There are about two grams of zinc in the body where it is highly concentrated in the hair, skin, eyes, nails and testes. Zinc is a co-factor in many enzymes that regulate growth and development, sperm generation, digestion and nucleic acid synthesis. It is also a constituent of many enzymes involved in metabolism.

The human body's need for zinc is small but its role in growth and well-being is enormous and starts before birth. It is vital for healthy skin and hair, proper healing of wounds, successful pregnancies and male virility. It plays a essential role in guarding against diseases and infection and is also needed to transport vitamin A to the retina so is very important for eye health.

There are 156 enzymes that require zinc for their functioning and healthy growth and sexual maturity are just two of the many functions that depend upon zinc.

Copper, together with zinc improves the absorption of vitamin D, the vitamin which aids in the absorption of calcium.

Vitamins A and D support the absorption of zinc and zinc supports the absorption of all the fat-soluble vitamins such as vitamin A, D, E and K..

Many of the proteins involved in vitamin A metabolism and the receptors for both vitamins A and D only function correctly in the presence of zinc.

The same amount of iron and zinc should be consumed daily but they should never be taken together as they compete for absorption.

Zinc has been shown in recent studies to be especially useful in treating the common cold by making recovery quicker.

Zinc deficiency can result in alopecia (hair loss), depression, delayed wound healing, diarrhoea, frequent infection. growth retardation, impaired immunity, impaired senses, impotence, infertility, loss of hair, night blindness, photophobia, poor appetite, scaly skin inflammation, skin diseases and weight loss. Those suffering from rheumatoid arthritis may have a zinc deficiency.

Those drinking excess alcohol have low levels of zinc because alcohol decreases zinc absorption and increases urinary secretion of zinc. Diuretic medications also adversely affect zinc levels. If an individual ingests excessive amounts of caffeine, drugs or sugar, it is more than likely that a zinc deficiency will develop. Low zinc levels can cause liver deterioration and diminished functioning of the reproductive organs, immune system and skin.

Cadmium found in some foods and ingested through smoking tobacco displaces zinc in the body and can lead to a deficiency. .

A developing foetus requires a high amount of zinc, likewise, there is a high amount of zinc lost through breast milk after birth therefore pregnant and breast feeding women may need to consume extra zinc rich foods. Infants older than six months should eat age-appropriate foods which provide zinc as the amount in breast milk is no longer ample. See Nature Cures for babies

Gastrointestinal surgery, Crohn's disease, ulcerative colitis, short bowel syndrome and other digestive diseases can all decrease zinc absorption and increase zinc loss from the body. For unknown reasons 44% of children and 60-70% of adults with sickle cell disease have low levels of zinc.

Iron can interfere with zinc absorption and therefore, if iron supplements are absolutely necessary, they should be taken alone between meals. Too much phosphorous can cause diarrhoea and calcification (hardening) of organs and soft tissue and can interfere with the body's ability to use iron, calcium, magnesium and zinc. It is a matter of getting the balance right which is why supplementation is not advised.

Foods that contain these minerals will never overdose the consumer with phosphorous. Zinc supplements are not advised as they can upset the balance of other minerals in the body, for instance, excessive absorption of zinc can suppress copper and iron absorption.