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Background: Starch composition and rate of digestion are determinants of blood glucose concentrations and food intake (FI)., Objective: Our objective was to describe relations between estimates of digestibility of starches by the in vitro Englyst method and their effect on blood glucose concentrations, subjective appetite, and FI in young men., Design: Subjects consumed 5 soups containing 50 g maltodextrin, whole-grain, high-amylose, regular cornstarch, or no added starch at 1-wk intervals. Ad libitum FI was measured at 30 min (experiment 1) or 120 min (experiment 2) later, which were the estimated times of digestion of a rapidly digestible starch (RDS) and slowly digestible starch, respectively. Blood glucose concentrations and appetite were measured pre- and postmeal., Results: At 30 min, FI was reduced by maltodextrin only [86% RDS, 12% resistant starch (RS); P < 0.05], but at 120 min FI was reduced by whole-grain (24% RDS, 66% RS), high-amylose corn (40% RDS, 48% RS), and regular corn (27% RDS, 39% RS) (P < 0.0001). The premeal blood glucose concentration at 30 and 120 min was highest and lowest after maltodextrin treatment, respectively (P < 0.0001). After the meal, the blood glucose area under the curve at 30 min was lower after all starch treatments (P < 0.05), but at 120 min the blood glucose area under the curve was lower only after the regular cornstarch treatment (P < 0.05). Premeal appetite decreased by all treatments (P < 0.05)., Conclusion: The in vitro estimates of starch digestibility by the Englyst method predicted the effects of starch composition on blood glucose concentrations and FI in young men 30 and 120 min after consumption. This trial was registered at clinicaltrials.gov as NCT00980941 for experiment 1 and NCT00988689 for experiment 2.

Two experiments were conducted to determine the effect of nonwaxy (amylose and amylopectin starch) or waxy (amylopectin starch) sorghum on growth, carcass traits, and glucose and insulin kinetics of pigs. In Exp. 1 (95-d), 60 crossbred barrows or gilts (initial and final BW of 24 and 104 kg) were allotted to three treatments with five replications of four pigs per replicate pen in a randomized complete block design. The dietary treatments for Exp. 1 were 1) corn-soybean meal (C-SBM) diet, 2) sorghum-SBM (red pericarp, non-waxy), and 3) sorghum-SBM (red pericarp, waxy). In Exp. 2, 28 crossbred barrows (initial and final BW of 24 and 64 kg) were allotted to two treatments with three replications of four or five pigs per replicate pen in a randomized complete block design. Growth data were collected for 49 d, and then 20 barrows were fitted with jugular catheters, and then a glucose tolerance test (500 mg glucose/kg BW), an insulin challenge test (0.1 IU of porcine insulin/kg BW), and a feeding challenge were conducted. The dietary treatments for Exp. 2 were 1) sorghum-SBM (white pericarp, nonwaxy) and 2) sorghum-SBM (white pericarp, waxy). In Exp. 1, ADG (P = 0.10) and ADFI (as-fed basis; P = 0.02) were increased (P = 0.10) and gain:feed was decreased (P = 0.04) in pigs fed the sorghum-SBM diets relative to those fed the C-SBM diet. These responses may have resulted from the lower energy content of sorghum relative to corn. Plasma NEFA concentration (collected after a 16-h fast on d 77) was decreased (P = 0.08) in pigs fed the waxy sorghum-SBM diet relative to those fed the nonwaxy sorghum-SBM diet. Kilograms of carcass fat was decreased (P = 0.07) in pigs fed the waxy sorghum-SBM diet relative to those fed the nonwaxy sorghum-SBM diet. In Exp. 2, there was no effect (P = 0.57 to 0.93) of sorghum starch type on growth performance by pigs. During the glucose tolerance and insulin challenge tests, there were no effects (P = 0.16 to 0.98) of diet on glucose or insulin kinetics. During the feeding challenge, glucose (P = 0.02) and plasma urea N (P = 0.06) area under the response curves from 0 to 90 min were decreased in pigs fed the waxy sorghum-SBM diet. Feeding waxy sorghum had minimal effects on growth and carcass traits relative to pigs fed corn or nonwaxy sorghum. Waxy sorghum vs. nonwaxy sorghum had no effect on glucose or insulin kinetics in pigs.

Objective: Consumption of a meal high in amylose starch (70%) decreases peak insulin and glucose levels and area under the curve (AUC). The objective was to determine the amount of amylose necessary in a meal for the beneficial decrease in glucose or insulin to occur., Design: Twenty-five subjects, 13 men (averaging 88.1 kg, 41 y, and 27.9 body mass index) and 12 women (averaging 72.4 kg, 41 y and 27.1 body mass index) were given six tolerance tests in a Latin Square design: glucose alone (1 g glucose/kg body weight) and five breads (1 g carbohydrate/kg body weight) made with 70% amylose cornstarch, standard cornstarch (30% amylose), and blends of the two starches (40, 50 and 60% amylose starch). A standard menu was fed for 3 days. One subject withdrew from the study., Results: Glucose, insulin and glucagon response to the carbohydrate loads was similar in men and women. Peak glucose response was lowest after the breads containing 50-70% amylose starch. AUC was significantly higher after the glucose load than after all bread loads. The lowest AUCs occurred after the 60 and 70% amylose starch breads. Insulin response and AUC were significantly lower after the 60 and 70% amylose starch breads than after the glucose or the other breads., Conclusion: Results indicate that the amylose content of the starch used in the acute meal needs to be greater than 50% to significantly reduce plasma glucose and insulin in men and women.

Objective: To study the effect of amylose content on postprandial glucose and insulin responses in healthy subjects by serving fixed amounts of simple starchy foods with a varying but strictly controlled water, fat and guar gum content., Design: A blind, randomised, balanced cross-over study., Setting: The kitchen of the Nutrition Research Unit in the Unilever Research Laboratorium., Subjects: Apparently healthy employees of Unilever Research Laboratorium., Interventions: Subjects consumed, after an overnight fast, either a drink (12 men), a pudding (6 men and 6 women), a roll without (5 men and 6 women) or a roll with guar gum (12 men) as breakfast and the same amount of the same food as mid-morning snack. Each subject consumed the experimental food prepared in four ways: either with high- or normal-amylose starch, and with or without added fat. At 30 and 90 min after consumption of the breakfast or the snack a blood sample was taken for determination of glucose and insulin., Results: Raising the amount of amylose in starchy drinks and puddings, but not in rolls, lowered postprandial glucose and insulin responses. Fat addition to starchy drinks, puddings and rolls attenuated postprandial glucose responses, irrespective of the amount of amylose or guar gum present. Addition of guar gum to rolls reduced glucose and insulin responses. Glucose tolerance tended to be less after consumption of the experimental foods as mid-morning snack than after consumption as breakfast., Conclusion: The physico-chemical composition of foods does influence the effect of the amylose:amylopectin ratio in starchy foods on postprandial glucose and insulin responses.

Twelve women and 13 men were given meals containing cornstarch with 70% of the starch in the form of amylopectin or amylose to determine if differences in glycemic response result from different chemical structure. Blood was drawn before and 30, 60, 120, and 180 min after each meal. The meals consisted of starch crackers fed at the rate of 1 g carbohydrate from starch per kilogram body weight. The amylose meal resulted in a significantly lower glucose peak at 30 min than did the amylopectin meal. Plasma insulin response was significantly lower 30 and 60 min after amylose than after the amylopectin meal. Summed insulin above fasting was significantly lower after amylose while summed glucose was not significantly different between the two meals. The sustained plasma glucose levels after the amylose meal with reduced insulin requirement suggest amylose starch may be of potential benefit to carbohydrate-sensitive or diabetic individuals.

We evaluated the effect of amylose and amylopectin content on the glucose and insulin responses to rice. Thirty-three normal volunteers were given three types of rice containing 0, 14 to 17, or 23 to 25% of carbohydrate in the form of amylose. The glucose and insulin responses were measured over a period of 180 min. Serum glucose response to high amylose rice was significantly lower at 30 min, and dropped more gradually by 180 min than with 0% amylose rice. In addition, the high amylose rice produced significantly lower insulin levels at 30 and 60 min, as well as lower integrated secretion over the 3-h test. Thus, our results suggest the presence of a factor in high-amylose rice which delays digestion and/or absorption of carbohydrate. Since fiber content and surface area of the test rices were identical, other factors must underlie these observed differences. These include differential enzymatic hydrolysis of amylose and amylopectin and the presence of lipid-starch complexes in the amylose-containing rice.