- Part of your DNA – your genetic inheritance! Proteins combine with nucleic acids to form nucleoproteins, in the nucleus of every cell in your body;
- Enzymes – These are the proteins which make everything happen, e.g. to break down food for absorption; to regulate the entry of nutrients through cell walls, and the removal of waste-products; to grow, develop, move, reproduce. (Many enzymes also need specific vitamins and minerals to function);
- Haemoglobin – the protein which, with iron, carries oxygen around your body;
- Myoglobin and elastin – These are the two main proteins in muscle fibres;
- Bones are mainly proteins, with calcium, magnesium and phosphate;
- Hormones which send chemical messages between nerve cells and to regulate metabolism;
- Antibodies which circulate in your blood to protect you against viruses; and
- Keratin which forms your hair and nails
Protein is an important energy-yielding macronutrient meaning it provides us calories, or energy. Proteins build muscle and make up hemoglobin, which transports oxygen to our muscles. Proteins also have functional and structural roles building and repairing tissues. They are key players in signaling and chemical reactions as well including enzymes and hormones.
Through a microscope, proteins look a bit like necklaces with beads that come in different shapes and sizes. To further the analogy, think of each bead as a different type of amino acid: each protein in our body has a specific amino acid sequence, and proteins typically contain from 50 to 2,000 amino acids connected in various combinations. (That’s a lot of beaded necklaces!) What makes this interesting is that there are only 20 standard amino acid but proteins, and their functions, exist in a multitude of varieties because of which amino acids are present and in what order they are put together.
As our body is not able to store amino acids in the way it can with carbohydrates and fats, we need to make sure we obtain it daily through what we eat, from:
- Animal sources, such as meat, fish, eggs and dairy products - these contain the full range of essential amino acids
- Nuts, grains, legumes and tofu – individually these don’t contain the full range of amino acids, so a combination of different types should be eaten
- Protein-containing nutritional supplements – useful in ensuring protein needs are met if the diet may be inadequate.
Protein needs vary from person to person depending on their health, activity and body composition. Protein needs are higher during growth, pregnancy or healing, during an exercise or weight lifting program, and when overall calories are depleted (to prevent muscle break down).
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