Pre-adolescent children receiving the zinc bis-glycinate + multivitamin supplements gained an average of 1.3 cm more in height than children consuming the placebo over a six month period, according to findings published in Pediatrics International .
“Zinc plus multivitamin supplementation improved linear growth (height) in healthy school-aged Thai children especially in preadolescent (less than 10 years old) regardless of their baseline height and weight status. It also improved weight in children lighter than the average Thai standards,” wrote Sanguansak Rerksuppaphol and Lakkana Rerksuppaphol from Srinakharinwirot University.
The authors also note that no significant adverse events were reported.
Zinc is an essential micronutrient required for many biological processes, including growth and development, neurological function and immunity. It is naturally found in protein-rich foods such as meat and shellfish, with oysters among the highest in zinc content.
Deficiency of the micronutrient is a global problem, and Thailand, where the new study was located, is classified as a medium risk country for zinc deficiency, meaning that the estimated prevalence of zinc deficiency there is over 40%.
While zinc is well-known to be important for growth and development, efficacy studies of of zinc supplementation for growth enhancement have yielded inconsistent results.
For the new study, the researchers recruited 140 healthy Thai schoolchildren aged between 4 and 13, and randomly assigned them to receive either placebo or zinc bis-glycinate (providing 20 mg elemental Zinc) plus multivitamins (vitamins A, B1, B2, B6, B12, nicotinamide, and vitamin D) five days per week for six months.
“We used chelated zinc that has higher absorbability compared to ionic zinc,” explained the researchers. “Inorganic forms like sulfate have low bioavailability and higher incidence of gastrointestinal side effects. In addition, we supplemented multivitamins at RDA levels along with zinc to ensure that children had sufficient intakes of all vitamins without getting exposed to high doses with potential pharmacologic effects.”
Results showed that the children in the zinc + multivitamins group gained an average of 4.9 cm in six months, compared with 3.6 cm in the placebo group. The extra height gains were observed only after 2 months of supplementation, they said.
“Larger multi-site trials and alternative methods of delivery like food fortification should be considered to improve the growth of school children in endemic areas of zinc deficiency,” they concluded.
Source: Pediatrics International
Published online ahead of print, doi: 10.1111/ped.13011
“Effect of zinc plus multivitamin supplementation on growth of school children”
Authors: S. Rerksuppaphol, L. Rerksuppaphol