Zinc deficiency has been shown to be associated with growth retardation in humans. The growth retardation may be accompanied by a lowered taste acuity and a reduced accumulation of zinc in the tissues of the body. In particular, concentrations of zinc in hair may fall with zinc deficiency. Studies have assessed the associations between growth retardation, low hair concentrations of zinc and poor taste acuity in children. For example in one study1, researchers investigated a group of 9 to 12 year old school children with below average levels of zinc in their hair. The results of the study showed that there was a significant association between low zinc concentrations in the hair of the children and short stature. Further, examination of the taste acuity of the children showed a significant association between low zinc concentrations in the hair of the children and hypogeusia. Therefore these results confirm that associations exist between growth retardation, zinc hair levels and taste acuity in children.
Interestingly, the children with below average levels of zinc in their hair were the most likely to have poor nutrition. Hair mineral analysis is an accepted method of assessing zinc status, and is generally accepted to be an accurate assessment of zinc nutriture over the long term. Plasma zinc on the other hand is considered a more short term measure of zinc status. The fact that the hair levels of zinc were low in these children therefore suggests that they may have had chronically low levels of zinc and this may explain their shorter than average stature. Hair levels below 70 ppm are usually considered representative of poor zinc nutrition. In the case of the children in this study, many were at the lower limit of this level, although none had outright zinc deficiencies. Other studies assessing zinc nutrition in children have found similar values in children from low income families. This supports accumulating evidence that poor socioeconomic groups are at greater risk of chronically poor nutrition which can lead to disease.
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