Postpartum blues are a common and healthy form of grief that tends to peak five days after giving birth. But those blues are also a high-risk condition for postpartum depression, the most common complication of having children in the US. A recent article in PNAS shows that nutritional supplements intended to counteract physiological changes that occur after childbirth are effective in reducing the grief associated with postpartum blues. This dietary supplement reduced postpartum sadness and effectively reduced the risk of postpartum depression.
For psychiatrists, postpartum blues is considered the “prodrome” for postpartum depression. That means increased postpartum blues signal the likely onset of postpartum depression. If the severity of the postpartum blues could be reduced, the chances of developing depression should also be reduced.
Postpartum blues are thought to be caused by hormonal changes. After giving birth, women experience severe drops in estrogen and progesterone levels, and these drops are thought to be related to depressive symptoms. Postpartum depression is also associated with changes in brain chemicals, including an increase in the enzyme monoamine oxidase A (MAO-A), which helps the brain regulate neurotransmitter activity.
For the study of PNAS, the researchers gave women a dietary supplement containing L-tryptophan, L-tyrosine, blueberry juice and blueberry extract. This supplement was chosen because L-tryptophan and L-tyrosine are believed to help you fall asleep, balance post-pregnancy MAO-A activity, and reduce oxidative stress. The additions of blueberries have been added to increase the palatability of the supplement and because research on blueberry extract has shown that it can help chemicals cross the blood-brain barrier.
A group of 20 women received this supplement and their mood was compared to 21 control women who did not receive it.
The mood in the control group was significantly lower than in the group receiving the supplement. So was the Visual Analog Scale, a commonly used measure of pain. The scores of controls were almost a thousand times higher than those of women who received the supplements. On the profile of mood states, another commonly used depression assessment, the control group experienced a significant increase in depressive symptoms, while the women who received the dietary supplement showed a decrease in depressive symptoms.
Although this trial was small, it had an effect size of 2.9. This means a threefold improvement in mood, which is quite significant. However, this was not a randomized controlled trial, so the subjects and investigators were not blinded to their treatment conditions. This means that the placebo effect may have influenced the differences between the two groups.
While this finding is compelling, a randomized controlled trial of this treatment is needed before we can be more confident in the effects of the dietary supplement. But the supplement does not seem to have any negative effects. Therefore, there is no reason not to proceed with tests that are more robust, with larger samples, randomization to treatment or control conditions, and blinded investigators. With a more complete study of this type of supplement, its true therapeutic potential should be clearer.
PNAS2017. DOI: 10.1073/pnas.1611965114 (About DOIs)