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Probiotics help quell ADHD, study suggests
A multi-strain probiotic lessened some ADHD symptoms and improved academic performance in a study of college students in Israel.
3 Min Read
At a Glance
- ADHD affects millions of adults worldwide.
- Probiotics are postulated to help via the gut-brain axis.
- A study using a multi-strain probiotic showed some positive results.
A new study suggests that a multi-strain probiotic intervention can reduce some of the issues caused by ADHD.
The new study was published in the journal Scientific Reports and was the work of researchers associated with Tel Hai College in Israel.
The study authors claimed no funding grant or support from a company, but acknowledged the probiotics used and placebos were donated by Altman Health, an Israeli probiotics manufacturer.
The authors noted ADHD affects an estimated 3% to 4% of the adult population worldwide.
The U.S. Centers for Disease Control and Prevention puts the number even higher at 6% of the adult population in the U.S., or more than 15 million people.
Dysregulated neurotransmitters postulated as part of problem
The researchers noted modern understanding of ADHD involves the dysregulated secretion of some neurotransmitters and bioactive factors, including cortisol, “suggesting that abnormal diurnal cortisol secretion patterns and cortisol hyperreactivity, hallmarks of HPA axis dysregulation, are correlated with ADHD’s behavioral manifestations.”
Probiotics have demonstrated effects on the secretion of cortisol. Via the gut-brain axis, probiotic supplementation could have a significant effect on ADHD symptoms, according to the researchers.
To test their hypothesis, the researchers recruited 67 students from Tel Hai College who were between the ages of 19 and 30. All of the subjects were diagnosed with ADHD using an online assessment tool that was verified by a psychiatrist or psychologist. None of the subjects were taking medication to treat their ADHD symptoms.
About two thirds of the subjects were women.
The subjects were divided into two groups with each taking the probiotic intervention or a placebo daily for three months.
Multi-strain probiotic used
The multi-strain probiotic product consisted of 8 billion CFU (colony forming units) each of L. helveticus, B. animalis ssp. lactis, Enterococcus faecium, B. longum and Bacillus subtilis. The researchers did not further characterize the strains with alpha-numeric designations.
The subjects recorded their dietary intake through a questionnaire. A questionnaire approach was used to assess their quality of life as well.
For ADHD-specific measurements, the researchers relied on a validated online test that measured attention, hyperactivity, impulsivity and timing.
They also recorded the grades the students received in their courses in the semester before the study and during the course of the intervention.
To assess cortisol secretions, the researchers relied on the chemical analysis of fingernail clippings from each participant.
Results present mixed bag
The results were mixed. Some of the ADHD symptoms measured through the online tool improved in the probiotic group, such as hyperactivity. Others did not, such as inattention and impulsiveness.
The subjects in the probiotic group, on average, achieved higher grades during the study period than they did in the previous semester. The changes in average grades in the placebo group did not reach statistical significance. Only about two thirds of the subjects provided a detailed enough picture of their grades for an analysis to be performed.
How these effects were achieved was murky because the cortisol levels — as measured in the fingernail analysis —did not show significant changes throughout the study period.
The researchers still determined the results were promising enough to warrant a larger, follow-up study.
“This double-blind RCT [randomized controlled trial] was the first to show significant improvements in ADHD symptoms among college students receiving probiotic supplementation. This study suggests probiotics as a potential treatment approach to ease ADHD symptoms in this population,” the researchers concluded. “The presented findings set the stage for larger multi-center trials designed to examine multi-strain probiotic formulas to enhance functional outcomes in individuals with ADHD.”
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