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DHA Improves Motor Milestones

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Study Finds DHA Supplementation of Healthy Infants Improves Some, But Not All Motor Milestones

A study in the January edition of the American Journal of Clinical Nutrition by Agostoni et al. found that docosahexaenoic acid (DHA) supplementation improved the time to achieve some, but not all motor development milestones in term infants.  At the beginning of the study, exclusive or predominant breastfeeding was reported by approximately 95% of mothers.  At hospital discharge, term infants were randomly assigned to receive 1 mL orally of either a liquid study preparation known as the “intervention” (400 IU vitamin D3 + 20 mg DHA) or placebo (400 IU vitamin D3) one time per day through the first year of life.  (Vitamin D3 was given to the infants to improve maternal compliance with the prescribed supplementations and was dosed at the level recommended by the Italian Recommended Dietary Allowance for age.)  Postpartum, mothers were presented with a form containing instructions and pictures of infant motor skills to observe; they used the form to record the first date their infant achieved a World Health Organization (WHO) milestone, as described on the form and a physician confirmed the infants development at age 12, 32, and 52 weeks.  Infants fed DHA reportedly showed a significantly shorter time to achieve the milestone of sitting without support, as well as a significantly shorter time to achieve the early fine motor milestones of “reaching an object to touch” and “bringing toy to mouth.”  Additionally, infants supplemented with DHA showed an earlier language milestone, saying the first comprehensible word composed of > 2 syllables sooner than unsupplemented infants.  No significant differences were observed between the two groups for the gross motor developmental milestones of hands-and-knees crawling, standing alone, and walking alone.  The authors state, however, that the long-term clinical significance of the difference in sitting without support between the two groups “remains unknown.”

Strengths of this study include its large sample size, its double-blindedness, and the use of a placebo control.  Limitations include the parental evaluation of an infants’ milestone achievement (although this has been previously validated2) and the lack of direct measurement of blood DHA concentrations. 

This new work adds to the growing body of controversial findings in the literature on the effect of DHA supplementation in infants.  Several studies have examined the role of DHA on gross motor development and had found differing results.  Makrides et al. found that the Bayley Psychomotor Developmental Index did not differ between DHA supplemented and unsupplemented breastfed infants3 and Birch et al. found in a randomized trial that dietary DHA supplied through formula failed to show a significant effect on Psychomotor Developmental Index scores at 18 months.4  On the other hand, Bouwstra et al. in different studies found that DHA supplementation of term infants was associated with a positive effect on the quality of infant movement and neurologic conditions of infants at 18 months.5-6  As other studies suggest that the ability to synthesize DHA from alpha-linolenic acid may be increased after the first seven months of life,7 the timing of dietary supplementation could explain some of the variability in effects of DHA supplementation in infants. 

Given the significance of the differences in several assessed motor milestones, the authors conclusion that “no demonstrable persistent effects of DHA supplementation on later motor developmental milestones were observed” is questioned.

References Cited:

  1. Agostoni, C., et al., Docosahexaenoic acid supplementation and time at achievement of gross motor milestones in healthy infants: a randomized, prospective, double-blind, placebo-controlled trial. Am J Clin Nutr, 2009. 89(1): p. 64-70.

  2. Knobloch, H., et al., The validity of parental reporting of infant development. Pediatrics, 1979. 63(6): p. 872-8.

  3. Makrides, M., et al., A critical appraisal of the role of dietary long-chain polyunsaturated fatty acids on neural indices of term infants: a randomized, controlled trial. Pediatrics, 2000. 105(1 Pt 1): p. 32-8.

  4. Birch, E.E., et al., A randomized controlled trial of early dietary supply of long-chain polyunsaturated fatty acids and mental development in term infants. Dev Med Child Neurol, 2000. 42(3): p. 174-81.

  5. Bouwstra, H., et al., Long-chain polyunsaturated fatty acids have a positive effect on the quality of general movements of healthy term infants. Am J Clin Nutr, 2003. 78(2): p. 313-8.

  6. Bouwstra, H., et al., Neurologic condition of healthy term infants at 18 months: positive association with venous umbilical DHA status and negative association with umbilical trans-fatty acids. Pediatr Res, 2006. 60(3): p. 334-9.

  7. Carnielli, V.P., et al., Synthesis of long-chain polyunsaturated fatty acids in preterm newborns fed formula with long-chain polyunsaturated fatty acids. Am J Clin Nutr, 2007. 86(5): p. 1323-30.