Does omega-3 supplementation during pregnancy prevent postpartum depression?

Omega-3 fats are essential – we must take them in from our diets because our body cannot synthesize them. These fats are extremely important for many facets of our health, especially the health of the brain and cardiovascular system.[1] Omega-3 fat is a major structural component of brain cell membranes and the retina – about 60% of the dry weight of the brain is made up of fat, and DHA is the most abundant fat in the brain. [2]

As such, DHA is an essential factor in early brain development, and maintaining adequate levels during pregnancy is believed to benefit the child’s cognitive development.[3] The current consensus is that pregnant women should consume at least 200 mg DHA each day to promote normal fetal brain development. Pregnant women are also urged to limit fish consumption because of mercury contamination, which is harmful to the brain of the developing baby.[4] Fish oil or vegan DHA supplements are therefore an attractive option for pregnant women.

In 2009, the results of three randomized controlled trials were pooled and showed that babies given supplemental DHA in formula scored higher on a problem solving test at 9 months of age than babies given control formula. However, there is some disagreement in the literature as to whether DHA supplementation during pregnancy and infancy actually improves cognitive development in the child.[5]

A recently published study in the Journal of the American Medical Association reported an unexpected finding: Pregnant women who took fish oil capsules (800 mg DHA and 100 mg EPA per day) compared to vegetable oil placebo capsules did not have lower incidence of postpartum depression, and their children did not have improved cognitive development at 18 months of age.[6]

Of course, this does not mean that pregnant women shouldn’t bother taking DHA. The developing baby’s only source of DHA for beginning to build its brain tissue is its mother’s dietary intake. DHA supplementation also reduces the risk of preterm birth – a factor known to be associated with compromised cognitive development in the infant and maternal depression.[7]

In reference to the lack of effect on symptoms of depression, the therapeutic effects of omega-3 supplements on depression are due mostly to EPA rather than DHA, according to a recent meta-analysis. [8] I recommend omega-3 supplementation including 1,000 mg of EPA to treat depression – the relatively low dose of EPA used in this trial may therefore be responsible for the lack of effect on depression in this study.

The most fabulous of fats? The omega-3 polyunsaturated fatty acids, most notably DHA (known in scientific circles as docosahexaenoic acid). While omega-3s are healthy additions to any diet (they lower cholesterol and blood pressure, reducing the risk of heart disease), they're particularly smart selections when you're building a baby. DHA, for instance, is a vital ingredient in brain and retinal tissue, so it's essential for proper brain growth and eye development in fetuses and young babies. During the third trimester, brain growth is at its peak — and it continues to grow during the first year of life, tripling in size by the time your baby is a year old. This means that your baby's need for this must-have nutrient will skyrocket (the brain's DHA content must multiply by three to five times during these busy three months).