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Functions of protein

Structure – Protein is a building block of our body tissue and is a structural component of every cell in our body, therefore it is important for growth and repair. It makes up half the body’s dry weight and is the second most abundant compound after water. It is a primary component of muscle, hair, skin, nails, eyes as well as internal organs. Organs such as the heart and gut are made up of muscle fibers as well a skeletal muscle, hence muscle is essential for health as well as overall fitness and strength. Collagen is also a protein which makes up extracellular matrices, essential for bone, joints and cartilage.

Repair and growth – as proteins are fundamental structural and functional elements within every cell of the body, they are essential for growth and repair. Protein deficiency is associated with stunted growth in children especially from low income families and developing countries. We require a constant supply of amino acids to build proteins that create our body tissues. This is true from pregnancy as well as growing children. However, we are constantly repairing, breaking down and regenerating body tissues. During times of healing, illness, following surgery, injuries and burns, a higher amount of protein production is required. Therefore, protein deficiency can increase healing times or prevent adequate healing and repair.

Hormones/neurotransmitters/enzymes – amino acids (building blocks of protein) and proteins are precursors to hormones, enzymes and neurotransmitters

Tryptophan – converted to 5HTP which is then converted to serotonin and then melatonin when exposed to darkness, thereby supporting mood and sleep Tyrosine – is important to produce thyroid hormone (thyroid hormone is made up of tyrosine and iodine), also the neurotransmitter dopamine which is essential for mood, motivation and movement, dopamine is then converted to noradrenaline Insulin – is made from a protein composed of 2 chains Enzymes – essential for normal bodily processes including digestion are complex proteins Haemoglobin, antibodies and other transport proteins – produced from amino acids Liver conjugation– amino acids are required for phase 2 liver conjugation. Adequate amounts of protein with special attention to glycine, l-glutamine, methionine, l-cysteine and N-acetyl-cysteine along with inorganic selenium and addition of taurine very important in the support of phase 2 activity. 1

Satiety – protein is broken down into energy more slowly than carbohydrate and has been shown to delay stomach emptying, making people feel fuller for longer. As it is broken down more slowly it can reduce the insulin response even when combined with carbohydrates, therefore it can support insulin sensitivity and therefore reduce sugar and carbohydrate cravings. Protein also triggers satiety neuropeptides including GLP-1, increasing feelings of satiety and fullness. Therefore, including protein in every meal is associated with reduced carbohydrate carvings as well and caloric intake in some circumstances, as well as a reduce insulin response which can encourage fat loss.