A new US study suggests that school-age children with vitamin A deficiency appear to be more likely to get gastrointestinal and respiratory illnesses.
Over the period of one year, the observational study measured blood micronutrient concentrations of
2774 children aged between 5 and12 years and documented cases of gastrointestinal and respiratory illnes- ses, such as diarrhea with vomiting, cough with fever, earache or ear discharge with fever (1). The study results showed that, compared to children with an adequate vitamin A (retinol) status (above 30.0 mcg/dL), participants with vitamin A deficiency (below 10.0 mcg/dL) had a significantly increased risk of developing diarrhea with vomiting and cough with fever. The association followed a dose-response pattern in that higher blood concentrations of retinol were related to fewer symptoms: every 10 micrograms per deciliter of retinol in blood was associated with 18% fewer days of diarrhea with vomiting, 10% fewer days of cough with fever and 6% fewer doctor visits. Zinc, erythrocyte folate and vitamin B12 status were not associated with the risk for illnesses or doctor visits.
The researchers commented that vitamin A deficiency is still an important public health problem in many countries worldwide. Whether vitamin A supplementation reduces the risk or severity of infection in children over five years of age needs to be determined. Earlier studies on vitamin A supplementation in preventing illnesses in younger children have generated inconsistent results. This indicates that effects of micronutrients, including retinol, could vary in different settings due to the underlying nutritional status of the population, the microorganisms that cause illness - whether viral, bacterial or parasitic - the age and possibly sex of child- ren, as well as other factors.