Vinegar reduces postprandial hyperglycaemia in patients with type II diabetes when added to a high, but not to a low, glycaemic index meal

Abstract

Earlier studies have shown that the addition of vinegar in a carbohydrate-rich meal lowers glucose and insulin response in healthy individuals. The mechanism of how this is accomplished, however, remains unclear. The aim of this study is to examine the effect of vinegar on glucose and insulin response in patients with type II diabetes (T2D) in relation to the type of carbohydrates consumed in a meal. Sixteen patients with T2D were divided into two groups, matched for age, gender and HbA(1c). Patients in the first group (group A) were given a high-glycaemic index (GI) meal (mashed potatoes and low-fat milk) on two different days, with and without the addition of vinegar, respectively. In the second group (group B), patients were given an isocaloric meal with the same nutrient composition, but low GI (whole grain bread, lettuce and low-fat cheese). Postprandial plasma glucose and insulin values were measured every 30 min for 2 h. In group A, the incremental area under the curve of glucose (GiAUC(120)) was lower after the addition of vinegar (181+/-78 mmol min/l vs 311+/-124 mmol min/l, P=0.04). The iAUC of insulin (IiAUC(120)) was also reduced, but the difference was of marginal statistical significance (2368+/-1061 microU min/ml vs 3545+/-2586 microU min/ml, P=0.056). In group B, the addition of vinegar did not affect either the GiAUC(120) (229+/-38 mmol min/l vs 238+/-25 mmol min/l, P=0.56) or the IiAUC(120) (2996+/-1302 microU min/ml vs 3007+/-1255 microU min/ml, P=0.98). We conclude that the addition of vinegar reduces postprandial glycaemia in patients with T2D only when it is added to a high-GI meal.