Can Prebiotic Supplements Help Improve Depression Symptoms in Women with Obesity?

What you need to know

• This study examined whether taking a prebiotic supplement (inulin) along with following a calorie-restricted diet could help improve depression symptoms and reduce inflammation in women with obesity and major depressive disorder.

• After 8 weeks, there were no significant differences in depression scores, inflammatory markers, or other outcomes between the group taking inulin and the placebo group.

• Both groups showed some improvements in weight and depression scores, likely due to the calorie-restricted diet that all participants followed.

The Link Between Depression, Obesity, and Inflammation

Major depressive disorder (MDD) is one of the most common mental health conditions worldwide, affecting hundreds of millions of people. Women tend to be more affected by depression than men. There appears to be a two-way relationship between depression and obesity - people with depression are more likely to become obese, and those with obesity are at higher risk of developing depression.

Researchers now consider depression to be an inflammatory condition. Some of the known risk factors for depression, like chronic stress, lack of physical activity, and obesity, are associated with chronic low-grade inflammation in the body. Recent studies have also found that imbalances in gut bacteria and increased intestinal permeability (sometimes called “leaky gut”) may play a role in depression by disrupting the immune system.

When the intestinal barrier becomes more permeable, it allows bacterial components like lipopolysaccharide (LPS) to enter the bloodstream more easily. This can trigger inflammation throughout the body. Higher levels of inflammatory molecules have been found in both obesity and depression compared to healthy individuals.

Potential Benefits of Prebiotics

Given the links between gut health, inflammation, and depression, researchers have been exploring whether prebiotics could help improve symptoms in people with depression and obesity. Prebiotics are types of dietary fiber that feed beneficial gut bacteria. Some studies have found that prebiotics can help restore a healthier balance of gut bacteria, improve the intestinal barrier, and reduce inflammation.

A few previous studies have shown promising effects of prebiotic supplements on mood and depression symptoms. However, the results have been mixed overall, and more research is needed, especially in people with both obesity and clinical depression.

About This Study

This clinical trial aimed to investigate whether taking a prebiotic supplement (inulin) along with following a calorie-restricted diet could help improve depression, inflammatory markers, and other outcomes in women with obesity and MDD. The researchers were interested in several key measures:

• Depression symptoms
• Anxiety
• Overall well-being
• Body weight
• Markers of intestinal permeability (zonulin)
• Markers of bacterial endotoxins in the blood (LPS)
• Inflammatory molecules (e.g. TNF-alpha, IL-10)
• Brain-derived neurotrophic factor (BDNF) - a protein important for brain health

How the Study Worked

The study included 45 women between ages 20-50 who had:

• Obesity (BMI 30-40)
• Major depressive disorder (mild to moderate severity)
• Been taking antidepressant medication for at least 6 months

The women were randomly assigned to one of two groups:

1. Prebiotic group: 10 grams of inulin powder per day
2. Placebo group: 10 grams of maltodextrin powder per day

All participants followed a calorie-restricted diet plan designed to produce weight loss. The study lasted for 8 weeks.

Before and after the 8-week period, the researchers measured:

• Body weight
• Depression symptoms using multiple questionnaires
• Anxiety symptoms
• Overall well-being
• Blood levels of inflammatory markers, LPS, zonulin, and BDNF

Key Findings

After 8 weeks, the researchers found:

• Both groups lost a similar amount of weight
• Depression scores improved to a similar degree in both groups
• There were no significant differences between the two groups in anxiety, well-being, or any of the blood markers measured

In other words, taking the prebiotic supplement did not lead to any additional benefits beyond the effects of the calorie-restricted diet alone.

Interpreting the Results

While the results did not show a benefit of the prebiotic supplement, there are a few important points to consider:

1. The calorie-restricted diet may have been the main driver of improvements. Both groups showed some positive changes, likely due to the weight loss and healthier eating patterns.

2. The study was relatively short at only 8 weeks. It’s possible that a longer intervention period would be needed to see effects from the prebiotic.

3. The dose or type of prebiotic used may not have been optimal. Different prebiotic fibers or doses could potentially show different results.

4. The participants’ gut bacteria were not analyzed. Without this information, it’s unclear whether the prebiotic supplement actually changed the gut microbiome.

5. The study only included women with mild to moderate depression who were already taking antidepressants. The results may not apply to men, people with more severe depression, or those not taking medication.

Conclusions

• An 8-week inulin supplement did not provide additional benefits for depression symptoms or inflammatory markers compared to placebo in women with obesity and depression following a calorie-restricted diet.

• More research is still needed on the potential mood effects of prebiotics, including studies with larger sample sizes, longer durations, and analysis of changes to gut bacteria.

• For women with both obesity and depression, a supervised calorie-restricted diet may help improve both weight and mood symptoms. However, any major dietary changes should be discussed with a healthcare provider first.

While this particular study did not find benefits of the prebiotic supplement, it adds to our understanding of the complex relationships between diet, gut health, inflammation, and mood. As research in this area continues, we may gain more insights into how dietary approaches could be used alongside other treatments to help people with depression and obesity.