The article on ‘Effect of Iron and Zinc deficiency on short term memory in
children’ [1] is an eye opener, as micronutrient malnutrition and its ill
effects are rampant in our country. Iron deficiency anemia is the most
common nutritional disorder, even in the current era. Iron is essential
for oxygen carrying, muscle functions, immune function and brain
myelination, neurotransmission and cognitive functions [2]. Even mild to
moderate anemia in infancy and early childhood are known to leave a
permanent signature on the growing brain. Iron has effects on the
neurotransmitters like dopamine and probably serotonin [2]. Iron
deficiency reduces dopaminergic receptors and the reduction in
dopaminergic receptors leads to increase in opiate receptors and resultant
defective learning ability and cognition. The role of iron deficiency on
aggravating breath holding spell, febrile seizure, and hypercyanotic blue
spell are also being increasingly observed in clinical practice.
Similarly, zinc is essential for enzyme function, metabolism, immune
function, taste sensation, reproduction, cognition and retinal function
[3]. The findings of the above study prove robust evidence in this
context.
However, data regarding how many children had
malnutrition, how many had anemia, the distribution according to
hemoglobin level, severity of iron and zinc deficiency are lacking in the
presentation [1]. Serum protein level, that may be a confounder while
interpreting serum zinc level, is to be evaluated in such a study. It is
also interesting to know whether deworming was given prior to iron
therapy, as the role of parasitic infestation in deficiency is discussed
in the presentation. Deworming is essential to break the negative spiral
of worm infestation, malnutrition and altered immunity [4].
The dose of iron 2 mg/kg/day and zinc 5 mg/day is
suboptimum to treat deficiency state. The authors have not given any
explanation for choosing prophylactic dose for treatment. The reference
endorsing the selection of 6-8 years and 9-11 years as the age for
cultivating inspiration and wisdom and for formative process and
reasoning, respectively, as cited in the concluding paragraph is also
missing.
References
1. Umamaheswari K, Bhaskaran M, Krishnamurthy G,
Hemamalini , Vasudevan K. Effect of iron and zinc deficiency on short term
memory in children. Indian Pediatr. 2011;48:289-93.
2. Beard JL. Iron biology in immune function, muscle
metabolism and neuronal functioning. J Nutr. 2001;131:5685-795.
3. Bhatnager S, Taneja S. Zinc and cognitive
development. Br J Nutr. 2001;85:S139-45.
4. Koski KG, Scott ME. Gastrointestinal nematodes, nutrition and
immunity: Breaking the negative spiral. Annu Rev Nutr. 2001;21:297-321.