune system strong, transport and store nutrients and can act as an energy source, if needed. Collectively, these functions make protein one of the most important nutrients for your health.