Effect of <i>Bifidobacterium longum</i> on cognition and microbiota in post-stroke patients: a single-blinded, controlled trial

Stroke is the major leading cause of death globally, and has a high disability rate. Malnutrition, cognitive dysfunction, motor impairment, and gut dysbiosis are observed in stroke patients. Our study explored the effects of <i>Bifidobacterium longum</i> OLP-01, a probiotic from an Olympics gold medalist, on cognitive function and gut microbiota as the primary outcomes, and on nutritional status and physical performance as the secondary outcomes in post-stroke patients. The study was a single-blinded, randomized, placebo-controlled trial. We recruited 22 post-stroke patients. Participants received either placebo (placebo group, <i>n</i> = 10) or 2 × 10¹⁰ colony-forming units (CFU) of <i>Bifidobacterium longum</i> OLP-01 powder (OLP-01 group, <i>n</i> = 12) daily for 12 weeks. Nutritional status was assessed using Mini Nutritional Assessment (MNA). Cognitive function was evaluated by Montreal Cognitive Assessment (MoCA), Trail-Making Tests, and Stroop Color Naming Test. Physical performance was measured using Timed Up and Go Test and 6-Minute Walk Test. Blood and stool samples were collected for biochemical and gut microbiota analyses. The OLP-01 group increased MoCA scores, decreased time to completion of Trail-Making Tests, and had greater accuracy on incongruent in Stroop Color Naming Test, but decreased MNA scores within the normal ranges. The cognitive-related gut microbiota strain showed differences between the two groups. Supplementation of <i>Bifidobacterium longum</i> OLP-01 at a dose of 2 × 10¹⁰ CFU daily for 12 weeks improved cognitive function and changes gut microbiota, but did not alter physical performance in post-stroke patients.