Micronutrients such as vitamin A, iron and zinc, have positive effects on child immunity, while multivitamin and multimineral supplements can improve the immunity of the older generation.
1. Child immunity
It has been repeatedly demonstrated in many research studies throughout the world, including South Africa, that vitamin A can reduce child mortality. In certain vulnerable populations child deaths due to various causes, including infections like measles, respiratory infections and diarrhoea, can be reduced by up to 23% by supplying these children with an adequate vitamin A intake.
Diarrhoea is a deadly disease, that causes the death of countless young children worldwide, and particularly in Africa. A recent study conducted in Tanzania showed that children who had been admitted to hospital with pneumonia and treated with vitamin A supplements were 44% less likely to develop diarrhoea for a whole year after leaving the hospital, than children who had been given a ‘dummy’ supplement which did not contain vitamin A.
Some evidence is also emerging that the use of vitamin A supplements and of vitamin A fortified food may boost immunity and reduce the risk of infections such as malaria.
Iron deficiency is still one of the most prevalent deficiencies in developing countries and children are particularly vulnerable. Iron plays an important role in boosting immunity via a number of important enzymes and immunity factors. However, there is still controversy about the use of iron supplements because a number of studies showed that such supplements were paradoxically linked to an increased risk of infections in certain study groups.
Recent studies in Africa have found iron supplementation to be safe and effective. However, researchers caution that iron supplements should be withheld in children suffering from severe protein-energy malnutrition, very-low-birth-weight infants and children with bacterial infections. Clearly more research will have to be done to define exactly how iron helps to improve immunity and what doses should be used.
Zinc is another vital micronutrient that is implicated in immune function. Research findings indicate that large numbers of children in developing countries are exposed to zinc deficiency because they eat cereal-based staple diets which have a low zinc content. Zinc is known to play an important role in normal growth, boosting immunity and increasing antibody production.
Research findings from studies conducted in India, Peru, Bangladesh and Ethiopia now show that zinc supplements significantly reduce the severity and duration of childhood diarrhoea, mortality due to diarrhoea, anorexia, vomiting, fever and cough in malnourished children.
2. The Older Generation
Elderly people are known to be susceptible to infections and possibly also to autoimmune diseases as a result of reduced immune function. Researchers are currently investigating the effects of multivitamin and multimineral supplements on this loss of immune function in the elderly and have found that the use of such supplements does indeed boost depleted immune reactions. Elderly subjects reduced the number of days they were ill by 25 days a year when they took these supplements. Use of antibiotics was also reduced and susceptibility to infections was significantly less.
An interesting finding of these studies was that the beneficial effect of taking vitamin and mineral supplements was greatest when those older people who were exposed to the greatest risk of falling ill because of malnourishment were given the supplements. It was also evident that the supplements had to be taken for long periods (6 months or more) to achieve the desired effect.
3. What does this mean?
In practical terms, the research findings described above indicate that anyone who is eating a monotonous diet based on a refined staple food such as sifted, refined maize meal or white bread, who is malnourished , very young or old, should be given certain micronutrient supplements. Feeding schemes and food fortification are the responsibility of Governments, but all of us can keep this information in mind and act upon it.
If you or your children or the elderly members of your family are constantly ill with diarrhoea, or respiratory infections, or if symptoms such as lack of appetite, tiredness, and low immunity appear, then it may be a good idea to think of using micronutrient supplementation.
A word of warning: Please don’t fall into the trap of thinking that “If a small amount of vitamin A, iron, zinc, etc, helps to boost immune function, then taking 5 x, 10 x, 100x the dose will be even better!” This is not true and can be as harmful as the original deficiency. Stick to the dosage instructions - if the label recommends 5 drops, or ½ a teaspoon of multivitamin syrup for children , and 1 tablet of multivitamin and multimineral supplement a day for adults - then this is the correct dose - don’t take more than is recommended. - (Dr I.V. van Heerden, DietDoc)