The Relationship Between Vitamin D, Breastfeeding Status, and Postpartum Depression
by Anne Eglash MD, IBCLC, FABM
Depression is twice as common among women as compared to men partially because of women’s risk of peripartum depression. Vitamin D has been extensively studied for its positive effects on mental health, though the exact mechanisms remain unclear. Evidence suggests that vitamin D directly impacts serotonin synthesis, like how SSRI antidepressants work.
Vitamin D is primarily acquired through sun exposure and, to a lesser extent, through diet. Women of childbearing age are particularly at risk of vitamin D insufficiency, making supplementation during pregnancy and lactation advisable to ensure adequate intake.
This week’s study investigated the association between serum vitamin D concentration with depression symptoms, focusing on pregnant and postpartum women. The authors analyzed data from the 2007-2018 US National Health and Nutrition Examination Survey (NHANES), which randomly selects participants based on US Census data. They identified 11,337 participants aged 20-44 at the time of the survey, including 449 postpartum (162 breastfeeding, 287 not breastfeeding) and 287 pregnant. The study did not specify breastfeeding intensity, such as exclusive or mixed feeding.
The findings indicated a negative correlation between higher vitamin D levels and depression symptoms across all subpopulations.
What else? See the question!
- Vitamin D concentration had the most significant impact on moderate to severe depression in pregnant women compared to non-pregnant and postpartum women.
- Among women who were less than 12 months postpartum, those who were breastfeeding had a lower incidence of depression compared to nonlactating women.
- Among postpartum women, vitamin D concentration was more impactful on moderate to severe depression in breastfeeding women compared to non-breastfeeding women.
See the Answer
Abstract
The objective was to investigate associations of serum vitamin D concentration with depressive symptoms and assess the impact that vitamin D concentration has on the occurrence of depressive symptoms in 20–44-year-old pregnant women, postpartum women, non-pp women (non-pregnant/postpartum women), and men, including a separate subgroup analysis of postpartum breastfeeding and non-breastfeeding women. The study populations were selected from the 2007–2018 NHANES public data. Subjective interview data and objective laboratory data including depressive symptoms, serum vitamin D concentration, nutrient intake, and demographic information were utilized. Two diet patterns were created using principal component analysis, and a Bayesian multinomial model was fit to predict the depression outcomes for each subpopulation. The estimates for the log vitamin D slope parameter were negative for all cohorts; as vitamin D increased, the probability of having no depression increased, while the probability of depression decreased. The pregnant cohort had the steepest vitamin D slope, followed by postpartum women, then non-pp women and men. Higher vitamin D concentration had more impact on decreasing depression risk in pregnant and postpartum women compared to non-pp women and men. Among postpartum women, higher vitamin D concentration had a greater influence on decreasing breastfeeding women’s depression risk than non-breastfeeding women.
This study demonstrated that higher vitamin D levels are more likely to reduce the risk of moderate or severe depression during pregnancy and lactation as compared to their impact on men or non-pregnant, non-postpartum women. Lactating women, in particular, were found to benefit more from higher vitamin D levels than non-breastfeeding postpartum women.
While this study demonstrates a clear correlation between vitamin D status and major depression, it does not measure whether vitamin D supplementation during pregnancy or lactation can prevent peripartum lactation.
Regardless, this research should compel healthcare providers to advise vitamin D supplementation during pregnancy and postpartum for both the mother and infant. For women experiencing postpartum depression, checking a vitamin D level is warranted to ensure that the mother is replete as part of the evaluation and treatment for depression.