Study finds that proprietary strain from Probi improved cognitive health in moderately stressed subjects

Photo © iStockphoto.com/BartekSzewczyk

A recent study published in Nutrients¹ found that a proprietary probiotic strain Lactiplantibacillus plantarum, marketed as HEAL9 by Probi, was able to improve cognition is subjects with moderate stress. In the study, 129 subjects between the ages of 21 and 52 years of age were randomized to consume either the probiotic strain or placebo for 12 weeks. Researchers used Cohen’s Perceived Stress Scale (PSS) to measure subjective feelings of stress, the Profile of Mood State (POMS) questionnaire to assess mood state, and the Pittsburg Sleep Quality Index (PSQI) questionnaire to assess sleep quality. To assess cognitive performance, researchers utilized The Competency Assessment (COMPASS) battery of cognitive assessment tools. They also measured Cortisol Awakening Response which is the change in cortisol concentration in the first hour after awakening from a night’s sleep.

Results showed that perceived stress and awakening cortisol saw significant reductions in both groups. However, compared to placebo, subjects taking the probiotic saw significant improvements in four cognition tests. These tests were the rapid information processing test, numeric working memory test, paired associated learning, and word recall. Compared to placebo, researchers also observed a tendency for better improvement for three mood subscales of confusion-bewilderment, anger-hostility, and depression-dejection. Additionally, there were fewer subjects with poor sleep in the probiotic group, compared to placebo.

“Mental health and wellness is a field with significant growth potential. This complementary study demonstrates that our strain HEAL9 has a strong clinically proven effect in the gut-brain area and boosts our confidence ahead of the official launch of our new product at Supply Side West in Las Vegas in October." says Anita Johansen, CEO of Probi, in a press release.

While the study did find a substantial placebo effect in measures of perceived stress, awakening cortisol, and some mood subscales, the improvements subjects taking the probiotic experienced to their working memory, memory, and learning and visuospatial memory were among the most significant. There are a number of potential mechanisms the researchers point to that may contribute to the impact of the probiotic strain on cognitive health. For one, the researchers point to the strain’s ability to reach the gastrointestinal tract, and adhering to human mucosa cells. Other facts that may influence cognitive function are the metabolism of tryptophan and kynurenine, as well as the level of brain-derived neurotrophic factor, but the present study found no measurable impact on these factors, pointing to a need for further investigation.

Researchers did however observe a more stable inflammatory status in subjects taking the probiotic, compared to placebo. Stress has been associated with inflammation, and therefore, controlling inflammatory markers such as fractalkine which is prominent in the intestinal epithelium, and TGF-β may be underlying mechanisms for the impact of the probiotic strain on cognitive health.

Reference

1. Önning, G.; Montelius, C.; Hillman, M.; Larsson, N. Intake of Lactiplantibacillus plantarum HEAL9 Improves Cognition in Moderately Stressed Subjects: A Randomized Controlled Study. Nutrients, 2023, 15(15): 3466. DOI: 10.3390/nu15153466