Almost all minerals are found in the human body and 15 of them are known to be essential. They will be absorbed in the right amounts in a properly balanced diet, but most of the trace elements and iron and zinc are poisonous if extra is eaten.
- Potassium is essential to maintain the right balance of acids and alkalis in the body. It is needed in order to excrete excess acid. Low levels of potassium in the diet are linked to high blood pressure and an increased risk of stroke. Good sources are tomato, strawberries, banana, other fruit, yogurt, cheese, potatoes, soya products, whole grain cereals, nuts, black treacle. Deficiency is unlikely to occur on the diet described by this book unless diuretics or purgatives are taken, or in cases of diarrhoea linked to malnutrition.
- Iron is needed for the production of red blood cells, for muscle tissue and for handling oxygen in many other cells. Good sources are liver, red meat, fish, raisins and sultanas, green vegetables. Tannins from tea and an excess of wheat fibre can reduce the uptake of iron.
- Magnesium is needed for healthy bones, nerves and muscle. Good sources are nuts, raisins and sultanas, banana, soya products. Deficiency is rare except in cases of severe diarrhoea.
- Zinc is needed for the growth of all healthy tissue, muscle and bone and for the healing of wounds. Good sources are red meat, liver, hard cheese but zinc uptake is reduced if cereal fibre is eaten at the same time, Wholegrain cereals also contain useful levels of zinc.
- Phosphorus is an important part of all healthy cells, especially bones and teeth. Good sources are meat and other proteins.
- Calcium is needed for healthy bones and teeth. Good sources are milk and cheese, yogurt, wholegrain cereals, pulses, vegetables, raisins and sultanas. Vitamin D is essential for the correct uptake of calcium from the diet. Wheat fibre also reduces calcium uptake.
- Sodium and chloride are both essential elements for muscle and nerve activity, but in very small amounts. A diet rich in processed foods is likely to contain excessively high sodium levels and increase the risk of high blood pressure.