Pregnancy and early childhood are periods of human development when the body has an increased requirement for micronutrients (vitamins and minerals). Animal studies have shown the importance of preconception nutrition for offspring development; however, long-term human trials are lacking. Investigators aimed to determine the long-term effects of preconception micronutrient supplementation on children’s intellectual functioning.

Several micronutrients play critical roles in fetal development. For example, folic acid supplementation during pregnancy prevents neural tube defects, and iron plays an important role in brain maturation, promoting cell division, myelination, and synaptic development. Less is known about the importance of other micronutrients, however.

The researchers assigned over 5,000 female participants to take folic acid (2,800 micrograms) only, iron plus folic acid (60 milligrams iron and 2800 micrograms folic acid), or multiple micronutrients (15 micronutrients including iron and folic acid) for an average of 33 weeks between baseline and conception. Researchers tracked 1,300 of the participants' children from birth to the age of six. They tested the children on multiple domains of intelligence and collected information regarding maternal health and home life.

Compared to children whose mothers received only folic acid, children in the iron plus folic acid and mixed micronutrient group performed better in multiple domains, including verbal comprehension, perceptual reasoning, working memory, and processing speed. This effect was strongest for children whose mothers consumed the supplements for greater than 26 weeks before conception. The effects of supplementation were also stronger for children born to households with low socioeconomic status.

The authors concluded that preconception micronutrient supplementation is important to optimize child development and recommended the promotion of supplementation to all females of child-bearing age.

• Link to full report.