The role of digestive factors in determining glycemic response in a multiethnic Asian population.

PURPOSE: There are wide inter-individual differences in glycemic response (GR). We aimed to examine key digestive parameters that influence inter-individual and ethnic differences in GR in healthy Asian individuals. METHODS: Seventy-five healthy male subjects (25 Chinese, 25 Malays, and 25 Asian-Indians) were served equivalent available carbohydrate amounts (50 g) of jasmine rice (JR) and basmati rice (BR) on separate occasions. Postprandial blood glucose concentrations were measured at fasting (-5 and 0 min) and at 15- to 30-min interval over 180 min. Mastication parameters (number of chews per mouth and chewing time per mouthful), saliva α-amylase activity, AMY1 gene copy numbers and gastric emptying rate were measured to investigate their relationships with GR. RESULTS: The GR for jasmine rice was significantly higher than for basmati rice (P < 0.001). The median number of AMY1 gene copies was 6, with a range of 2-15. There was a significant positive relationship between AMY1 copy number and α-amylase activity (P = 0.002). There were no significant ethnic differences in GR. For both rice varieties, the number of chews per mouthful was positively associated with the GR (JR, P = 0.011; BR, P = 0.005), while chewing time per mouthful showed a negative association (JR, P = 0.039; BR, P = 0.016). Ethnicity, salivary α-amylase activity, particle size distribution, gastric emptying rate and AMY1 gene copy numbers were not significant contributors to GR (P > 0.05). CONCLUSION: Mastication parameters contribute significantly to GR. Eating slowly and having larger food boluses before swallowing (less chewing), both potentially modifiable, may be beneficial in glycemic control.

Impact of Isotonic Beverage on the Hydration Status of Healthy Chinese Adults in Air-Conditioned Environment.

People living in tropical climates spend much of their time in confined air-conditioned spaces, performing normal daily activities. This study investigated the effect of distilled water (W) or isotonic beverage (IB) on the hydration status in subjects living under these conditions. In a randomized crossover design, forty-nine healthy male subjects either consumed beverage or IB over a period of 8 h (8 h) in a controlled air-conditioned environment. Blood, urine, and saliva samples were collected at baseline and after 8 h. Hydration status was assessed by body mass, urine output, blood and plasma volume, fluid retention, osmolality, electrolyte concentration and salivary flow rate. In the IB group, urine output (1862 ± 86 mL vs. 2104 ± 98 mL) was significantly lower and more fluids were retained (17% ± 3% vs. 7% ± 3%) as compared to W (p < 0.05) after 8 h. IB also resulted in body mass gain (0.14 ± 0.06 kg), while W led to body mass loss (-0.04 ± 0.05 kg) (p = 0.01). A significantly smaller drop in blood volume and lower free water clearance was observed in IB (-1.18% ± 0.43%; 0.55 ± 0.26 mL/min) compared to W (-2.11% ± 0.41%; 1.35 ± 0.24 mL/min) (p < 0.05). IB increased salivary flow rate (0.54 ± 0.05 g/min 0.62 ± 0.04 g/min). In indoor environments, performing routine activities and even without excessive sweating, isotonic beverages may be more effective at retaining fluids and maintaining hydration status by up to 10% compared to distilled water.

Effects of the physical-form and the degree-of-saturation of oil on postprandial plasma triglycerides, glycemia and appetite of healthy Chinese adults.

Ethylcellulose (EC) forms a complex oleogel network that entraps lipids. The digestibility of an oleogel is influenced by the types of oils used in its preparation. This randomised, controlled, crossover study aimed to compare lipidemic, glycemic, and appetitive responses to a test meal alone (no oil control), or to palm oil (PO, 22.25 g), rice bran oil (RBO, 22.25 g), palm oleogel (PG, 22.25 g oil + 2.75 g EC), or rice bran oleogel (RBG, 22.25 g oil + 2.75 g EC). Eighteen healthy Chinese males (age: 28 ± 6 years, weight: 65.9 ± 8.5 kg, and BMI: 21.6 ± 2.0 kg m-2) completed all test visits. The participants consumed a standard dinner and fasted overnight before attending the test session in the following morning. Blood samples were taken before the participants consumed the test meal, and subsequently at fixed intervals. Plasma was analysed for triglycerides, glucose, insulin, and non-esterified fatty acids (NEFA). Appetite sensations were also measured every 30 minutes for 360 minutes. After the test meal consumption, a significant interaction effect (repeated measures ANOVA) was found on temporal changes in triglycerides (p < 0.001). Plasma triglycerides increased significantly in both PO and RBO only, but not in oleogel test meals. PO and RBO also suppressed the rise of glucose (time × treatment effect, p = 0.011) at 20, 30 and 45 min. However, no significant differences were found between palm and rice bran oils in triglycerides and glucose. Changes in insulin, NEFA and appetite did not differ among all treatments. Transformation of oils to oleogels is a novel approach to reduce after-meal triglycerides. This trial was registered with ClinicalTrials.gov as NCT02969057.