Probiotic for Depression? New Study on Tryptophan

clinical-trial PMID: 34875345

Quick Summary: Researchers found that a specific probiotic, Bifidobacterium breve CCFM1025, helped reduce symptoms of major depression. This probiotic may work by affecting how the body uses tryptophan, an amino acid important for mood.

Can Probiotics Help With Depression?

This study looked at whether a probiotic could help people with major depression. The probiotic, Bifidobacterium breve CCFM1025, showed promising results. People taking the probiotic reported fewer symptoms of depression compared to those who took a placebo (a sugar pill).

What The Research Found

The study found that the probiotic:

Improved Depression Symptoms: People taking the probiotic had lower scores on depression scales, meaning they felt better.

Impacted Tryptophan: The probiotic seemed to affect how the body used tryptophan. Tryptophan is an amino acid that the body uses to make serotonin, a "feel-good" brain chemical.

May Help Gut Issues: The study also suggested the probiotic could help with some gut-related problems often linked to depression.

Study Details

Who was studied: 45 adults in China diagnosed with major depression.

How long: The study lasted for 8 weeks.

What they took: Participants were randomly assigned to take either the probiotic (Bifidobacterium breve CCFM1025) or a placebo (a dummy pill). The probiotic dose was 10⁹ CFU (colony-forming units) per day.

What This Means For You

This research suggests that probiotics could be a helpful addition to depression treatment. If you struggle with depression, especially if you also have gut issues, talking to your doctor about probiotics might be a good idea. Remember, this is just one study, and more research is needed.

Consider talking to your doctor: Before taking any new supplements, especially if you're already on medication for depression.

Look for probiotics with this specific strain: If your doctor approves, you could look for probiotics containing Bifidobacterium breve CCFM1025.

Study Limitations

Small Study: The study only included a small number of people, so the results might not apply to everyone.

Short Duration: The study only lasted 8 weeks, so we don't know if the effects would last longer.

More Research Needed: This is a promising start, but more research is needed to confirm these findings and understand how the probiotic works.

Limited Population: The study was done on Chinese adults, so the results might be different for other populations.

Key Findings

The study found that Bifidobacterium breve CCFM1025 supplementation significantly improved depression symptoms in patients with major depressive disorder (MDD) compared to placebo. This effect was linked to changes in gut microbiome diversity and tryptophan metabolism, including reduced serum serotonin turnover. Emotional and gastrointestinal symptoms, assessed via BPRS and GSRS factor analysis, were associated with serotonergic system modulation.

Study Design

This was a randomized, double-blind, placebo-controlled clinical trial registered in China (ChiCTR2100046321). A total of 45 Chinese adults diagnosed with MDD were assigned to placebo (n = 25) or CCFM1025 (n = 20). The intervention lasted 8 weeks, with outcomes measured using standardized scales (HDRS-24, MADRS, BPRS, GSRS) and biochemical markers (serotonin turnover).

Dosage & Administration

Participants received freeze-dried B. breve CCFM1025 at a dose of 10⁹ CFU/day (colony-forming units) orally, administered once daily. The placebo group received identical capsules without active bacteria.

Results & Efficacy

HDRS-24 scores: CCFM1025 improved depression symptoms more than placebo (mean difference: 10.40 vs. 6.44; t(43) = 2.163, p = 0.036, Cohen’s d = 0.64).
MADRS scores: Similar improvements were observed (mean difference: 9.60 vs. 4.92; t(43) = 2.152, p = 0.037, d = 0.645).
Serotonin turnover: CCFM1025 reduced serum serotonin turnover (mean change: 0.27 vs. -0.01; t(43) = 2.267, p = 0.029, d = 0.681).
Mechanisms: Factor analysis suggested emotional and gastrointestinal benefits were mediated by the serotonergic system, potentially driven by altered gut microbiome alpha diversity and tryptophan/indole derivatives.

Limitations

Small sample size (n = 45), limiting statistical power and generalizability.
Short duration (8 weeks); long-term efficacy and safety unknown.
Mechanistic insights (e.g., microbiome composition, indole levels) were inferred but not directly measured.
No active comparator group (e.g., standard antidepressants).
Demographics restricted to Chinese adults; cross-population validation needed.

Clinical Relevance

This trial supports B. breve CCFM1025 as a potential psychobiotic for MDD, particularly for individuals with comorbid gastrointestinal symptoms. The modulation of tryptophan metabolism highlights the gut-brain axis as a therapeutic target. However, larger, longer trials are required to confirm these effects and establish clinical guidelines. Supplement users should consult healthcare providers before use, as probiotic responses vary by strain and individual.

Source: PubMed | Date: 2022 | Type: Clinical Trial