## 4 Discussion  
In the present study, we observed that apple consumption before meals (the apple-first group) did not exhibit any significant difference in blood glucose and insulin levels when compared with the rice-first group in normal subjects. However, consuming apples first showed a slower increase in the post-prandial blood glucose for the subjects with impaired glucose tolerance. [PERSON] et al. reported that people who frequently are apples tended to have less of a postprandial increase in blood glucose and longer-lasting satiety [23]. Interestingly, those who regularly exercise and ate apples as part of their daily routine had the lowest postprandial increase in blood glucose levels. Apples contain soluble dietary fiber (pectin) [26], fructose [27], and alpha-glucosidase inhibitors [28]. Soluble dietary fiber is not easily digested and swells in the stomach, increasing the viscosity of the stomach contents and prolonging the residence time in the stomach, thereby delaying the sugar absorption [29]. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Glucose Level** & **\(\Delta\)Cmax** & **Tmax** & **iAUC** \\  & **(mg/dL)** & **(min)** & **(mg-min/dL)** \\ \hline Rice-first group & 54.0 \(\pm\) 5.0 & 33.0 \(\pm\) 2.0 & 3666 \(\pm\) 458 \\ \hline Apple-first group & 46.2 \(\pm\) 5.9 & 54.0 \(\pm\) 12.7 & 3952 \(\pm\) 652 \\ \hline
**Insulin Level** & **\(\Delta\)Cmax** & **Tmax** & **iAUC** \\  & **(μ/dL)** & **(min)** & **(μU-min/dL)** \\ \hline Rice-first group & 61.9 \(\pm\) 7.2 & 31.3 \(\pm\) 4.2 & 4452 \(\pm\) 878 \\ \hline Apple-first group & 49.8 \(\pm\) 8.5 & 45.0 \(\pm\) 9.2 & 3669 \(\pm\) 916 \\ \hline \hline \end{tabular} Mean \(\pm\) SEM, \(n=10\). No significant difference was noted between groups.  
\end{table} 
Table 2: Dynamic parameters of blood glucose and insulin levels in the normal subjects. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Glucose Level** & **\(\Delta\)Cmax** & **Tmax** & **iAUC** \\  & **(mg/dL)** & **(min)** & **(mg-min/dL)** \\ \hline Rice-first group & 90.0 \(\pm\) 10.0 & 48.3 \(\pm\) 6.5 & 7739 \(\pm\) 1474 \\ Apple-first group & 75.2 \(\pm\) 7.2 * & 55.0 \(\pm\) 9.0 & 6481 \(\pm\) 1105 \\ \hline iAUC, incremental area under the curve. Mean \(\pm\) SEM, \(n=10\). * \(p<0.05\): rice-first versus apple-first group.  
\end{table} 
Table 3: Dynamic parameters of blood glucose levels in the impaired glucose tolerance subjects. Carbohydrates are ingested and absorbed from the intestinal tract and transported through the portal vein, first to the liver and then to the rest of the body. Carbohydrates in the body are supplied to the various tissues as a source of energy and then stored as glycogen in the liver and muscles. Fructose, a monosaccharide, is incorporated into the metabolism of glucose (glycolysis) but follows a different pathway in the muscles and liver. Fructose is converted to triglycerides in the liver, which can increase very low-density lipoproteins, leading to hyperlipidemia. However, most of the metabolism of fructose reportedly occurs in the cells of the small intestine, where it is first phosphorylated by ketoexokinase and then passed downstream [30]. In the present study, the Tmax value of blood glucose was prolonged in the group that consumed apples first, regardless of whether they had impaired glucose tolerance. Other possible effects on blood glucose levels may be due to pectin, a type of dietary fibre found in apples [26]. In addition, the prolongation of Tmax was more pronounced in those with impaired glucose tolerance than in those with normal glucose tolerance, possibly due to a slower cellular uptake of glucose. The blood glucose Cmax levels in both subject groups were reduced by the pre-meal consumption of apples (the apple-first group). These results may be due to the inhibition of glucose and, hence, the carbohydrate digestion and absorption processes by alpha-glucosidase inhibitors and polyphenols.