Elsevier

Nutrition

Volume 22, Issue 1, Supplement, January 2006, Pages S26-S32
Nutrition

Effect of micronutrient supplement on health and nutritional status of schoolchildren: mental function

https://doi.org/10.1016/j.nut.2004.07.021Get rights and content

Abstract

Objective

We evaluated the effect of a micronutrient-fortified beverage on mental function in schoolchildren.

Methods

This double-blind, placebo-controlled, matched-pair, cluster, randomized feeding trial assessed baseline before supplementation and after 14 mo in a cohort of 608 children aged 6 to 15 y who received a micronutrient-fortified beverage or placebo. Children in two classes (clusters) in each of nine grades were assessed for intelligence, attention and concentration, memory, and school achievement.

Results

Mean intelligence quotient scores of the micronutrient-fortified beverage group and the placebo group at baseline and final follow-up were not significantly different. Mean verbal and performance scores and increments were also not different. After supplementation, attention-concentration increment scores of the micronutrient group were significantly higher (P < 0.05) than those of the placebo group. Mean and incremental scores of the supplemented group on the memory scale were not significantly different from those of the placebo group.

Conclusions

Supplementation with a beverage fortified with a range of micronutrients significantly improved attention-concentration over 14 mo, but not intelligence quotient, memory, or school achievement among middle-income schoolchildren.

Introduction

Early stimulation, socioeconomic status, home environment, nutritional status, and interactions between parent and child influence the mental function of growing children [1], [2]. Although studies among children and adolescents in India and abroad have indicated that micronutrient status and cognitive functions are positively associated [3], [4], [5], [6], the effect of supplementing a beverage with multiple micronutrients on mental function has not been previously reported.

Studies on supplementation with multiple micronutrients to children with or without subclinical micronutrient deficiencies in developed countries are divided on whether it benefits intellectual performance [6], [7], [8], [9], [10], [11], [12], [13]. Among a group of 6- to 15-y-old schoolchildren given a multiple micronutrient supplement in doses of 50%, 100%, and 200% of the recommended dietary allowance (RDA) according to the U.S. Department of Agriculture [14], only those provided with 100% of the RDA demonstrated a significant improvement in non-verbal intelligence [11]. There was no effect on verbal or crystallized intelligence. A selective response to non-verbal tests was predicted due to the fact that they better represent biological functioning than do verbal tests. However, only children with lower dietary micronutrient intake responded to supplementation [11], suggesting the presence of subclinical deficiencies. Interestingly, two studies that followed similar methodologies found no significant improvement in intelligence quotient (IQ) [8], [9]. Micronutrient supplementation has also been associated with improved attention and concentration [7] and, in children with attention deficits, increased the time these children spent concentrating [12].

None of the studies reviewed had used food as a vehicle for providing micronutrients as per the RDA. The previous evidence concerned micronutrient supplementation through the provision of tablets or capsules. Moreover, studies tended to evaluate development before and after intervention.

The present study tested the hypothesis that micronutrient supplementation of a fortified beverage would improve primary outcomes such as IQ, memory, attention-concentration, and school achievement over time in residential schoolchildren who had no overt signs (i.e., signs not physically visible) of deficiency and adequate macronutrient intake (>75% of the RDA). The secondary hypothesis was that micronutrient supplementation would improve the constituents of primary outcomes, i.e., verbal and performance IQs and school marks on math, science, and social studies whether or not overall IQ, memory, attention-concentration, or aggregate school marks improved. The secondary hypothesis was considered important because previous studies [4], [13] have indicated that verbal IQ and fluid intelligence (performance IQ) improves after supplementation even when IQ remains unchanged.

Section snippets

Materials and methods

A double-blind, placebo-controlled, matched-pair, cluster randomized study was undertaken in children who were 6 to 15 y old and in grades 1 to 10 from two residential schools that catered to middle-income semi-urban children near Hyderabad, India. The experimental design, randomization, the sample covered for assessing mental function, and statistical analysis have been published previously [22].

The following culture-appropriate standardized tests were administered to the children.

Results

Results of follow-up data on mental functions from the cohort of 680 children ages 6 to 15 y are presented in this report. Initially, 814 children who also had been measured for their heights and weights completed the baseline assessment on mental tests.

Of 814 children, 206 dropped out (∼25%; graduation from school, n = 53; migration and missing follow-up, n = 153). Mean IQ scores of all those who did not complete follow-up in the micronutrient (n = 100) and placebo (n = 106) groups were

Discussion

The effect of supplementation on a psychological domain may not be observable by an assessment of global IQ. For example, a child might be better in numerical ability and poor in language but that child’s IQ may be average or even above average. However, the present results indicated no significant differences in IQ and its subtest scores between study groups. The large increase in IQ points in both groups (about eight points) could be attributed in part due to the practice effect over time.

Conclusion

The results of this study suggest that supplementation with a beverage that is fortified with a range of micronutrients could significantly improve mean incremental scores of children on the attention-concentration test but not IQ, memory, or school achievement scores.

Acknowledgments

The authors acknowledge the support and encouragement received from Kamala Krishnaswamy, M.D., National Institute of Nutrition (ICMR), the guidance received from Nadamuni Naidu, M.Sc., National Institute of Nutrition, and our consultants Saroj Arya, Ph.D., National Institute of the Mentally Handicapped, Hyderabad, India and K. Ravichandra, Ph.D., Osmania University.

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    This study was supported by GlaxoSmithKline Consumer Healthcare Ltd., India.

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