The gut-brain axis is implicated in various physiological functions, including neurotransmitters, with the gut microbiome purported to play a role in the pathophysiology of ADHD and could potentially influence early human brain development.
As such, manipulating the microbiome through probiotics intake holds promise for uncovering novel therapeutic approaches.
To investigate the impact of Bifidobacterium bifidum (Bf-688 strain) supplementation on clinical symptoms, body weight changes, and gut microbiome composition in children undergoing drug therapy for ADHD, a 12-week randomised, double-blind, placebo-controlled clinical trial was conducted by researchers in Taiwan.
The study was funded by Chang Gung Memorial Hospital and Taiwan’s Ministry of Science and Technology.
A total of 107 children between the ages of six and 12, who were receiving methylphenidate (MPH) treatment, were enrolled.
They were randomly assigned to two groups — one receiving Bf-688 (daily bacterial count of 5 × 109 CFUs) and the other receiving a placebo consisting of maltodextrin and corn starch. Both supplement and placebo were taken twice daily for 12 weeks.
Compared to the placebo group, the Bf-688 group demonstrated significant improvements in omission errors in the Conners’ Continuous Performance Test (CPT), which evaluates visual attention ability.
The response rates, or hit reaction time (HRT), in both CPT and Conners’ Continuous Auditory Test of Attention (CATA) assessments were also higher in the Bf-688 group than the placebo group.
In addition, the findings revealed significant correlations between CPT HRT, CATA HRT, and N-glycan biosynthesis, which link gut dysbiosis-induced N-glycosylation abnormalities to neurodevelopmental disorders like ADHD.
N-glycosylation is crucial for multicellular life, and a complete absence of it can be fatal during embryonic development. Dysregulation of glycosylation is associated with a wide spectrum of diseases, including cancer, diabetes, cardiovascular disorders, congenital diseases, immunological disorders, and infectious diseases.
“Variations in glycosylation have profound physiological impact because alterations in glycans can significantly affect the structure and function of glycoprotein polypeptide components. Prior research has shown increases in the glycan groups GP11 and DG7, along with a decrease in GP12, in the plasma of individuals with ADHD.
“It is conceivable that differences in glycosylation efficiency could lead to changes in neural signalling and potentially contribute to the development of ADHD. Therefore, our results suggest that the beneficial effects of Bf-688 on ADHD may be mediated through the reshaping of gut dysbiosis and the normalisation of abnormal N-glycosylation processes.”
Rectifying microbiota imbalances
Although the most commonly prescribed psychostimulant medication for ADHD, MPH is known to cause adverse effects in children and adolescents, including reduced appetite, weight loss, and abdominal discomfort.
A previous open-label study by the researchers found that supplementation with Bf-688 was associated with weight gain in drug-naïve children with ADHD.
In the current study, Bf-688 supplementation did not result in additional body weight gain, but this group exhibited a superior outcome in terms of gastrointestinal (GI) symptoms, compared to the placebo group, at week 12.
It has been suggested that the abundance of Bifidobacterium could potentially serve as a biomarker for ADHD due to its involvement in the dopamine neural reward system.
To examine differences in gut microbiota composition pre- and post-intervention, faecal samples were collected at the beginning of the trial (week 0) and at the endpoint (week 12).
Notable differences in abundance of Firmicutes and Bacteroidetes were observed before and after the treatment period, and this was significant solely in the Bf-688 group.
Furthermore, the analysis identified a significant elevation in the Firmicutes to Bacteroidetes (F/B) ratio in the Bf-688 group, while no such increase was seen in the placebo group.
A high F/B ratio has been associated with weight gain, which may counter the side effects of MPH treatment and restore gut microbial balance.
“Our findings show that Bifidobacterium was indeed present at very low levels in the participants, and its abundance significantly increased following intervention. This suggests that Bf-688 supplementation may benefit individuals with ADHD through modulating gut microbiome dysbiosis and alleviating GI symptoms.”
Source: Nutrients
https://doi.org/10.3390/nu16142260
“Add-On Bifidobacterium Bifidum Supplement in Children with Attention-Deficit/Hyperactivity Disorder: A 12-Week Randomized Double-Blind Placebo-Controlled Clinical Trial”
Authors: Liang-Jen Wang, et al
