The long-term impacts of multiple micronutrient supplementation in children aged 24 to 59 months in Pakistan

This non-randomised, community-based clinical trial evaluated the effect of a locally produced micronutrient powder (Vita-Mixe) on micronutrient status (zinc, vitamin A, and vitamin D), haemoglobin level, and growth parameters in children aged 24-59 months. The trial took place in a low-resource, rural area in Kurram, Pakistan between January 2018 and June 2019 as part of a broader clinical trial, 'Ready to Use Supplementary Foods to Prevent Stunting Among Children Under Five Years in Kurram Agency'. Children aged 24-48 months were recruited and assigned to either an intervention or control arm. One sachet of micronutrient powder (1g) was given to the 111 enrolled children in the intervention arm (n=58) every other day for 12 months. The intervention provided an additional 50% of the reference nutrient intake per day for each micronutrient. Using blood samples taken at baseline and one year after the intervention, micronutrient and haemoglobin levels were assessed.

The study compared changes in the intervention group and control group. Results showed that children in the intervention arm had an average 7.52 ng/mL (p <0.001) increase in plasma vitamin A, a 4.80 ng/mL (p <0.002) increase in vitamin D, and a 33.85 µg/dL (p <0.001) increase in zinc, as well as a 2.0g/dL (p <0.001) increase in haemoglobin count. Significant improvements were observed in weight-for-height z-scores and weight-for-age z-scores in the intervention group (p <0.001), although no statistically significant changes were observed in height-for-age z-scores in the intervention group (p = 0.93).

The researchers concluded that one-year supplementation of micronutrient powder is a cost-effective and scalable intervention for food-insecure areas/households to address the alarming rates of undernutrition in Pakistan and other developing countries. The authors highlighted that uninterrupted micronutrient powder supply, compliance, and no loss to follow-up were among the strengths of their study.

The non-random allocation of participants may have introduced selection bias into the study. This was done to prevent contamination between intervention and control arms - as participants were allocated by distinct regions - so, on balance, this approach was appropriate. We also need to consider that children with various comorbidities and severely malnourished children were excluded. This produced appropriate study conditions; however, in a real-world setting where the intervention may be delivered as a blanket supplementary feeding programme to all, sicker children may not recover as readily as those featured in this study. Additionally, growth data were only measured at two time points, which prevents us from determining recovery trajectories over the study period. Nevertheless, the results remain compelling.