The findings followed the identification of elevated pro-inflammatory markers, such as sICAM-1 and sVCAM-1, at baseline in adults with ADHD. The markers were further heightened in children, particularly those taking ADHD-related medication, with reductions in formic, acetic, and propionic acid SCFA levels compared to the adults.
The administered Synbiotic 2000 contained three lactic acid bacteria, including Pediococcus pentosaceus, Lactobacillus casei ssp paracasei, and Lactobacillus plantarum, as well as 2.5g each of the fermentable fibres; beta-glucan, inulin, pectin and resistant.
“This study is the first to report the effects of a synbiotic intervention on plasma levels of immune activity markers and SCFAs in children and adults with ADHD,” the Swedish researchers emphasise.
They add that the findings suggest “that Synbiotic 2000, in children with ADHD, reduces markers of intestinal and vascular inflammation, the latter in part through increasing SCFA levels. The findings warrant further studies to determine if persons with ADHD would benefit inflammation-wise from dietary intake of Synbiotic 2000 or a similar synbiotic.”
Microbiota and the mind
ADHD is a common neurological disorder with development occurring in childhood, resulting in a global prevalence of 5% in children and 3% in adults. With common symptoms including inattention and hyperactivity, the disorder can have significant impacts to quality of life. Whilst largely attributed to genetics, it is understood that environmental factors, such as prenatal inflammatory exposure, can influence its development.
Additionally, following observations of the occurrence of ADHD with further conditions associated with immune dysfunction, such as celiac disease and asthma, proposals have drawn parallels between immune response alterations and the condition.
Recent research has been mounting favouring the evidence of the role of the gut microbiota in immunity, with subsequent studies highlighting the differing compositions of those with ADHD. Following this, the researchers conducted a previous RCT using Synbiotic 2000, with three lactic acid bacilli species and four types of dietary fibres, which demonstrated improved emotion regulation in those with ADHD with elevated baseline inflammatory markers.
Thus, they sought to conduct the present RCT to understand the mechanisms of action behind this effect, observing concentrations of immune marks and SCFAs in adults and children with ADHD following administration with the Synbiotic 2000.
Study
The study utilised the participants enrolled in the previous trial, consisting of 248 patients diagnosed with ADHD, as well as 72 healthy adults. Subjects were then randomly assigned to either the Synbiotic 2000 treatment group or the placebo group, with blood tests and interviews taking place at baseline and following the nine weeks of intervention.
It was observed that adults with ADHD had baseline readings suggesting higher pro-inflammatory markers, such as elevated sICAM-1 and sVCAM-1, as well as lower SCFA levels compared with the controls. Children with ADHD had even higher baseline inflammatory marks, including IL-12/IL-23p40 and IL-2Rα, as well as lower formic, acetic, and propionic acid levels compared with the ADHD-diagnosed adults. These readings more were more abnormal in children receiving associated medication.
Following the Synbiotic 2000 treatment, the medicated children demonstrated reduced levels of these inflammatory markers, as well as increased propionic acid levels.
Explained
Whilst there was not an overall statistically significant group effect of the synbiotic compared to the placebo, analysing by age-group was deemed appropriate following the identification of different baseline measures in children and adults.
“These findings suggest that treatment with Synbiotic 2000 reduces IL12/IL-23p40 and sICAM-1 and increases propionic acid levels in children with ADHD. Propionic acid, together with formic and acetic acid, may contribute to the lowering of the higher-than-normal sICAM-1 levels.”
The researchers highlight that the inflammatory markers identified to be reduced are involved in the promotion of Th1 and Th17 expansion, as well as the pathology of inflammatory bowel disease (IBD). This mirrors previous evidence suggesting the overexpression of GI symptoms in those with ADHD, highlighting a potential target for dietary intervention to alleviate such symptoms in patients.
Whilst the use of an RCT with strong sample size enabled for validity in the findings, it is important to note the absence of a healthy control group for children with ADHD and subsequent reference values for comparison. Therefore, further studies are required to confirm these findings.
Source: Nutrients
https://doi.org/10.3390/nu15051293
“Effects of a Synbiotic on Plasma Immune Activity Markers and Short-Chain Fatty Acids in Children and Adults with ADHD—A Randomized Controlled Trial”
by Liu L. Yang , Miranda Stiernborg, Elin Skott, Jingjing Xu, Yujiao Wu, Rikard Landberg, Samsul Arefin, Karolina Kublickiene, Vincent Millischer, Ida A. K. Nilsson, Martin Schalling, MaiBritt Giacobini and Catharina Lavebratt