Function of Protein
Growth & Repair
Growth and repair just wouldn’t happen without protein. Any time we cut or injure ourselves, protein is there to help stitch it up; when we are developing during childhood and adolescence, protein enables us to grow to our full potential; and when we’re walking, running or lifting, protein makes sure that we have the muscles to do so, if not it can help us to build more. Without adequate protein, growth would come to a halt and repairs would go unfixed.
Enzymes, Hormones and Antibodies
Proteins make enzymes, hormones and antibodies. Enzymes and hormones are there to control every process in our body. Enzymes catalyze biochemical reactions by initiating or increasing the rate of the reaction. These reactions are what drive many of the functions in our body. This includes the digestion and metabolism of fats, sugars, proteins and alcohol. Enzymes are also involved in the replication of DNA. Our DNA is our unique blue print that determines everything in our body, from the inside out. This is an ongoing process that regenerates new cells as the old ones die, and it’s essential in reproduction and heredity.
Hormones are chemicals released by glands or cells. They send messages from one part of the body to another and this helps to regulate many processes in our body. This includes hormones that control hunger and appetite; sleep-wake patterns; fight or flight hormones; reproductive hormones; hormones that control growth; and those that influence our moods. Every part of our body takes orders from this complex system of enzymes and hormones, and they’re made of amino acids.
Antibodies are proteins that protect the body from antigens. They support the function of our immune function.
Structural and Transport Proteins
Structural proteins are essential components of every cell in our body. They add structure, and support to cells, and allow for processes such as muscles contractions. They also form proteins like collagen, elastin, cartilage, and keratin.
Transport or carrier proteins come in two forms. There are the proteins found in cell walls that are involved in the transport of water, nutrients and ions into and out of our cells. This helps to maintain the balance of nutrients and water in our cells and blood stream. Then there are carrier proteins that offer transport around the body. Hemoglobin is a good example of this. It’s a protein found in red blood cells that transports oxygen from our lungs to the rest of our body.
Hair, Skin and Nails
Protein gives the strength to our nails, the structure to our hair, and it helps to maintain the integrity of our skin. Collagen, elastin and keratin are proteins that give structure and elasticity to our skin. Keratin is also the structural protein in our hair and nails. Adequate dietary protein is needed to build these proteins and therefore, maintain the health of our hair, skin and nails.
Source of Energy
Protein, like carbohydrates and fats, can also contribute a source of energy to our diets. In normal circumstances, protein will provide only 15%-20% of our daily energy needs. The rest of our energy comes from carbohydrates (~50%-65%) and fats (~20%-30%). Protein is best spared for its many other functions in our body.
Essential & Non-Essential Amino Acids
We need 22 different amino acids in our body and they can be divided into two groups. Essential and non-essential. The essential amino acids must be obtained from our diet. Our body can not manufacture these for itself. The non-essential amino acids can be manufactured by our body, providing we consume all the essential amino acids and the other required nutrients. If we include a balance of unrefined plant and animal proteins in our diet, or for vegetarians, combine a good variety of plant proteins, then we'll be able to meet our nutritional needs.
Sources of Protein
Sources of Essential Amino Acids
• Red meat
• Fish and seafood
Sources of Non-essential Amino Acids
• Grains - rice, wheat, oats, rye, barely
• Legumes and lentils
• Nuts and seeds
How much is enough?
We need to consume approximately 55g/2oz protein for men, and 45g/1.5oz protein for women, each day. This amount varies from one person to the next and is further determined by our age, gender, height and weight, how physically active we are, pregnancy, and other preexisting medical conditions.
Ideally, this protein is divided up over the day. If we consume a source of protein with each meal to satisfy our daily needs, then this will give us a balanced meal, and provide us with a constant supply of amino acids.