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Objective: To study the in¯uence of parboiling and the severity of the process on glycaemic and insulinaemic responses to rice in type 2 diabetes. Moreover, to examine changes in starch structure related to parboiling, which may affect the metabolic responses and digestibility. Design: Nine type 2 diabetic subjects ingested four test meals: white bread (WB) and three meals of cooked polished rice of the same variety being non-parboiled (NP), mildly traditionally parboiled (TP) and severely pressure parboiled (PP). The participants ingested the test meals (50 g available carbohydrates) on separate occasions after an overnight fast. Setting: Outpatient clinic, Dept. Endocrinology and Metabolism, Aarhus University Hospital, Denmark. Results: All three rice samples elicited lower postprandial plasma glucose response (NP: 335 AE 43; TP: 274AE 53; PP: 231 AE 37 mmola1*180 min.; means AE s.e.m.) than white bread (626 AE 80; P`0.001), within rice samples PP tended to be lower than NP (P 0.07). The glycaemic indices were: NP: 55 AE 5, TP: 46 AE 8 and PP: 39 AE 6, and lower for PP than NP (P`0.05). The insulin responses were similar for the three rice meals, which were all lower than that to white bread (P`0.001). Differential scanning calorimetry showed the presence of amylose ± lipid complexes in all rice samples and of retrograded amylopectin in PP. Amylose retrogradation was not detected in any of the rice samples. Conclusions: All rice test meals were low-glycaemic in type 2 diabetic subjects. There was no effect of TP on glycaemic index, whereas PP reduced the glycaemic index by almost 30% compared to NP.

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The aim of the present study was to elucidate whether the qualitative composition of dietary fat influences plasma leptin and adipose tissue ob gene expression differentially. Two high-fat diets and a diet rich in carbohydrate were each administered both ad libitum and with a 25% energy restriction. The high-fat diets contained 58 energy percent as either monounsaturated FA (MUFA) or saturated FA (SAFA), whereas the carbohydrate-rich diet (CH) contained 7 energy percent as fat. We aimed at obtaining the same final weight for the animals in the ad libitum group as in the energy-restricted groups. This goal was reached at the same time (days 22-24) for all groups except for the ad libitum animals fed on saturated fat (day 36). The plasma leptin concentrations on ad libitum CH and MUFA diets did not differ significantly (24.3 +/- 2.1 and 34.7 +/- 6.7 ng/mL, respectively) whereas the saturated fat diet caused a lower concentration (13.9 +/- 1.9 ng/mL; P < 0.05). Interestingly, no differences in plasma leptin levels between groups were seen in the energy-restricted groups (mean 8.0 +/- 1.0 ng/mL). The type of diet did not alter the ob gene expression in intraabdominal white adipose tissue; however, a lower expression level was found in the energy-restricted groups. The percentage of body fat in the three ad libitum fed groups did not differ (23 +/- 1%). Thus, short-term administration of a diet rich in SAFA suppresses circulating leptin levels without altering the adipose tissue ob gene expression. This indicates that saturated fat may alter protein handling by adipose tissue or the whole body clearance of leptin.