Cognitive Tests and Major Cognitive Outcomes

Cognitive Tests

• A variety of standardized cognitive tests were used to assess outcomes in multiple cognitive domains.
• These cognitive domains included:
  • Learning abilities
  • Verbal reasoning
  • Intellectual functioning
  • Information processing speed
  • Vocabulary
  • Word reasoning
  • Speed and accuracy of discrimination
  • Fine and gross motor skills
  • Coding
  • Symbol search
  • Working memory
• Specific tests:
  • Wechsler Pre-school and Primary Scale of Intelligence (WPPSI) was administered in half of the studies [55 56 57 60 61 63 ].
  • 9-Hole Peg Test (9-HPT) was administered in two experimental studies [56 B.57 ].
  • Mullen Scale of Early Learning (MSEL) was administered in two studies [59, 62 B].
• Table 2 provides details on:
  • Cognitive tests used in each trial
  • Cognitive domains assessed
  • Effects on cognitive outcomes of preschool-aged children

Major Cognitive Outcomes

Single Nutrient Supplementation

• Five RCTs measured the effect of supplement-based interventions on children's cognition.
• Three trials found no significant impact on cognition with:
  • B vitamin supplementation [55]
  • Iodized salt supplementation [59]
  • Guava supplementation [62]
• Guava Supplementation Details:
  • Guava is rich in vitamins, minerals, and lycopene (a carotenoid phytonutrient with antioxidant effects) [67].
  • It was used to facilitate nonheme iron absorption [68].
  • Guava supplementation improved iron status but had no significant effect on cognitive function [68 B].
• Trials that found significant results:
  • Iron intervention [58]:
    • For children with iron deficiency anemia, iron supplementation increased accuracy and the speed of discrimination on the continuous performance task.
    • For children with adequate iron status at baseline, iron supplementation did not affect performance on the continuous processing task.
  • DHA supplementation intervention [59]:
    • No significant differences in cognitive function scores between the intervention and placebo groups.
    • Higher blood DHA levels were significantly associated with higher scores on the Peabody Picture Vocabulary Test (measures listening comprehension and vocabulary).

Multiple-Micronutrient Supplementation

• Three RCTs measured the impact of multiple-micronutrient food fortification on children's cognitive development.
• 11-week intervention [64]:
  • Consisted of eight grams of a point of use multiple micronutrient powder added to maize-meal porridge at breakfast for children 36-79 months of age.
  • Children in the intervention group significantly increased their scores on the simultaneous scale and the non-verbal index of the Kaufman Assessment Battery for Children compared to the control group.
• Longer trial with somewhat younger children [65]:
  • The cognitive benefits of a point of use multiple micronutrient powder were dependent upon whether the child was attending a low-quality or a high-quality preschool.
  • The quality of preschools was assessed.