Effect of neutralized and native vinegar on blood glucose and acetate responses to a mixed meal in healthy subjects

OBJECTIVE: To investigate the influence of sodium acetate and acetic acid from vinegar on blood glucose and acetate response to a mixed meal in healthy subjects. DESIGN: Five healthy subjects consumed in random order six test meals consisting of 100 g of sliced lettuce dressed with olive oil (Blank), olive oil plus 1 g acetic acid in the form of vinegar (AcOH), or olive oil plus sodium acetate in the form of vinegar neutralized to pH 6.0 with sodium bicarbonate (AcNa). On three occasions test meals were followed by a challenge consisting of 50 g carbohydrate portions of white bread (Bread). Glucose and acetate concentrations were measured in arterialized capillary blood before and until 95 min after the meals. Ultrasonography was performed in four other subjects to measure gastric emptying times after AcOH + Bread and AcNa + Bread. RESULTS: Blood acetate response over 95 min was markedly reduced after AcOH and AcOH+Bread meals compared to AcNa and AcNa + Bread. Similarly, the glucose response was depressed by 31.4% (P = 0.0228) after AcOH+Bread with respect to AcNa + Bread and Blank + Bread. No difference was observed between gastric emptying times after AcOH + Bread and AcNa + Bread. CONCLUSIONS: The results suggest that oral acetic acid and acetate might have a different effect on acetataemia and that a limited dose of vinegar, in the form of salad dressing, is sufficient to influence significantly the glycaemic response to a mixed meal in normal subjects by a mechanism related to acidity but not to gastric emptying