Women are strongly encouraged to take prenatal vitamins, and there is significant data to indicate multiple benefits to the child, including decreased risk of various congenital defects and certain types of childhood cancers.  Less understood is the impact of these supplements on the mother’s mental status and her risk for mood disorder during the perinatal period.  A group of researchers from Alberta, Canada has recently examined the risk for postpartum depressive symptoms in women enrolled in the Alberta Pregnancy Outcomes and Nutrition (APrON) study, specifically examining the nutrients ingested through supplements to determine whether any individual supplementary nutrients may modulate the risk of postpartum depressive symptoms.

In this study, 475 women completed the Edinburgh Postnatal Depression Scale (EPDS) at least twice in pregnancy and at 12 weeks postpartum.  59 (12%) scored greater than or equal to 10 on the EPDS, where a score of greater than or equal to 10 is considered to be “at least probable minor depression”.  Almost all of the women (99%) took some type of micronutrient supplement during the prenatal period.

It was observed that mean nutrient intakes from supplements were higher in women with lower EPDS scores.  Looking at individual nutrients, the researchers noted that the mean intake of selenium and omega-3 differed significantly (p = 0.0015 and 0.01, respectively) between women with EPDS <10 and those with EPDS greater than or equal to 10.

This isn’t the first time we have heard about a link between selenium and PPD.  A while back there was an article published regarding the use of selenium and risk of PPD.  A randomized trial from Mokhber and colleagues reported significantly lower EPDS scores in a group of pregnant Iranian women taking selenium supplements compared to a comparison group after controlling for sociodemographic and medical history variables.

The authors of the current article also comment on another study from Pasco and colleagues which found that low intake of selenium (<8.9 µg/day) in non-pregnant adult women was associated with almost a three-fold increase in the likelihood of major depressive disorder (OR 2.95, 95%CI 1.00-8.72) after adjusting for age and socio-economic status.

The Recommended Dietary Allowance (RDA) of selenium for adult women is 55 mcg. The RDA is 60 mcg for pregnant and 70 mcg for lactating women. Most of our dietary selenium comes from plant foods, and in the United States selenium deficiency is very rare.  Doing a quick internet search, I discovered that many popularly used prenatal vitamins do not contain selenium.

So what’s so special about selenium?  Selenium is incorporated into proteins to make selenoproteins, which are important antioxidant enzymes and help prevent cellular damage from free radicals.  Other selenium-containing proteins help regulate thyroid function and play a role in the functioning of the immune system. Exactly how selenium may modulate risk for mood disorders is not understood.

The findings regarding selenium are interesting; however, in this type of naturalistic study, supplementation with selenium may be a proxy for some other behavior that reduces the risk of perinatal depression.  The authors emphasize that multiple factors contribute to risk for postpartum depression and comment on various factors, including depression during pregnancy, recent stressful life events, and lack of social supports, which are strongly associated with increased risk of postpartum depression.

Ruta Nonacs, MD PhD

Leung B, et al. Prenatal micronutrient supplementation and postpartum depressive symptoms in a pregnancy cohort. BMC Pregnancy and Childbirth. 2013 Jan;13:2. DOI: 10.1186/1471-2393-13-2.

Mokhber N, et al. Effect of supplementation with selenium on postpartum depression: a randomized double-blind placebo-controlled trial. J Matern Fetal Neonatal Med. 2011 Jan;24(1):104–108. DOI: 10.3109/14767058.2010.482598.

Pasco JA, et al.  Dietary selenium and major depression: a nested case–control study. Complement Ther Med. 2012 Jun;20(3):119–123. DOI: 10.1016/j.ctim.2011.12.008.

Read more about selenium from the NIH Office of Dietary Supplements