Zinc is an essential trace element. The normal and best routes for zinc intake are foods including nuts and seeds, cereals and certain meats and shellfish. However, increasingly it is being shown that many of those who live in Western countries are deficient in zinc. The function of zinc in humans is varied as it acts as a cofactor for a large number of enzymes. Zinc deficiencies therefore negatively affect a large number of metabolic pathways and this can have wide reaching effects on health over the long term. The elderly are at particular risk of micronutrient deficiencies because as individuals age their ability to absorb nutrients declines. In addition, many elderly individuals consume low quality diets, especially if they are institutionalised. Studies show that elderly individuals who have a poor zinc status are more susceptible to infections such as pneumonia, and may have a significantly elevated risk for mortality compared to those with an adequate zinc status. Generally zinc deficiencies have been shown to impair immunity including T cell numbers.
There is a common misconception held by many that dietary supplements are not effective. Many claim they are a waste of money and they may even be harmful. This relates to studies showing that some dietary supplements do not show positive health effects in healthy individuals. However, it should be remembered that dietary supplementation is designed to be used as an adjunct to a healthy diet. Supplements are there to ‘supplement’ the diet with factors that may be present in low concentrations or absent. Clearly supplementing with zinc will have little effect in a healthy individual who does not have a zinc deficiency. And if fact in such an individual taking zinc supplements may have unintended consequences through for example the inhibition of the absorption of other minerals such as copper. However, those with low intakes of zinc and those with a poor zinc status may benefit from a zinc supplement. Correcting a deficiency through taking a supplement clearly supplies a health benefit. A zinc deficiency can cause a significant reduction in immune function, and in individuals experiencing such a deficiency, zinc supplements may improve immunity. How many individuals in the Western population are zinc deficient and how many have poor immunity as a result? Current estimates from studies suggest that large numbers are deficient in not just zinc but also other minerals. Supplements are beneficial to these individuals. Those with the poorest diets will benefit the most from supplements.
Studies have investigated the effects of zinc supplement on the elderly to assess if they are able to have beneficial health effects For example, in one study, researchers administered 30 mg of zinc per day as zinc gluconate to a group of elderly (over 65 years) individuals in a nursing home. Assessment of the zinc status of the study population revealed that 58 % had a zinc deficiency (serum zinc <70 μg/dL) prior to supplementation. After 3 months of supplementation the individuals receiving the zinc supplement had experienced significant improvements in serum zinc concentrations, compared to the placebo group. In this regard, serum zinc concentrations had increased by 16 % more in the zinc supplement group. However, some of the subjects with the lowest zinc concentrations failed to obtain serum levels above 70 μg/dL even with supplements. Those subjects who experienced increased serum zinc levels also experienced significant increases in the number of peripheral T cells, suggesting immunity had improved.
Eat Well, Stay Healthy, Protect Yourself
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