Researchers from the Netherlands Organization for Scientific Research (NWO) discovered that children in South east Asia had better resistance to disease if they took extra zinc in addition to Vitamin A and iron supplements.
In the past, zinc was largely ignored due to the difficulty in measuring zinc levels in the blood. Scientists now know that zinc deficiency leads to a reduction in the number of white blood cells and that a lack of vitamin A weakens the cell's immune response.
The researchers found that the reactions of children's immune systems to shortages of vitamin A, iron and zinc could be countered by dietary supplements. Zinc deficiency is often seen in developing countries where people eat a lot of cereals, pulses and vegetables but no animal products. This sort of diet contains lots of phytates, which bind iron and zinc, making it difficult for the blood to absorb them.
Scientists now believe that zinc deficiency could be as common as iron deficiency, which affects half of all pregnant women in developing countries.
Remarking on dietary necessity of zinc, Dr Wendy Doyle, of the British Dietetic Association, said, "Zinc is essential for making new body proteins including cell growth and brain development in the unborn baby.
It comes from a variety of foods but is most easily absorbed from foods of animal origin such as meat, seafood and poultry. Since iron can interfere with zinc absorption, it would make sense in communities where zinc intakes are likely to be low, to provide a supplement that contained both iron and zinc.