Safety of Excessive Intake of a Supplement Containing Dry Acetic Acid Bacterium Powder

Background　While acetic acid bacteria has not been associated with toxicities in short-term animal studies, consumption of acetic acid bacteria themselves as a supplement has not been evaluated in humans. Here, we have conducted a study to confirm the safety of acetic acid bacteria when taken in a large amount. Methods　We tested soft capsules that contained an extract of an acetic acid bacteria （Gluconoacetobacter hansenii GK-1）. Each capsule contained 45 mg of dry acetic acid bacterium powder, and each subject took 450 mg acetic acid bacteria per day. The subjects were men and women aged between 20 and 69 years who drank alcohol twice or more per week. Subjects took acetic acid bacteria in quantities 5 times the reference amount recommended in the Japanese Ministry of Health, Labour and Welfareʼs Guideline of Food for Specified Health Uses Subjects for 4 weeks. Subjects completed physical examinations, complete blood counts, blood biochemistry, and urinalysis, in addition to completing a diary of intake and subjective symptoms every day during the study. Results　Consumption of a food supplement containing dry acetic acid bacterium powder for 4 weeks was not associated with any significant adverse effects on weight, blood pressure, hematology, or clinical chemistry related to liver and kidney function. Although there were significant differences seen in some variables over the study period, these changes were all within the range of the reference values. Conclusions　We observed no harms related to the daily consumption of a food supplement containing 450 mg of dry acetic acid bacterium powder over 4 weeks.