Calcium is important for building healthy bones and teeth, and also plays an essential role in nerve and muscle function and blood clotting. It keeps muscles moving smoothly and prevents cramping. Approximately 99 per cent of the calcium in your body is present in the bones, teeth and skeleton; the other 1 per cent is found in and around cells. You will find calcium in milk and milk products; calcium-fortified foods; the bones of fish like sardines and salmon; tofu, spinach and oatmeal. Phosphorus works with calcium to help build bones and teeth. It is used in the energy cycle and helps in the formation of red blood cells. It is found everywhere in foods with more being added during food processing and in plant fertilisers. Some of the best places to get phosphorus are high-protein foods like meat, fish, poultry, eggs, nuts, seeds, whole grains and milk.Magnesium is a wonderful mineral that is involved in just about every biological process in the body. It is essential for nerve and muscle function and the renewal of proteins, and is needed to make body tissues, particularly your bones. Main food sources are whole grains and legumes, green leafy vegetables, nuts, mushrooms and bananas. Much magnesium is lost during food processing, so use stone-ground wholemeal flour or brown rice.Sodium is one of the few minerals that we easily have in excess in our diets. Fourteen to 28 g of sodium chloride (salt) per day is considered excessive, but not uncommon in developed countries (1 teaspoon = approximately 5 g). Ten per cent of daily sodium comes from the natural salt content of foods. Fifteen per cent of salt is added during cooking or at the table, and a whopping 75 per cent of salt is added during the processing and manufacturing, as it also acts as a preservative.