Evaluating probiotic efficacy on weight loss in adults with overweight through a double-blind, placebo-controlled randomized trial

The aim was to assess the weight-reducing effects of various doses of a probiotic dietary supplement and evaluate the tolerance and safety of increased dosage. A 3-month double-blinded, randomized, placebo-controlled trial, followed by a 3-month open phase, was conducted at Karolinska Institutet, Sweden. The probiotic compound AB001 was tested at two doses (single and double) and compared with placebo during the blinded phase, and at triple dose during the open phase. Eighty-one volunteers, 18–45 years old, with overweight were included. The primary outcome was change in weight. Secondary outcomes were changes in; BMI, waist circumference, blood pressure, blood lipids, glucose metabolism, liver enzymes, vitamin levels, and bowel habits. After 3 months (n = 81), no difference in weight, BMI, waist circumference, blood pressure, or biomarkers were observed between the groups. Forty-five individuals continued with triple dose. The group with initial single dose decreased 0.93 ± 4.73 kg (p = 0.34), and the group with double dose initially decreased 1.93 ± 3.70 kg (p = 0.027). Reported changes in bowel habits and gastro-intestinal problems were similar for all doses. The results indicate that a long-term use of at least double dose AB001 may be more beneficial for weight loss than lower doses. However, in the double blinded phase, no differences between groups were found. The probiotic compound AB001 was well tolerated and can safely be used up to double dose for 90 days followed by triple dose for 90 days. Trial registration: Clinicaltrial.gov NCT04897698, registered on 21 May 2021.