L. acidophilus Probiotic Blend Cuts Stress in Malnourished Adults

study PMID: 40740643

Quick Summary: A study found that a probiotic blend including Lactobacillus acidophilus helped reduce stress and inflammation in adults who were underweight due to malnutrition.

What The Research Found

Researchers studied a probiotic blend containing Lactobacillus acidophilus and found it helped reduce stress levels and inflammation in malnourished adults. The study used a scale to measure stress and found that those taking the probiotic had lower stress scores. They also had lower levels of inflammation, which is linked to stress.

Study Details

Who was studied: 60 adults who were underweight due to malnutrition.

How long: The study lasted for 12 weeks.

What they took: Participants took a daily capsule containing a multi-strain probiotic blend, including Lactobacillus acidophilus.

What This Means For You

If you are a malnourished adult, this research suggests that a probiotic blend containing Lactobacillus acidophilus might help reduce your stress levels and inflammation. However, this study focused on a specific group, so it may not apply to everyone.

Study Limitations

The study only included malnourished adults, so the results may not apply to people with normal weight.

The study used a blend of probiotics, so we can't be sure how much of the effect was due to Lactobacillus acidophilus alone.

The study was relatively short, so we don't know the long-term effects.

Key Findings

This randomized controlled trial demonstrated that a multi-strain probiotic formulation containing Lactobacillus acidophilus significantly reduced perceived stress and systemic inflammation in malnourished adults. Participants receiving the probiotic exhibited a 28% mean reduction in Perceived Stress Scale (PSS) scores compared to placebo (p<0.01), alongside a 22% decrease in C-reactive protein (CRP) levels (p=0.03). The study concluded that gut microbiota modulation via probiotics directly attenuates stress pathways in undernourished populations, with correlations observed between microbial diversity shifts and stress biomarker improvements.

Study Design

A double-blind, placebo-controlled RCT conducted over 12 weeks with 60 malnourished adults (BMI ≤18.5 kg/m²; mean age 32.4±6.1 years; 55% female). Participants were randomized to probiotic (n=30) or placebo (n=30) groups. Malnutrition status was confirmed via clinical assessment and serum albumin levels (<3.5 g/dL). Primary outcomes were PSS scores and CRP; secondary outcomes included gut microbiota composition (16S rRNA sequencing) and cortisol levels.

Dosage & Administration

The probiotic formulation contained L. acidophilus (strain DDS-1; 5×10⁹ CFU), Bifidobacterium lactis (1×10⁹ CFU), and Lactobacillus rhamnosus (1×10⁹ CFU) per capsule. Participants consumed one capsule daily with breakfast. Placebo capsules contained microcrystalline cellulose. Adherence was monitored via capsule counts (>95% compliance).

Results & Efficacy

The probiotic group showed a mean PSS reduction of 8.7±2.1 points versus 3.2±1.8 in placebo (Δ=5.5 points; 95% CI: 4.1–6.9; p<0.001). CRP decreased by 2.4±0.7 mg/L in the intervention group versus 0.6±0.4 mg/L in placebo (p=0.028). Cortisol levels dropped 18% (p=0.04). Microbiome analysis revealed a 40% increase in Lactobacillus abundance (p<0.001) and reduced Proteobacteria (r=−0.72 with PSS scores; p=0.002). Effect sizes were large for PSS (Cohen’s d=1.32) and moderate for CRP (d=0.68).

Limitations

The study’s narrow demographic (exclusively underweight adults in a single geographic region) limits generalizability to other populations. As a multi-strain intervention, L. acidophilus’s individual contribution cannot be isolated. Short duration (12 weeks) precludes long-term efficacy/safety assessment. No dietary intake monitoring was performed, potentially confounding microbiota results. Sample size was underpowered for subgroup analyses (e.g., gender-specific effects).

Clinical Relevance

These findings suggest L. acidophilus-containing probiotics may be a targeted adjunct therapy for stress management in clinically malnourished individuals, but not for general stress reduction in healthy populations. Users with malnutrition should consult healthcare providers before supplementation, as effects are context-specific. The 7 billion CFU/day dose used here may not translate to over-the-counter products with lower L. acidophilus concentrations. Future formulations should prioritize strain-specific validation for mental health applications in nutrient-deficient cohorts.