Zinc and Eye Health

Zinc's role in alleviating macular degeneration has been thoroughly studied. Its deficiency causes deterioration of the macula. This important mineral aids in healing and is a constituent of at least twenty-five enzymes involved in digestion and metabolism. It helps vitamin A to be released from the liver so it can be used in eye tissues.

Zinc is also essential for a healthy immune system, helping to fight major infections as well as less serious ones, such as boils, acne and sore throats. Without zinc, the body is unable to repair damaged tissues or heal wounds. It plays a major role in cell division, so the tissues that grow throughout life, such as hair, skin and nails, need it to remain healthy. Zinc is also vital for normal growth in children and for their sexual development.

Availability in food

Zinc is present in a wide variety of foods and, like iron, appears to be better absorbed when it comes from animal sources such as muscle meats, fish and seafood. Good vegetable sources include whole grains, nuts, seeds, ginger root and brewer's yeast. Despite being present in so many foods, zinc is often deficient in today's diet because up to 80 per cent of zinc can be lost in the milling process, and it leaches into cooking water. Many soils have become depleted in zinc following the widespread use of chemical fertilizers.

What if your intake is too low?

Serious deficiency leads to a poorly functioning immune system with increased likelihood of infections and allergic conditions, slow healing of wounds, night blindness, loss of smell and taste, falling hair, rashes and other skin problems, white spots on the fingernails, mental lethargy and sleep disturbance. Men may become infertile, and periods may be irregular in women. In children, growth may be stunted and sexual maturity delayed.

When extra may be needed

  • If you are a man (See also Zinc for men)
  • If you are on a calories restricted diet, including slimming or if you are an older person with a small appetite
  • At times of particular stress
  • If you perspire excessively, and especially if you exercise or take part in sport regularly
  • When taking the birth-control pill, diuretics (water tablets) or if you are receiving hormone replacement therapy
  • If you regularly drink moderate to large amounts of alcohol, tea or coffee, or smoke
  • If you are a vegan or strict vegetarian
  • During pregnancy and when breast feeding
  • If you have psoriasis (rapid turnover of skin can deplete zinc)
(Pregnant and breast feeding women should consult a doctor, midwife, or qualified nutritionist before taking any mineral or vitamin supplement.)

Can too much be toxic?

Zinc is relatively non-toxic in doses up to about 100mg, although it may cause some nausea or diarrhoea. Excessive supplementation can cause dizziness, drowsiness and hallucinations.

To be most effective, zinc needs to be accompanied by adequate levels of calcium, copper, phosphorus, selenium and vitamins A, B6 and E

Using a supplement

If you wish to take a supplement, take it at bedtime on an empty stomach, because zinc supplements can interfere with the absorption of other essential minerals, especially iron and copper. If you take a multi-mineral preparation