Prebiotics, Probiotics, Synbiotics for ADHD May Improve Symptoms in Children (2024 Review)

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Probiotics and prebiotics show potential benefits in improving symptoms and quality of life in children with ADHD, but more extensive studies are needed to confirm these effects.

Highlights:

  1. Positive Impact on Functioning: Lactobacillus rhamnosus GG (LGG) supplementation improved emotional, physical, social, and school functioning in children with ADHD.
  2. Reduction in Inflammation: Synbiotic 2000 reduced markers of intestinal and vascular inflammation in children with ADHD, partially through increased SCFA levels.
  3. Improvement in Symptoms: Some studies indicated that probiotics and synbiotics could improve ADHD symptoms such as inattention and hyperactivity/impulsivity.
  4. Mixed Results: While several studies showed benefits, others reported no significant impact on cognitive function or gut microbiota composition.
  5. Need for Further Research: Longer, larger-scale studies with diverse age groups and various evaluation techniques are required to better understand the effects of prebiotics and probiotics on ADHD.

Source: Neuropsychopharmacology Reports (2024)

Major Findings: Probiotics & Prebiotics for ADHD (2024 Review)

Allahyari et al. conducted a systematic review to evaluate the effects of prebiotics, probiotics, and synbiotics in patients with ADHD – below are the major findings.

1. Positive Impact on ADHD Functioning

Lactobacillus rhamnosus GG (LGG): Studies showed that children with ADHD who received LGG supplementation exhibited significant improvements in emotional, physical, social, and school functioning compared to those who received a placebo. This indicates that LGG may help enhance the overall quality of life for these children.

Health-Related Quality of Life: Children taking LGG had better scores in areas such as emotional well-being and social interactions, suggesting that probiotics might support broader aspects of health beyond just reducing ADHD symptoms.

2. Reduction in Inflammation

Synbiotic 2000: This combination of probiotics and prebiotics was found to reduce markers of inflammation in the intestines and blood vessels of children with ADHD. Inflammation is linked to various health issues, and its reduction suggests a potential pathway through which synbiotics may alleviate ADHD symptoms.

Increase in Short-Chain Fatty Acids (SCFA): Synbiotic 2000 increased the levels of SCFAs, which are beneficial compounds produced by gut bacteria. SCFAs are known to play a role in reducing inflammation and supporting gut health.

3. Improvement in ADHD Symptoms

Probiotics and ADHD Symptoms: Several studies reported that probiotic supplementation could improve symptoms of ADHD, such as inattention and hyperactivity/impulsivity. For example, a study using a specific probiotic strain, Lactobacillus reuteri, showed significant reductions in ADHD rating scales over an 8-week period.

Combination with Medication: Probiotics combined with conventional ADHD medication (like Ritalin) showed enhanced benefits, suggesting that probiotics might work well as an adjunct therapy, improving the effectiveness of existing treatments.

4. Mixed Results in Cognitive Function & Gut Composition

Cognitive Function: Not all studies found a positive impact on cognitive function. Some reported no significant changes, indicating that the benefits of probiotics may vary depending on the specific strains used, the dosages, and individual differences among children.

Gut Microbiota Composition: Changes in gut microbiota composition were inconsistent across studies. While some showed significant alterations in the types of bacteria present, others did not find notable differences, suggesting that more research is needed to understand how probiotics affect gut health in children with ADHD.

5. Need for Further Research

Larger & Longer Studies: The review highlighted the necessity for larger studies with more participants and longer follow-up periods to confirm the beneficial effects of probiotics and prebiotics on ADHD.

Diverse Age Groups & Evaluation Techniques: Future research should include a variety of age groups and use different methods, such as in vivo observations, to provide a comprehensive understanding of how these supplements impact ADHD.

(Related: Probiotics, Prebiotics, Synbiotics for Depression)

Study Details: Probiotics & Prebiotics in ADHD (2024)

Sample

  • 7 Randomized Controlled Trials (RCTs)
  • 2 Cohort Studies

Methods

  • Search Strategy: Comprehensive searches were conducted in PubMed/MEDLINE, Scopus, EMBASE, ISI Web of Science, Cochrane Library, ClinicalTrials.gov, and Google Scholar. Both MeSH and non-MeSH terms were used to ensure inclusivity of relevant studies.
  • Eligibility Criteria: Included studies: Clinical trials and cohort studies evaluating the effects of probiotics and prebiotics on children with ADHD. Excluded studies: Those not providing sufficient outcome information, shorter than 2-week follow-up periods, or conducted before the year 2000.
  • Quality Assessment: The Revised Cochrane risk-of-bias tool (RoB 2) was used to evaluate the risk of bias across several domains, including random-sequence generation, allocation concealment, blinding, incomplete outcome data, selective reporting, and other potential threats to validity.

Limitations

  • Variability in Study Designs: Differences in probiotic strains, dosages, and study designs made direct comparisons challenging.
  • Small Sample Sizes: Many studies had limited participant numbers, reducing the generalizability of the findings.
  • Short Follow-Up Periods: Most studies had relatively short durations, which may not capture long-term effects.
  • Mixed Results: Inconsistencies in outcomes, particularly regarding cognitive function and gut microbiota composition, highlight the need for further research.

(Related: Probiotics & Antioxidants May Help Treat Binge Drinking)

Practical Takeaways: ADHD vs. Probiotics, Prebiotics, Synbiotics (2024)

Based on the findings from the systematic review, here are recommendations for individuals with ADHD considering probiotic and prebiotic supplementation.

Supplements with Strongest Evidence

Lactobacillus rhamnosus GG (LGG)

  • Evidence: Multiple studies in the review indicated that LGG supplementation significantly improved emotional, physical, social, and school functioning in children with ADHD.
  • Recommendation: Consider LGG probiotic supplements as they have shown potential benefits in enhancing overall quality of life and health-related functioning for children with ADHD.
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Synbiotic 2000

  • Evidence: This combination of probiotics and prebiotics was found to reduce markers of intestinal and vascular inflammation and increase levels of short-chain fatty acids (SCFAs), which are beneficial for gut health.
  • Recommendation: Synbiotic 2000 could be considered for reducing inflammation and possibly improving ADHD symptoms through gut microbiota modulation.

Bifidobacterium bifidum

  • Evidence: Supplementation with Bifidobacterium bifidum (Bf-688) improved inattention and hyperactivity/impulsivity symptoms in children with ADHD and altered gut microbiota composition positively.
  • Recommendation: Bifidobacterium bifidum supplements may be beneficial for reducing ADHD symptoms and improving gut health.

Lactobacillus reuteri & Multi-strain Probiotics

  • Evidence: Some studies reported that multi-strain probiotic supplements, including Lactobacillus reuteri, showed improvements in ADHD symptoms, anxiety levels, and metabolic features.
  • Recommendation: Multi-strain probiotic supplements that include Lactobacillus reuteri might be considered for their potential to improve a range of ADHD-related symptoms.

General Recommendations

  1. Consult Healthcare Providers: Before starting any supplementation, it is crucial to consult with a healthcare provider to ensure safety and appropriateness based on individual health needs.
  2. Monitor Progress: Keep track of any changes in symptoms and overall health after starting supplementation. Regular follow-ups with a healthcare provider can help adjust the regimen as needed.
  3. Consider Combination with Medication: Some studies indicated that probiotics could enhance the effects of conventional ADHD medications. Discuss with a healthcare provider the possibility of combining probiotics with existing treatments.
  4. Dietary Sources: In addition to supplements, incorporating probiotic-rich foods like yogurt, kefir, sauerkraut, and prebiotic-rich foods like onions, garlic, and bananas into the diet may support gut health and potentially benefit ADHD symptoms.

How Probiotics & Prebiotics May Improve ADHD (Mechanisms)

The systematic review highlights several potential mechanisms by which probiotics and prebiotics could improve symptoms of ADHD.

These mechanisms revolve around the gut-brain axis, inflammation reduction, production of beneficial metabolites, and modulation of gut microbiota. Here are the specific mechanisms:

1. Gut-Brain Axis Modulation

Bidirectional Communication: The gut-brain axis is a bidirectional communication network between the gastrointestinal tract and the central nervous system. Probiotics and prebiotics can influence this axis by altering gut microbiota, which in turn can affect brain function and behavior.

Neurotransmitter Production: Certain probiotics can produce neurotransmitters such as serotonin and gamma-aminobutyric acid (GABA). These neurotransmitters play a role in mood regulation and cognitive function, potentially improving ADHD symptoms.

2. Reduction of Inflammation

Intestinal and Systemic Inflammation: Probiotics like Synbiotic 2000 have been shown to reduce markers of intestinal and vascular inflammation. Inflammation is linked to various psychiatric and neurodevelopmental disorders, including ADHD. By reducing inflammation, probiotics may alleviate some of the symptoms associated with ADHD.

SCFA Production: Probiotics increase the production of short-chain fatty acids (SCFAs) such as butyrate, propionate, and acetate. SCFAs have anti-inflammatory properties and can help maintain gut barrier integrity, preventing systemic inflammation that can affect brain function.

3. Modulation of Gut Microbiota

Microbiota Diversity: ADHD is associated with altered gut microbiota composition. Probiotics and prebiotics can increase the diversity and abundance of beneficial gut bacteria, such as Lactobacilli and Bifidobacteria, which are often depleted in individuals with ADHD.

Pathogen Inhibition: Probiotics can inhibit the growth of pathogenic bacteria in the gut, reducing the risk of infections and inflammation that can negatively impact brain health and behavior.

4. Metabolic Pathways

Enhanced Metabolic Functions: Probiotics can improve metabolic functions by producing vitamins, enzymes, and other bioactive compounds that support overall health. Improved metabolism can lead to better energy levels and cognitive function, which may help reduce ADHD symptoms.

Antioxidant Effects: Some probiotics exhibit antioxidant properties, reducing oxidative stress in the body. Oxidative stress is implicated in the pathology of ADHD, and reducing it may help improve symptoms.

5. Immune System Regulation

Immune Modulation: Probiotics can modulate the immune system by promoting the production of anti-inflammatory cytokines and suppressing pro-inflammatory cytokines. This immune regulation can contribute to reducing neuroinflammation and improving ADHD symptoms.

Gut Barrier Integrity: By strengthening the gut barrier, probiotics prevent the translocation of harmful bacteria and toxins into the bloodstream, which can trigger immune responses and inflammation affecting the brain.

Conclusion: Probiotics, Prebiotics, Synbiotics in ADHD

The systematic review suggests that probiotics and prebiotics may offer beneficial effects for children with ADHD, improving emotional, physical, social, and academic functioning.

Lactobacillus rhamnosus GG (LGG) and Synbiotic 2000, in particular, have shown promising results in enhancing quality of life and reducing inflammation.

These supplements potentially modulate the gut-brain axis, decrease systemic inflammation, and support a healthier gut microbiota composition.

However, the evidence is mixed, and further research with larger, longer-term studies is needed to confirm these benefits and understand the underlying mechanisms.

As such, probiotics and prebiotics could be considered as part of a comprehensive ADHD management plan, but should be used under medical supervision.

References