Dietary Intake of DHA during Pregnancy in Canada May Pose Risk to Infants
Innis SM & Friesen RW. American Journal of Clinical Nutrition. 87:548-557, (2008).
Nutrition Research Program, Child and Family Research Institute, Department of Pediatrics, University of British Columbia, Vancouver, BC.
This present study was designed to determine whether the DHA (docosahexaenoic acid) intake/status would be so low among some pregnant women (in Vancouver, B.C. and surrounding area) so as to pose a risk for impaired infant development of the central nervous system. Healthy pregnant women were randomly assigned to receive a vegetable oil placebo (lacking DHA) or 400 mg/day of DHA via algal oil supplementation from 16 weeks of gestation until delivery of their infant. Arterial venous blood was also collected for assessment of omega-3 status including DHA in the circulating red blood cells. Visual acuity was determined at 60 days after birth in the infants by using the Teller Acuity Card Procedure at a test distance of 38 cm. A total of 135 women (67 in the placebo group and 68 in the DHA group) completed the study. The overall results indicated that more infants of women following their normal diet had lower visual acuities as compared to infants of mothers in the DHA intervention group. The authors conclude that the low dietary intakes of DHA omega-3 fatty acids offer supporting evidence that current dietary practices place women at risk of inadequate DHA status during pregnancy. They also point out that the present study does not specifically address the issue of DHA omega-3 fatty acid requirements which would require functional assessment to determine the intakes above which no further benefit occurs regardless of increasing DHA status. The authors emphasize the need for further studies to address dietary omega-3 fatty acid requirements (particularly DHA) for pregnancy and lactation.
Dr. Holub's Comments:
This important study has far-reaching implications with respect to the introduction in North America and elsewhere of official DRI values for DHA omega-3 consumption during pregnancy, lactation, infancy, and possibly other stages in the lifespan. Furthermore, this paper should further stimulate consideration towards the establishment of set targets for DHA intakes (mg/day) at different stages in life. The level of supplementation along with DHA supplementation used in the present study (400 mg/day) is approximately 5 times greater than the current average intake in pregnant women as studied in central Canada by direct assessment methodology (Denomme et al. Journal of Nutrition. 135: 206-211, 2005).