Effects of 12-wk Lactobacillus plantarum OLL2712 treatment on glucose metabolism and chronic inflammation in prediabetic individuals: A single-arm pilot study

•Lactobacillus plantarum OLL2712 is effective for individuals who are prediabetic.•The ingestion of OLL2712 cells significantly improved fasting plasma glucose levels.•Serum glycoalbumin levels and insulin resistance indexes were improved.•The intervention also suppressed serum monocyte chemotactic protein-1 and interleukin-6 levels.•OLL2712 might exert anti-diabetic effects by suppressing chronic inflammation. Previously, we demonstrated that the administration of heat-killed OLL2712 cells suppressed chronic inflammation and improved hyperglycemia in a mouse model of obesity and diabetes. The aim of this study was to preliminarily examine the effect of OLL2712 supplementation on glucose metabolism and chronic inflammation in prediabetic subjects. This study was a prospective, 12-wk, single-arm, open trial, followed by a 4-wk posttreatment period. Inclusion criteria were fasting plasma glucose levels of 105 to 130 mg/dL in an age range of 35 to 65 y. Thirty individuals consumed a dairy beverage containing ∼1 × 1010 heat-killed OLL2712 cells for 12 wk. The ingestion of the OLL2712 beverage significantly improved fasting plasma glucose levels, serum glycoalbumin levels, and insulin resistance indexes compared with baseline levels. The intervention also suppressed serum monocyte chemotactic protein-1 and interleukin-6 levels, which are proinflammatory cytokines involved in the development of insulin resistance and hyperglycemia. Furthermore, stratified analysis by these proinflammatory cytokine levels revealed that the beneficial effects of OLL2712 beverage were observed particularly in individuals with chronic inflammation at baseline. The results of this study suggested that heat-killed OLL2712 cells have the potential to improve insulin resistance and glucose metabolism by suppressing chronic inflammation.