Koutnikova H, et al. - In this systematic review and meta-analysis, researchers examined the impact of oral intake of bacterial probiotics [defined as ‘live microorganisms that, when administered in adequate amounts, confer a health benefit on the host’] on 15 variables related to obesity, diabetes and non-alcoholic fatty liver disease. They excluded subjects who had isolated hypercholesterolaemia, alcoholic liver disease, polycystic ovary syndrome and children with an age of <3 years. One hundred and five articles, representing 6826 subjects, met the criteria for inclusion. Probiotics induced improvements in overweight but not obese subjects in body weight, body mass index, waist circumference, body fat mass and visceral adipose tissue mass. Probiotics decreased fasting glucose, glycated haemoglobin, insulin and homeostatic model of insulin resistance in type 2 diabetics. Probiotics decreased alanine and aspartate aminotransferases in subjects with fatty liver diseases. Overall, the investigators concluded that probiotics intake in subjects with metabolic diseases resulted in minor but consistent improvements in several metabolic risk factors.