Absence of a sexual dimorphism in postprandial glucose metabolism after administration of a balanced mixed meal in healthy young volunteers

Abstract

Background/objectives: A different ability to regulate glucose homeostasis between men and women may contribute to their difference in diabetes prevalence and in its predisposing conditions. Data on this issue are controversial because of heterogeneous protocols and insufficient control of confounders affecting glucose metabolism like age, body composition, and physical activity level. To clarify this issue, we compared among sexes the postprandial glucose metabolism after the administration of a balanced mixed meal normalized to daily energy expenditure.

Subjects/methods: Thirty-six healthy young volunteers (18 men and 18 women; age, 23.9 ± 2.8 years; BMI, 21.9 ± 1.7 kg/m²) were recruited for the experiment. After overnight fast, subjects consumed a mixed meal providing 40% of daily energy expenditure (60% carbohydrates, 25% lipids, 15% proteins) estimated multiplying resting energy expenditure, obtained by Harris & Benedict equation, for the corresponding physical activity level. Blood was sampled at 0, 10, 20, 30, 45, 60, 90, 120, and 180 min and serum concentrations of glucose, insulin, and C-peptide were measured.

Results: Fasting serum glucose concentrations were lower in women than in men, while fasting insulin and C-peptide concentrations did not differ between sexes. Linear mixed models did not show any significant effect of sex and sex # time interaction on postprandial serum glucose, insulin, and C-peptide concentrations. The comparison of areas under the curve between the sexes revealed similar glycemic, insulinemic, and C-peptide postprandial responses between men and women.

Conclusions: Our results do not support the hypothesis of a sexual dimorphism in the regulation of carbohydrate metabolism in young when a mixed meal normalized on individual daily energy expenditure is ingested.

Fig. 1. Glucose, insulin, and C-peptide responses to a balanced mixed meal.

Values are serum glucose, insulin and C-peptide concentrations, expressed as mean ± standard error, observed in men and women after consumption of a balanced mixed meal.

Fig. 2. Glucose, insulin, and C-peptide percentage changes in response to a balanced mixed meal.

Values are glucose, insulin, and C-peptide percentage changes from baseline (mean ± standard error) observed in men and women after consumption of a balanced mixed meal.