1. Growth & Maintenance
Your body need protein for growth and maintenance of tissues. Your body breaks down more protein than it can create, thus increasing your body’s needs. This typically happens in periods of illness, during pregnancy and while breastfeeding. People recovering from an injury or surgery, older adults and athletes require more protein as well
2. Causes Biochemical Reactions
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 that are essential to your metabolism. Enzymes may also function outside the cell, such as digestive enzymes like lactase and sucrase, 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:
- Energy production
- Blood clotting
- Muscle contraction
3. Acts as a Messenger
Some proteins are hormones, which are chemical messengers that aid communication between your cells, tissues and organs. Hormones can be grouped into three main categories:
- Protein and peptides: These are made from chains of amino acids, ranging from a few to several hundred.
- Steroids: These are made from the fat cholesterol. The sex hormones, testosterone and estrogen, are steroid-based.
- Amines: These are made from the individual amino acids tryptophan or tyrosine, which help make hormones related to sleep and metabolism.
Protein and polypeptides make up most of your body’s hormones. Some examples include:
- Insulin: Signals the uptake of glucose or sugar into the cell.
- Glucagon: Signals the breakdown of stored glucose in the liver.
- hGH (human growth hormone): Stimulates the growth of various tissues, including bone.
- ADH (antidiuretic hormone): Signals the kidneys to reabsorb water.
- ACTH (adrenocorticotropic hormone): Stimulates the release of cortisol, a key factor in metabolism.
Some proteins are fibrous and provide cells and tissues with stiffness and rigidity. These proteins include keratin, collagen and elastin, which help form the connective framework of certain structures in your body. Keratin is a structural protein that is found in your skin, hair and nails. Collagen is the most abundant protein in your body and is the structural protein of your bones, tendons, ligaments and skin. Elastin is several hundred times more flexible than collagen. Its high elasticity allows many tissues in your body to return to their original shape after stretching or contracting, such as your uterus, lungs and arteries
Protein plays a vital role in regulating the concentrations of acids and bases in your blood and other bodily fluids. One way your body regulates pH is with proteins. An example is hemoglobin, a protein that makes up red blood cells. Hemoglobin binds small amounts of acid, helping to maintain the normal pH value of your blood.
Proteins in your blood maintain the fluid balance between your blood and the surrounding tissues.
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. Once your body has produced antibodies against a particular bacteria or virus, your cells never forget how to make them. This allows the antibodies to respond quickly the next time a particular disease agent invades your body. As a result, your body develops immunity against the diseases to which it is exposed
Transport proteins carry substances throughout your bloodstream — into cells, out of cells or within cells. Proteins also have storage roles. Ferritin is a storage protein that stores iron. Another storage protein is casein which is the principal protein in milk that helps babies grow.
Proteins can supply your body with energy. Protein contains four calories per gram, the same amount of energy that carbs provide. Protein can serve as a valuable energy source but only in situations of fasting, exhaustive exercise or inadequate calorie intake.
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.
Below I’ve attached two studies regarding the importance of protein during pregnancy & breastfeeding.