Postpartum depression, nutrition, and gut flora

In this blog, we’ll be discussing lesser-known facts about postpartum depression (PPD).

The first section will cover PPD risk factors, and then we’ll continue with nutritional strategies to prevent PPD.

The last section also contains clinician and patient resources for PPD.

Who is affected by postpartum depression?

The overall prevalence of postpartum depression is estimated to be 17% (95% CI:0.15–0.20) and has increased dramatically over the last decade (1).

According to data from Kaiser Permanente in Southern California, postpartum depression increased from 9.4% in 2010 to 19.3% in 2021, which is a relative increase of 109% (2).

Keep in mind that the actual prevalence of PPD may be underreported—it is not uncommon for women to keep quiet about their PPD symptoms, and it may go undiagnosed.

While anyone can develop PPD, women with a history of depression have a significantly higher likelihood of experiencing PPD.

To put this in perspective, in a study of 336,522 pregnancies, 5% of women with no history of depression developed PPD compared to 63% of women who reported depression before or during pregnancy (3).

An interesting note about this study is that the postpartum period was defined as two months or one year, giving insight into a more extended period that can be overlooked when it comes to PPD and other postpartum plights.

Basically, postpartum lasts much longer than the first few months after delivery, and many women face postpartum symptoms long after the newborn phase has passed.

For example, women with a history of depression had a 1.7-fold increase in PPD two months postpartum (adjusted OR: 1.7, CI: 1.61-1.79) and a 2.7-fold increase in PPD one year postpartum (adjusted OR: 2.70, CI: 2.61-2.79) (3).

Women who experience depression during pregnancy had the greatest odds of PPD—nearly 35 times the odds (adjusted OR: 34.64, CI:33.0-36.3) two months postpartum and 13 times the odds one year postpartum (adjusted OR: 13.1, CI: 12.6-13.6) (3).

Beyond a history of depression, a history of other psychiatric disorders was associated with a mildly increased risk of PPD, including panic disorder, bipolar disorder, PTSD, OCD, and eating disorders. After depression history, those with a history of anxiety had the greatest risk of PPD early postpartum and one year postpartum, with an odds ratio of 1.59 and 1.76, respectively (3).

In addition to mental health history, women with thyroid disorders may have a more considerable risk of PPD (4).

Bergink et al. (2011) observed that 19% of women with postpartum psychosis also had autoimmune thyroid disorder (AITD) in comparison to only 5% of matched healthy controls.

Additionally, women with postpartum psychosis and AITD were 67% more likely to later develop clinical thyroid failure, as opposed to 20% of controls with AITD (5).

Ethnicity and socioeconomic status impact the risk of postpartum depression

Black and Latina women are about 1.5-2 times as likely as White women to experience postpartum depression, and Asian and Pacific islanders are nearly three times as likely as white women to experience postpartum depression (6).

As previously mentioned, the rates of PPD have increased significantly over the last 11 years, and Black, Latina, and Asian/Pacific Islanders have experienced the most dramatic increase.

“From 2010 to 2021, the postpartum depression rate increased among Whites from 13.5% to 21.8%, a relative increase of 60% (95% confidence intervals [CI] 50-70%); among Hispanics, from 8.9% to 18.8%, 110% increase (95% CI: 100-120%), and among Blacks, from 9.2% to 22.0%; 140% increase (95% CI: 110-180%). Asian/Pacific Islanders had the largest relative increase (from 3.6% to 13.8%; 280% increase (95% CI: 220-350%)” (2).

Increased stress levels and adverse life events, including those related to racism, may increase the likelihood of postpartum depression (7, 8).

Vitamin D deficiency, which is more common in Black mothers, may be another contributing factor. Vitamin D is an essential nutrient for PPD prevention, as we will discuss later in this blog. As clinicians, we must understand all factors contributing to vitamin D deficiency in a specific population.

For example, for Black women, skin pigmentation plays a part in vitamin D synthesis, and there could be genetic reasons for vitamin D deficiency as well. There could also be less attention given to Black mothers to monitor vitamin D levels and provide appropriate supplementation to prevent deficiency.

Essentially, there isn’t just a vitamin D receptor (VDR) gene issue. There is also a difference in postpartum and prenatal care that can enhance underlying genetic differences.

Understanding risk factors for PPD is, of course, valuable. Still, I want to dig a little deeper down to the cellular level to understand the core dysfunctions at the heart of PPD and, more importantly, whether there are solutions.

Postpartum immune dysfunction, disruption in matrix metalloproteinases, blood-brain barrier integrity, and tumor necrosis factor may be implicated in postpartum depression (9).

A fascinating 2021 genome-wide study examined gene expression changes in women with PPD. What they found is remarkable.

“A total of 71 genes were significantly associated with depression scores at 2 months postpartum, after correction for multiple testing. The PPD-related genes were enriched for immune-related gene ontology biological processes, including humoral immune response and neutrophil-mediated immunity, and were overrepresented in the neutrophil degranulation and innate immune system pathways, suggesting a role of immune-pathway genes in PPD. These findings suggest that an altered immunological profile during pregnancy might play a role in PPD vulnerability” (10).

Interestingly, the genome study also uncovered a link between PPD and genes associated with estrogen sensitivity and signaling (10). The role of female hormones in PPD is recognized as a major factor in PPD incidence.

“During pregnancy, levels of progesterone are twenty times higher compared to non-pregnant women, and these levels remain increased throughout the gestational period. At the same time, oestradiol levels are two to three hundred times higher by the twentieth week of conception and they stay elevated throughout gestation. After childbirth, hormones drop significantly. The neurotransmitter activity that contributes to increased serotonin synthesis and decreased serotonin breakdown is effectively increased by oestrogen. Therefore, a sudden decrease in progesterone and oestrogen could lead to PPD by reducing serotonin levels” (11).

Do dietary factors make a difference in PPD?

Inadequate intake of calories, macronutrients, and micronutrients is the biggest and most common issue I see clinically in the postpartum population, particularly in those who are breastfeeding their babies.

The postpartum period, especially for lactating mothers, is a time that requires massive dietary intake, which many individuals and their healthcare practitioners underestimate.

Optimal caloric intake is essential for postpartum and lactating mothers in general, but those with a predisposition towards PPD, depression, and psychosis may be particularly susceptible to the harmful effects of undereating.

Beyond supporting optimal calorie intake, specific nutrients have been documented to protect against PPD.

Adequate intake of Vitamin D, EPA, DHA, and fiber (FOS, GOS) offers protective benefits against PPD (12).

Let’s take a closer look at each of these nutrients.

Vitamin D

A novel 2018 meta-analysis found that women with vitamin D levels of less than 50 nmol/l (20 ng/mL) had 2.67 times the risk of PPD. Furthermore, the lower the level, the more likely it is for a person to develop PPD (13).

The mechanisms behind the link between vitamin D insufficiency and PPD risk are not fully understood, but it may be related to the effect of vitamin D on the HPA-axis and regulation of inflammatory cytokines, as well as the vitamin’s impact on estradiol.

“One possible explanation is related to the location of VDRs within the brain. Actually, VDRs will be inadequately filled while one’s vitamin D concentration is in a deficient condition, interfering with the proper function of hormonal processes which could prevent mood disorders. In addition, following delivery and a sudden drop in estrogen, reducing maternal calcium deposits can affect gonadotropin-releasing hormone (GnRH) through the HPA axis, which played a role in the physiological regulation of neuronal activity and fertility cycle and has a role in low estrogen levels and postpartum depression” (13).

Vitamin D insufficiency is widespread among the general population.

Recent data has estimated that 47.9% of people have vitamin D levels lower than 50 nmol/L (14). Supplementing with vitamin D during pregnancy may be one strategy for preventing PPD (15, 16).

Omega-3 fatty acids

Women with perinatal depression (depression during pregnancy and postpartum) may have significantly lower levels of EPA and DHA and an elevated omega-6:omega-3 ratio (17). This observation aligns with studies showing that diets containing greater amounts of seafood may protect against PPD (18).

Omega 3 supplementation in forms that supply both EPA and DHA can help reduce postpartum depression, as several studies have shown over the years. A 2020 meta-analysis concluded that omega-3 supplementation is beneficial for managing PPD and should be considered as an adjunctive therapy for women struggling with PPD (19).

Omega-3 fatty acids are well known for their anti-inflammatory and anti-depressive actions. However, one of their lesser-known benefits is their interaction with gut microbiota, effectively enhancing bacterial diversity and balance (12).

Fiber

Fiber is a crucial and often overlooked nutrient. While all fiber, in general, has beneficial health effects, prebiotic fibers such as fructooligosaccharides (FOS) and galactooligosaccharides (GOS) are essential to consider for PPD due to the beneficial impact they have on specific gut bacteria.

Animal studies have shown us that prebiotic supplementation may be a therapeutic strategy for depression and postpartum depression (20, 21), an effect that is likely due to the modulation of beneficial gut bacteria.

While there are not yet studies on prebiotic supplementation and PPD, prebiotic supplementation is considered safe during pregnancy (22). I recommend it in my practice for women who struggle to get enough prebiotics from food alone.

It is important to note that people on low-carb diets (including carnivore and ketogenic diets, as well as those who are generally under-eating) are probably under-consuming prebiotic sources of fiber. Additionally, if someone is on a low-FODMAP diet, FOS and GOS will be restricted. The specific carbohydrate diet (SCD) is a therapeutic diet that allows some foods that are sources of FOS and GOS while limiting others.

Someone on a therapeutic diet for medical reasons should work with an experienced and detail-oriented nutrition professional who can analyze the dietary intakes of these nutrients, especially on a tool like Cronometer that looks up micronutrients. However, to my knowledge, there isn’t a tool that specifically calculates FOS and GOS.

Other nutrients to consider: Iron, copper, and zinc

Iron insufficiency affects the basal ganglia, the brain region that helps regulate emotional expression and recognition (12). Iron deficiency anemia has been linked to an increased risk of psychiatric disorders in the general population (23), and women with anemia during and after pregnancy have a significantly increased risk of PPD (24).

“Anemia during pregnancy and after pregnancy significantly increased the risk of postpartum depression. Hemoglobin decline may change the function of neurotransmitters and subsequently alter the cellular, oxidative and thyroid hormones metabolism. In addition, the reduction of inflammatory cytokines, such as interleukin 2, as causative agents for anemia, can be an influencing factor in depression. Therefore, anemia during pregnancy and after pregnancy may be one of the causes of depression by altering inflammatory cytokines” (24).

Iron deficiency OR surplus can contribute to gut bacteria dysbiosis (12); thus, iron supplementation must be approached with care.

Adequate, but not excessive, iron levels are essential to maintain microbial balance and reduce PPD risk. Taking targeted iron supplementation when needed while avoiding unnecessary supplementation can help reduce the risk of PPD.

Furthermore, looking at lab reports in the context of how markers change during the postpartum period is necessary because otherwise, the results can be misinterpreted.

Click here to learn more about the most accurate ways to interpret blood tests during pregnancy.

Excess copper or imbalances between zinc and copper may increase the risk of postpartum depression.

Copper rises significantly in pregnancy, and this is normal. However, poor detoxification of copper, poor detoxification in general, and poor liver function can cause copper to stay elevated after birth.

Excess copper, especially unbound copper, that is, copper that is not bound to ceruloplasmin, can cause anxiety and postpartum depression, and many studies found that the copper-to-zinc ratios are much higher in postpartum depression (25).

A high copper-to-zinc ratio could be due to insufficient zinc levels, an absolute high copper level, or a relative excess of copper compared to zinc.

Poor digestion and diets low in zinc, such as diets low in animal foods, may increase the risk of high copper relative to zinc. Additionally, some diets may be quite high in copper, such as those rich in beef and pork liver and diets very high in nuts. Be aware if your patient is frequently using nut-based flour substitutes such as almond or hazelnut flour.

In addition to targeted nutrition, it is crucial to consider the diet as a whole. As they say, you can’t out-supplement a poor diet, an adage particularly relevant during pregnancy and postpartum.

For instance, the consumption of ultra-processed foods and artificial sweeteners has been linked to an increased risk of depression in women (26).

Some examples of ultra-processed foods include packaged sweetened breakfast cereals, packaged snack foods, soft drinks, packaged sliced bread, potato flakes, boxed macaroni and cheese products, boxed mashed potato powder/flakes, candy bars, etc. Artificial sweeteners include sucralose (Splenda), acesulfame potassium (Ace-K), aspartame (Equal/Nutrasweet), and saccharin (Sweet N’ Low).

While the study above isn’t specifically on postpartum depression, it makes sense for postpartum mothers to avoid ultra-processed foods not only due to the increased depression risk but also because of their low nutrient value.

Another study looking at dietary patterns and postpartum depression found a link between low intake of vegetables and low dietary diversity (according to the study data, low diversity meant low intake of vegetables, fruit, dairy, and fish and shrimp) and increased PPD (27).

Of course, we must acknowledge the possibility that the women included in this study had less motivation to consume a variety of foods due to their depressive symptoms, and this influenced the observational findings.

Still, it is abundantly clear that nutritional factors have a significant impact on PPD, for the reasons discussed above, as well as the impact of diet and specific nutrients on gut flora.

Diets higher in ultra-processed food and lacking in a variety of nutrient-rich foods and fiber contribute to gut dysbiosis and have been implicated in mood disorders due to their effect on the gut-brain axis, the bidirectional relationship between the gut and brain (28).

Gut flora and postpartum depression

The human gut flora is foundational to health and disease. Research is continuing to show just how integral gut microbiota is to the homeostasis of all body systems, including mental health, hormonal health, and the nervous system.

Diet is integral in shaping gut flora and maintaining balance within the gut ecosystem. All the nutrients discussed above play a part in maintaining a healthy gut.

Gut flora impacts the regulation of the HPA axis and may profoundly affect mood and mental health.

Research on the gut-brain axis suggests that gut dysbiosis may be implicated in the onset of major depressive disorder and affect symptom severity (29).

Probiotic supplementation is becoming increasingly suggested as a potential therapeutic strategy for depression and may also be beneficial for PPD.

There has been some research on targeted probiotic supplementation as a way to support women struggling with postpartum depression and anxiety.

In particular, Lactobacillus rhamnosus HN001 performed well in a randomized, double-blind, placebo-controlled trial. In this trial, pregnant women took an L. rhamnosus HN001 probiotic from 14-16 gestation until six months postpartum.

“Mothers in the probiotic treatment group reported significantly lower depression scores … and anxiety scores … than those in the placebo group. Rates of clinically relevant anxiety on screening score … were significantly lower in the HN001 treated mothers” (30).

Lactobacillus rhamnosus HN001 is found in many probiotic formulations, including:

Metagenics Ultra Flora Acute Care
Now Foods Women’s Probiotics
Xymogen ProBio Max
Genestra HMF Multi Strain
Master Supplements Theralac Pro
Pharmax HLC Multi Strain

I gathered the information on probiotics from ProbioticAdvisor.com, which is an invaluable resource for clinicians who utilize probiotics in their practice.

Emotional health and postpartum depression

Finally, emotional health affects susceptibility to postpartum depression, anxiety, and psychosis.

Thus, ensuring that people in a place of emotional turmoil are getting the support and resources they need is of the utmost importance to our patients and can help prevent many of these adverse conditions.

Below are resources for learning and support for postpartum depression and anxiety:

Support for PPD

The Postpartum Stress Center

Homeopathy for PPD

PPD and serum trace elements

“Structural racism and pandemic stressors associated with postpartum depression and anxiety among Black individuals, study finds”

Office on Women’s Health: PPD resources

American Psychological Association: PPD

American Psychiatric Association: What is peripartum depression?

References