Selenium & Probiotics for Alzheimer's: Does it Help?

randomized-controlled-trial PMID: 30642737

Quick Summary: A study found that taking selenium and probiotics together might help people with Alzheimer's disease. This combination seemed to improve thinking skills and some aspects of their metabolism, like reducing inflammation.

What The Research Found

This research looked at how selenium and probiotics affect people with Alzheimer's. The study showed that taking both:

Improved thinking skills: People scored better on tests of mental function.

Reduced inflammation: Levels of a marker of inflammation in the blood went down.

Improved metabolism: This means better control of blood sugar and cholesterol.

Selenium alone also helped, but the combination of selenium and probiotics seemed to work best.

Study Details

Who was studied: 79 people in Iran, aged 60-90, who had Alzheimer's disease.

How long: The study lasted for 12 weeks (about 3 months).

What they took: Participants were divided into three groups:

Selenium (200 micrograms per day) + a mix of probiotics (containing Lactobacillus acidophilus, Bifidobacterium bifidum, and Bifidobacterium longum)
Selenium alone
A placebo (a "dummy" pill with no active ingredients)

What This Means For You

If you or a loved one has Alzheimer's, this research suggests that adding selenium and probiotics to your routine might be helpful.

Talk to your doctor: Before starting any new supplements, it's important to talk to your doctor. They can advise you on the right dosage and whether it's safe for you, especially since selenium can be harmful in high doses.

Consider the ingredients: If you're interested in trying this, look for a probiotic supplement that contains the specific strains used in the study.

Study Limitations

It's important to keep these things in mind:

Small study: The study only included 79 people, so more research is needed to confirm these findings.

Specific population: The study was done in Iran, so the results might not be the same for everyone.

Short-term: The study only lasted 3 months. We don't know if the benefits would last longer.

More research needed: We don't know exactly how selenium and probiotics work together to help.

Key Findings

This 12-week randomized trial found that co-supplementation with selenium (200 μg/day) and a probiotic blend (Lactobacillus acidophilus, Bifidobacterium bifidum, B. longum) significantly improved cognitive function (measured by MMSE score: +1.5 ± 1.3 vs. -0.2 ± 1.1 in placebo) and metabolic markers in 79 Iranian adults with Alzheimer’s disease (AD). The combination reduced systemic inflammation (hs-CRP: -1.6 ± 1.4 mg/L vs. +0.1 ± 0.5 in placebo), oxidative stress (total antioxidant capacity: +89.4 ± 129.6 vs. -0.7 ± 27.2 in placebo), and insulin resistance (HOMA-IR: -0.5 ± 0.6 vs. +0.1 ± 0.4 in placebo). Selenium alone also improved metabolic profiles but was less effective than the combination.

Study Design

A randomized, double-blind, controlled trial conducted in Iran (2019) with 79 participants (aged 60–90 years) diagnosed with AD. Subjects were divided into three groups:
1. Probiotic + selenium (n=27)
2. Selenium alone (n=26)
3. Placebo (n=26)
Outcomes were assessed at baseline and post-intervention, with a 12-week follow-up period.

Dosage & Administration

Selenium: 200 μg/day (as sodium selenite)
Probiotic: 2 × 10⁹ CFUs/day of a blend containing L. acidophilus, B. bifidum, and B. longum
Administration: Daily oral capsules, consumed with meals.

Results & Efficacy

Cognitive Function: Probiotic + selenium increased MMSE scores by 1.5 ± 1.3 vs. 0.5 ± 1.2 with selenium alone and -0.2 ± 1.1 in placebo (P < 0.001 for combination vs. others).
Inflammation: hs-CRP decreased by 1.6 ± 1.4 mg/L in the combination group vs. 0.1 ± 0.5 mg/L in placebo (P < 0.001).
Insulin Resistance: Combination reduced HOMA-IR by 0.5 ± 0.6 vs. +0.1 ± 0.4 in placebo (P < 0.001).
Lipid Profiles: Triglycerides (-17.9 ± 26.1 vs. +0.3 ± 9.3 mg/dL), LDL (-8.8 ± 17.8 vs. +2.7 ± 19.0 mg/dL), and total/HDL ratio (-0.3 ± 0.7 vs. +0.3 ± 0.6) improved with combination therapy (P = 0.02–0.005).
Antioxidants: Total glutathione (GSH) increased by 122.8 ± 136.5 μmol/L in the combination group vs. +1.5 ± 53.2 μmol/L in placebo (P = 0.001).

Limitations

Sample Size: Relatively small (n=79), limiting generalizability.
Population Specificity: Participants were Iranian, with no diversity data reported.
Duration: Short-term (12 weeks); long-term effects on AD progression remain unknown.
Mechanistic Gaps: No assessment of gut microbiota changes or direct oxidative stress markers beyond GSH and TAC.
Placebo Composition: Details on placebo ingredients (e.g., inert substances) were not specified.

Clinical Relevance

For individuals with AD, this study suggests that combining selenium with specific probiotics may enhance cognitive function and metabolic health. However, the results should be interpreted cautiously due to the small sample size and lack of mechanistic data. Selenium doses (200 μg/day) align with common supplementation ranges but should be monitored to avoid toxicity. Probiotic strains used were well-defined, though their individual contributions to outcomes were not isolated. Clinicians might consider these supplements as adjuncts to standard AD therapies, pending replication in larger, diverse populations. Patients should consult healthcare providers before use, especially given selenium’s narrow safety margin.

Source: PubMed | Trial Registration: IRCT20170612034497N5