Glycemic, Non-esterified Fatty Acid (NEFA) and insulinemic responses to watermelon and apple in type 2 diabetic subjects.

Background – Glycemic Index (GI), Insulin and Non-esterified Fatty Acid (NEFA) responses are useful measures for the biological effects of a carbohydrate diet in relation to diabetes and its complications.

Objective – To determine those indicators in Watermelon and Apple to help in establishing a balanced and better food exchange table for the diabetic patients in Bangladesh. White bread (WB) was used as the reference food.

Design – 13 subjects (8 male and 5 female) under a crossover design, consumed equi-carbohydrate amount of the fruits and bread, with a run-in period of 7 days between the consecutive items. Serum C-peptide was used as the marker of insulin and it was measured by ELISA, HbA(1)c and NEFA were HPLC and Colorimetric methods respectively.

Outcomes – Watermelon and Apple had almost similar glycemic response which were lower than WB and its reflected in their GI values (Apple 94 +/-19, Watermelon 92 +/- 15). Insulin responses were similar in Apple (0.62 +/-1.13) and in Watermelon (0.45 +/- 0.72) and they had a significantly lower Absolute Change (AC) of C-peptide compared to bread (P=0.001 in WB vs Apple and P<0.001 in WB vs Watermelon). There was a lower NEFA response of Watermelon compared with Apple and WB but the difference was not significant.

Conclusions – a) Equi-carbohydrate of Apple, Watermelon and WB produce almost similar glycemic response. The dynamics of blood glucose changes (avoidance of sharp peak) with Apple, however, makes it a better choice compared to the other two. b) Watermelon maintains a glycemic response similar to Apple and WB at the expense of lower insulin response and may have beneficial effect on dyslipidemia.