ROCKVILLE, MARYLAND. Mothers selectively transfer docosahexaenoic acid (DHA) to their fetus during pregnancy to support optimal neurological development. If the dietary intake of DHA is insufficient to meet the needs of both mother and fetus, then the needs of the fetus are met first. This may result in the mother becoming deficient and the subsequent development of major depression and other affective disorders. Dr. Joseph Hibbeln of the US National Institutes of Health report that the incidence of post-partum depression (PPD) is clearly linked to docosahexaenoic acid status and seafood consumption.
Dr. Hibbeln evaluated the results of 41 relevant studies involving over 14,000 women located in 23 different countries. He compared the incidence of post-partum depression in new mothers in each country with the average seafood consumption and average DHA concentration in the mothers’ milk in the country. The results were remarkable. Dr. Hibbeln found a clear correlation between the incidence of PPD and seafood consumption. The highest incidence of PPD (24.5%) was found in South Africa, which also reported the lowest seafood intake at 8.6 lb/person/year. In comparison, Japan reported a PPD incidence of only 2% and an average seafood consumption of 147.7 lb/person/year. In the United States average seafood intake amounted to 48.1 lb/person/year with a corresponding PPD incidence of 11.5%. Numbers for Canada were similar at 50.7 lb/person/year seafood consumption and 12.7% PPD.
Analyses of fatty acid content of mothers’ milk were available for 16 countries. While there was no correlation between PPD and the content of arachidonic acid and eicosapentaenoic acid, there was a clear correlation between PPD and low DHA level. South Africa reported the lowest docosahexaenoic acid content (0.15% of total fats in mothers’ milk) and the highest PPD incidence at 24.5%. The average DHA level in mothers’ milk in Japan was 0.81% versus a PPD incidence of 2%. Average docosahexaenoic acid level in the USA was 0.17% (PPD incidence of 11.5%).
Although there are clearly other factors predisposing to post-partum depression, Dr. Hibbeln found that the effects of low socioeconomic status, young maternal age, no partner, and poor education were minor when compared to the effect of seafood consumption and low DHA status. He points out that numerous studies have shown that docosahexaenoic acid status can be safely and effectively improved by supplementation with fish oil. Specifically, studies have found that supplementation with 1.1 gram/day of docosahexaenoic acid will increase breast milk concentration to 0.8% without any adverse effects. A level of 0.8% is equivalent to the average level observed in Japan and is associated with a low 2.0% risk of PPD.
Hibbeln, J. Seafood consumption, the DHA content of mothers’ milk and prevalence rates of postpartum depression: a cross-national, ecological analysis. Journal of Affective Disorders, Vol. 69, 2002, pp. 15-29