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).
Where will all this brain fuel come from? As always, the heat’s on you to keep those supplies coming through your Pregnancy Diet. But a DHA-heavy diet can be a little tricky to follow, since so many fish are off-limits when you’re expecting (get the whole story on eating fish during pregnancy). Luckily, DHA is found in safe-to-savor coldwater, fatty fishes such as salmon (always choose wild when you can), cod, and fresh tuna.
Haven’t found your sea legs? Try DHA-rich eggs, sometimes called omega-3 eggs. They’re laid by chickens on a DHA-supplemented diet - it’ll say so on the package. Regular egg yolks contain a small amount of DHA, too. Vegans, fear not - algae is an all-natural plant source of DHA, so you can incorporate foods like seaweed into your diet.
These foods also contain a concentrated amount of DHA:
Anchovies
Herring
Sardines
Trout
Other oily fishes
Smaller, but still significant, amounts of DHA are in these foods:
Canned tuna (which you can safely eat six ounces of each week)
Crab
Shrimp
An editorial published in response to the study stated potential reasons why this outcome occurred – these comments also shed light on why there seem to be discrepancies in the medical literature on this subject. One possibility is that the criteria used to measure infant brain development in this study were not sufficiently sensitive to detect small but important differences in cognition in 18-month olds. The criteria used were based on global measures of cognition, and are not designed to detect differences in specific processes such as memory, attention, and problem-solving.[7] As mentioned above, previous studies have seen differences in problem solving in infants given supplemental DHA.[5] Furthermore, there are several cognitive functions that cannot be accurately measured until children reach preschool and school age – the editorial cites a smaller study of fish oil supplementation during pregnancy that found enhanced IQ scores in 4 year olds.[9] I agree that it isn’t possibly to reliably measure intelligence in an 18-month old, and that better results would come from studies that measure cognitive function once the children are in school.
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References:
1. Yurko-Mauro, K., Cognitive and cardiovascular benefits of docosahexaenoic acid in aging and cognitive decline. Curr Alzheimer Res, 2010. 7(3): p. 190-6.
2. Muskiet, F.A., et al., Is docosahexaenoic acid (DHA) essential? Lessons from DHA status regulation, our ancient diet, epidemiology and randomized controlled trials. J Nutr, 2004. 134(1): p. 183-6.
3. Ryan, A.S., et al., Effects of long-chain polyunsaturated fatty acid supplementation on neurodevelopment in childhood: a review of human studies. Prostaglandins Leukot Essent Fatty Acids, 2010. 82(4-6): p. 305-14.
4. Koletzko, B., I. Cetin, and J.T. Brenna, Dietary fat intakes for pregnant and lactating women. Br J Nutr, 2007. 98(5): p. 873-7.
5. Drover, J., et al., Three randomized controlled trials of early long-chain polyunsaturated Fatty Acid supplementation on means-end problem solving in 9-month-olds. Child Dev, 2009. 80(5): p. 1376-84.
6. Makrides, M., et al., Effect of DHA supplementation during pregnancy on maternal depression and neurodevelopment of young children: a randomized controlled trial. JAMA, 2010. 304(15): p. 1675-83.
7. Oken, E. and M.B. Belfort, Fish, fish oil, and pregnancy. JAMA, 2010. 304(15): p. 1717-8.
8. Martins, J.G., EPA but not DHA appears to be responsible for the efficacy of omega-3 long chain polyunsaturated fatty acid supplementation in depression: evidence from a meta-analysis of randomized controlled trials. J Am Coll Nutr, 2009. 28(5): p. 525-42.
9. Helland, I.B., et al., Maternal supplementation with very-long-chain n-3 fatty acids during pregnancy and lactation augments children’s IQ at 4 years of age. Pediatrics, 2003. 111(1): p. e39-44.
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