MAASTRICHT, THE NETHERLANDS. Docosahexaenoic acid (DHA), an omega-3 fatty acid and main component of fish oil, is an extremely important nutrient in the development of the brain of the fetus and infant. It is therefore not surprising that nature has ordained that blood plasma and red blood cell (erythrocyte) levels of DHA increase during pregnancy, possibly due to an enhanced conversion of docosapentaenoic acid to DHA. What is not known is how long it takes for omega-3 fatty acid DHA concentrations to return to pre-pregnancy levels, and whether the change is different in breastfeeding women than in those who feed their infants formula. Researchers at Maastricht University provide an answer to these questions.
Their study involved 57 healthy women (average age of 30 years) who were recruited into the study after 36-37 weeks of pregnancy. The women gave birth after an average 40 week of pregnancy and were than followed for 64 weeks post-partum. Twenty-two of the women exclusively bottle-fed their infants, while the remaining 35 breastfed. The fatty acid composition of plasma and erythrocytes was analyzed at entry to the study and then at regular intervals post-partum. Dietary intakes of fatty acids were assessed 4 and 32 weeks post-partum via validated food frequency questionnaires.
The researchers found that the total fatty acid content of plasma and erythrocytes decreased significantly post-partum, while the percentages of essential fatty acids increased with the exception of DHA. DHA decreased steadily post-partum in both lactating and non-lactating women, but the decrease was substantially greater in breastfeeding mothers. The average daily intake of DHA at 32 weeks post-partum was 55 mg/day in non-lactating women and 81 mg/day in lactating women. However, it is estimated that the daily transfer of DHA in breast milk is about 51 mg, thus leaving only 30 mg/day for the breastfeeding women, likely not enough to cover their basic needs for this omega-3 fatty acid.
Otto, SJ, et al. Comparison of the peripartum and postpartum phospholipid polyunsaturated fatty acid profiles of lactating and nonlactating women. American Journal of Clinical Nutrition, Vol. 73, June 2001, pp. 1074-79