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The Ultimate Guide to Proteins Part 1: Functions

We often discuss the link between protein and muscle growth. However, apart from protein’s influence on building muscles, do you know that its other functions to our body? In this ultimate guide to proteins, part one of our series, we’ll give you a little bit of the essentials you need to know.

Quick Trip to its Composition

Proteins are composed of amino acids that contain oxygen, hydrogen, carbon, and nitrogen. Its nitrogen component makes it different from alcohol, carbohydrates, and fats. These amino acids are the building blocks of our muscles. In that case, it is well-known for its role in the development and growth of tissues, including muscle fibers among others.

What Protein is Most Known For

Protein played a vital role in athlete’s diet way back the ancient Olympiads. As discussed earlier, protein is responsible for the development and growth of tissue, including muscle tissue. It is a primary function of protein. But, it can only function best when energy intake from fat and carbohydrate is sufficient.

Because of so much emphasis to protein’s primary function, it is easy to neglect that protein can also be the basis of enzymes and many hormones.

Although, protein is primary known for development and growth of tissue, its building blocks, the amino acids, can be used to provide energy. Amino acids are important source of energy even though carbohydrates and fats are the main suppliers of energy for a prolonged endurance exercise as example.

Once we eat protein-rich food, proteins are broken down into amino acids through the processes of digestion and absorption. After digestion and absorption, amino acids are transported to the liver, wherein the amino acids are being metabolized.

Your body consists of proteins that are constantly being manufactured and broken down. The degraded body proteins together with dietary protein provide a stable stream of amino acids for protein synthesis. For a prolonged starvation state as an example, your body has to maintain nitrogen balance even though it is being compromised and muscle tissue will be sacrificed to secure survival.

Protein Consumption: A Glimpse

Proteins are present in both plant and animal meat. Yet, these two give a different quality of protein, the amount and type of amino acids among others. For example, industrialized countries have easy access and can consume an adequate amount of protein with ample quality.

The recommended consumption of protein for athletes is relatively higher than for those who are not. However, this protein consumption exceeds proposition in both athletes and non-athletes when the energy (kcal) intake is enough. There is a right time to protein intake, especially in the recovery or post-exercise period. Athletes make sure to have numerous protein-containing foods and have to take protein supplements. These protein supplements are generally manufactured using milk or soy, which is known as food proteins. But, these protein supplements have not been proven more effective than those of protein-containing foods.

Functions of Protein

Maintenance and Growth

More than anything else, your body has to take protein for the growth and maintenance of tissues. Yet, the proteins in your body are in a constant state of turnover. Normally, your body is breaking down the same amount of protein as to building and repairing tissues.

Other times, it breaks down more protein than it can create, hence increasing your body’s needs. These circumstances typically happen in time of illness, during pregnancy, while breastfeeding, and people recovering from an injury or surgery. Older adults and athletes need more protein intake as well.

Causes Biochemical Reactions

Thousands of biochemical reactions are taking place within and outside of your cells. With this, enzymes are proteins that aid these reactions.

This enzymes makeup allows them to integrate with other molecules within the cell called substrates. Substrates catalyze these reactions that are essential to your metabolism. Aside from this inner activity, enzymes can also function outside the cell.

The digestive enzymes such as lactase and sucrase help to digest sugar. However, some enzymes require other molecules, such as minerals or vitamins, for a reaction to take place. There are bodily functions that greatly depend on enzymes. These are digestion, blood clotting, energy production, and muscle contraction. If these enzymes function improperly, it could result in disease.

Acts as Chemical Messengers

Proteins are not just limited to muscle building and enzymes. Some of it are hormones, which serve as chemical messengers that assist communication between your cells, tissues, and organs.

These hormones are made and secreted by endocrine tissues or glands that eventually transported in your blood to their designated tissues or organs where they fasten to protein receptors on the cell surface.

Hormones can be grouped into three main categories:

  • Protein and peptides – hormones that are made from chains of amino acids. It ranges from a few to several hundred.
  • Amines – hormones that are made from the individual amino acids tryptophan or tyrosine. These hormones are related to sleep and metabolism.
  • Steroids – are made from the fat cholesterol. There are hormones that are steroid-based such as sex hormones, testosterone, and estrogen.

Provides Strength, Elasticity, and Structure

Some proteins can also be fibrous and provide cells and tissues with stiffness. These proteins include collagen, elastin, and keratin. They help form the connective framework of particular structures in your body.

Keratin is a structural protein that is present in your skin, nails, and hair. Collagen has the most sufficient amount of protein in your body. It makes your bones, tendons, ligaments, and skin.

Meanwhile, elastin is way more flexible than collagen. It is very elastic that enables many tissues in your body to return to their original shape after contracting or stretching, like uterus, lungs, and arteries.

Maintains Proper pH

Protein Digestion Enyzmes

Protein is also responsible for regulating the concentrations of acids and bases in your blood and some bodily fluids.

pH scale measures the balance between acids and bases. The measurement ranges from 0 through 14, wherein 0 being the most acidic, 7 is for neutral, and 14 the most alkaline.

A constant pH is essential. Even a minimal change in measurement can be harmful or deadly. But, there are variety of buffering systems that allow your bodily fluids to retain normal pH ranges. Proteins regulate your body’s pH. Example of buffer system is the hemoglobin, a protein that makes up red blood cells. Other buffer systems present in your body are phosphate and bicarbonate.

Maintains Fluid Balance Between Blood and Surrounding Tissues

Proteins in your blood, also known as albumin and globulin, attract and retain water which helps maintain your body’s fluid balance. Levels of both globulin and albumin eventually decrease with insufficient protein consumption.

As a result, these proteins are not able to keep your blood in blood vessels, and the fluid is forced into spaces between your cells. The continued build-up of fluid in the spaces between cells causes swelling or edema in the stomach region.

This is also a form of severe protein malnutrition which is called kwashiorkor. It develops when an individual is consuming adequate calories but not enough protein.

Strengthens Immune Health

Proteins assist in forming antibodies, specifically known as immunoglobulins, that help fight infection, bacteria, and viruses.

When foreign damaging invaders enter your cells, your body produces antibodies that prevent viruses and bacteria from multiplying and overloading your body with the disease that they cause.

Your cells remembers when the body produces antibodies against a specific virus or bacteria. Thus, antibodies quickly responds to that particular disease agent, the next time it invades your body.

This results to your body’s immunity development against diseases to which it is previously exposed.

Transports and Stores Nutrients

Transport proteins carry substances, such as nutrients, throughout your bloodstreams. Meaning, it transports vitamins or minerals, cholesterol, blood sugar, and oxygen among others into, within, our out of cells.

Furthermore, proteins also have storage responsibilities. Examples of storage protein include Ferritin, which stores iron, and casein which is one of the principal protein in milk.

Provides Body with Energy during Exhaustive Exercise, Fasting, or Inadequate Calorie Intake

Even though carbohydrates and fats are much more suited for supplying energy to your body, protein can also do the same.

Our body widely uses protein that’s why it maintains and reserves carbohydrates and fats as fuel to our body. However, during fasting, inadequate calorie consumption, and extensive exercise, your body breaks down skeletal muscle. This enables amino acids to suppy you with energy.


Our ultimate protein guide isn’t stopping there. We got the second half of our 2-Part Ultimate Guide to Proteins which discusses its composition, counting guide, and proper consumption among others. What are your key takeaways? You can also check out one of our nutrition posts to learn more about vitamins and minerals that contribute to muscle growth and their easy-to-find food sources.