Wine, beer, metabolic syndrome

Several studies exploring the relationship between alcohol consumption and metabolic syndrome have raised ambiguous data. The few experimental trials do not support the hypothesis of an association between moderate alcohol consumption and improvement of insulin sensitivity. Transversal epidemiologic studies show a positive relation between alcohol intake and increase of triglycerides, blood pressure and HDL cholesterol. The effects on body weight, adiposity, glycemia and insulinemia are conflicting. Possible explanations for inconsistencies in findings include differences in drinking patterns and populations studied. Cohort studies investigating the relationship between alcohol intake and incidence of type 2 diabetes are also inconclusive. Some authors describe a J-shape relationship, the moderate consumption group bearing the lowest risk. Positive associations, with the lowest risk among abstainers, and inverse associations, with the lower risk situated in the top alcohol consumption category, are also recorded. There is no clear demonstration of a positive influence of specific beverage choice, such as wine or beer, on insulin sensitivity, metabolic syndrome components or associated biologic markers. The impossibility to completely control confounders or to conduct long-term randomized controlled clinical trials makes caution necessary in interpretation of observational studies and advice provided to patients.