Gastrointestinal tolerance of erythritol and xylitol ingested in a liquid.

OBJECTIVES: To determine and compare the gastrointestinal (GI) responses of young adults following consumption of 45 g sucrose, 20, 35 and 50 g xylitol or erythritol given as a single oral, bolus dose in a liquid. DESIGN: The study was a randomized, double-blind, placebo-controlled study. SUBJECTS: Seventy healthy adult volunteers aged 18-24 years were recruited from the student population of the University of Salford. Sixty-four subjects completed the study. INTERVENTIONS: Subjects consumed at home without supervision and in random order, either 45 g sucrose or 20, 35 and 50 g erythritol or xylitol in water on individual test days, while maintaining their normal diet. Test days were separated by 7-day washout periods. Subjects reported the prevalence and magnitude of flatulence, borborygmi, bloating, colic, bowel movements and the passage of faeces of an abnormally watery consistency. RESULTS: Compared with 45 g sucrose, consumption of a single oral, bolus dose of 50 g xylitol in water significantly increased the number of subjects reporting nausea (P<0.01), bloating (P<0.05), borborygmi (P<0.005), colic (P<0.05), watery faeces (P<0.05) and total bowel movement frequency (P<0.01). Also 35 g of xylitol increased significantly bowel movement frequency to pass watery faeces (P<0.05). In contrast, 50 g erythritol only significantly increased the number of subjects reporting nausea (P<0.01) and borborygmi (P<0.05). Lower doses of 20 and 35 g erythritol did not provoke a significant increase in GI symptoms. At all levels of intake, xylitol produced significantly more watery faeces than erythritol: resp. 50 g xylitol vs 35 g erythritol (P<0.001), 50 g xylitol vs 20 g erythritol (P<0.001) and 35 g xylitol vs 20 g erythritol (P<0.05). CONCLUSIONS: When consumed in water, 35 and 50 g xylitol was associated with significant intestinal symptom scores and watery faeces, compared to the sucrose control, whereas at all levels studied erythritol scored significantly less symptoms. Consumption of 20 and 35 g erythritol by healthy volunteers, in a liquid, is tolerated well, without any symptoms. At the highest level of erythritol intake (50 g), only a significant increase in borborygmi and nausea was observed, whereas xylitol intake at this level induced a significant increase in watery faeces.

Gastrointestinal responses following acute and medium term intake of retrograded resistant maltodextrins, classified as type 3 resistant starch.

DESIGN: Study part 1 was executed as a randomized double-blind placebo-controlled crossover study and study part 2 as a longitudinal study. SUBJECTS: Forty-one healthy adult volunteers aged 18-24 years were recruited from the student population of the University of Salford. All subjects enrolled and completed study part 1 and 39 subjects enrolled and completed study part 2. INTERVENTIONS: In study part 1, individuals consumed, in random order 0, 20, 40, 60, 80, 100 or 120 g of a RRM containing starch product incorporated in pre-prepared foods on individual test days. Assuming a minimum content of 50% RRM in the starch product this delivered respectively 0, 10, 20, 30, 40, 50 or 60 g of RRM. All foods were prepared and coded by personnel not involved in carrying out the tests. Test days were separated by 7 day washout periods. In study part 2, consumption of RRM was increased from 3.6 g at day 1 in incremental doses up to each subject's MNED as determined in study 1, to be achieved at day 14. Subsequently, RRM intake was from day 15-21 in a way that the final intake at day 21 was at least 10 g above the individual MNED. In both parts of the study, subjects reported the prevalence and magnitude of GI symptoms. RESULTS: No significant change was observed in either defecation frequency and faecal consistency or the number of subjects experiencing any GI symptoms, following consumption of foods containing 0-60 g RRM. The individual MNED at which an increase in symptoms did not occur was determined as 60 g RRM for 71% of the subjects who participated in study part 1. Regression analysis showed that consumption of gradually increasing doses of RRM in food products over 21 days was associated with a significant increase in the mean symptom score for flatulence (P=1.5 x 10(-4)), total bowel movement frequency (P=0.023) and bowel movement frequency to pass watery faeces (P=0.0157). Increasing the ingested dose of RRM by 10 g above the predetermined MNED, however, did not provoke significant increases in GI symptoms. In both studies, the majority of symptom responses were classified by the subjects as 'little more than usual'. CONCLUSIONS: Consumption of up to 60 g RRM is tolerated well by most individuals with no evidence of any significant dose-dependent increase in the magnitude of symptoms or the occurrence of multiple GI symptoms. However, a mild laxative effect when consuming >60 g RRM is suggested. Although there was no change in GI responses following consumption of increasing doses of RRM over 21 days, generally a dose of 10 g RRM above the MNED level was tolerated well during medium term intake.

Short-chain fructo-oligosaccharides reduce the occurrence of colon tumors and develop gut-associated lymphoid tissue in Min mice.

C57BL/6J-Min/+ mice, which are heterozygous for a non-sense mutation in the Apc gene, provide a model for both familial adenomatous polyposis and sporadic colon cancers. In our study, gut tumors and small intestine lymphoid nodules were counted in Min mice fed fiber-enriched diets for 6 weeks. Neither starch-free wheat bran nor resistant starch modified the number of tumors. However, short-chain fructo-oligosaccharides dramatically reduced the incidence of colon tumors and concomitantly developed gut-associated lymphoid tissue. Our experiment shows that short-chain fructo-oligosaccharides counteract advanced stages of colon carcinogenesis, possibly via stimulation of antitumoral immunity by modulation of the colonic ecosystem.

The search for an optimized treatment of hypoglycemia. Carbohydrates in tablets, solutin, or gel for the correction of insulin reactions.

Recommendations for the treatment of insulin reactions are based more on habit than data. We investigated the efficacy in correcting blood glucose levels and alleviating clinical symptoms of hypoglycemia of seven orally administered carbohydrates--glucose in solution, tablets, and gel; sucrose in solution and tablets; a hydrolized polysaccharide solution; and orange juice--each of which provided 15 g of carbohydrate. Forty-one type I diabetic patients recently treated with insulin agreed to submit to artificially induced hypoglycemia by an intravenous injection of insulin. Corrective therapy was given when patients experienced symptoms and asked for treatment. Mean blood glucose levels 10 minutes after ingestion were found to be similar whether correction was dispensed with the tablets and the solutions of glucose, those of sucrose, or the polysaccharide preparation. However, almost no increment was obtained at this time point with the gel or the fruit juice. Fifteen and 20 minutes after carbohydrate intake, blood glucose levels were higher with the tablet forms than with the solutions, although differences only became signifiant for sucrose. Glycemic responses were again consistently lower with the sucrose gel and the orange juice. Clinical symptoms were alleviated in 14.0 +/- 0.8 minutes (mean +/- SEM) with sucrose and glucose in solution or tablets. We conclude that in moderately severe hypoglycemia, ingestion of 15 g of carbohydrate in the form of glucose or sucrose tablets or as a solution provides an effective therapy; both sugars seem equivalent. Even if sucrose lumps are better recommended in terms of cost and availability, they may not be recommendable in terms of palatability. Glucose gel or orange juice cannot be recommended, at least in light of our experimental procedure and at the dosage used therein.

Lack of detectable deleterious effects on metabolic control of daily fructose ingestion for 2 mo in NIDDM patients.

The effects of a daily intake of 30 g fructose on blood glucose regulation, erythrocyte insulin receptors, and lipid metabolism have been studied in type II (non-insulin-dependent) diabetic subjects. Eight well-controlled patients received, in a randomly assigned crossover design over two 2-mo study periods, 30 g of fructose in exchange for an isocaloric amount of starch. Fructose could be taken at any time during the day as part of the 1400-1600 kcal allowed diet (50% carbohydrate, 30% fat, 20% protein). No significant difference was observed concerning body weight, HbA1c, fasting plasma glucose, fasting plasma insulin, uric acid, total cholesterol, high-density lipoprotein cholesterol, and triglycerides, nor was there any change in insulin binding to erythrocytes between the fructose and the control starch period. However, the mean plasma triglyceride levels after the fructose period, although still in the normal range, were significantly higher than baseline values (P less than .05). We conclude that moderate amounts of fructose incorporated into the diet of well-controlled type II diabetic subjects have no significant deleterious effect on glycemic control, insulin receptors of erythrocytes, or lipid metabolism.

Five-week intake of short-chain fructo-oligosaccharides increases intestinal absorption and status of magnesium in postmenopausal women.

Fermentable carbohydrates have been shown to be nondigestible by human enzymes in the small intestine but are fermented extensively in the large bowel to short-chain fatty acids (SCFAs), which can increase mineral absorption. It has been shown that feeding such carbohydrates including short-chain fructo-oligosaccharides (sc-FOSs) increases intestinal magnesium (Mg) absorption in animals, but their beneficial impact on Mg absorption in humans still remains to be established. Therefore, this work aimed to investigate the effect of moderate daily doses of sc-FOSs (10 g/day) on the intestinal absorption and status of Mg in postmenopausal women without hormone replacement therapy (HRT). Eleven healthy postmenopausal women aged 59 +/- 6 years (mean +/- SD) received for 5 weeks sc-FOS or sucrose (placebo) treatments according to a randomized, double-blind, crossover design separated by a washout period of at least 3 weeks. Subjects ingested 87.5 mg of stable isotope 25Mg together with a fecal marker. Subsequently, feces were collected for 5-7 days. An inductively coupled plasma mass spectrometer (ICP/MS) was used for 25Mg stable isotope measurements in feces, urine, and blood. Mg levels were assessed also at the beginning and at the end of each treatment in plasma, erythrocytes, and urine. These measurements allowed for the determination of net intestinal Mg absorption and Mg status. The results show that the addition of 10 g sc-FOS to the diet increased Mg absorption by 12.3%, from 30.2 +/- 5.0% (placebo treatment) to 33.9 +/- 7.2% (sc-FOS treatment; mean +/- SD; p < 0.02). This increase in intestinal Mg absorption was accompanied by an increase in plasma 25Mg level and led to a higher urinary 25Mg excretion. This is the first time that such an effect is shown in humans. The overall conclusion of this work is that the ingestion of moderate doses of sc-FOS did improve intestinal Mg absorption and status in postmenopausal women. Because of the important role of Mg in many cellular functions, such Mg absorption improvement may be particularly interesting when the dietary intake of Mg is limited.

Olive oil phenolics are dose-dependently absorbed in humans.

Olive oil phenolic constituents have been shown, in vitro, to be endowed with potent biological activities including, but not limited to, an antioxidant action. To date, there is no information on the absorption and disposition of such compounds in humans. We report that olive oil phenolics, namely tyrosol and hydroxytyrosol, are dose-dependently absorbed in humans after ingestion and that they are excreted in the urine as glucuronide conjugates. Furthermore, an increase in the dose of phenolics administered increased the proportion of conjugation with glucuronide.

Undigestible sugars in food products.

In the field of sucrose replacement, low-energy bulk ingredients must be used to lower the energy density of food. Ideally, low-energy bulk ingredients as a substitute for sucrose should have significantly less energy, possess physical and chemical properties that precisely match those of sucrose in all food applications, provide secondary health benefits (such as being noncariogenic, being useful for diabetics, and having fiber-like effects), confer no negative side effects, and be completely safe at any amount of consumption. The food industry has developed a range of low-energy bulk ingredients. Most of these are legally permitted in food applications and are undigestible sugars (eg, polyols and fructo-oligosaccharides). Their main nutritional properties (energy value, digestive tolerance, and cariogenicity) are related to their fate in the digestive tract, especially their capacity to be used and fermented by bacteria.

Insulin and glycemic responses in healthy humans to native starches processed in different ways: correlation with in vitro alpha-amylase hydrolysis.

The aim of the study was to elucidate how extracted starches submitted to food processing (or not) can influence plasma insulin and glucose responses in healthy subjects. Native starches from wheat, manihot, smooth peas, or mung beans were tested either raw, as starch gels (boiled and cooled), or cooked and cooled after a preliminary industrial processing: extrusion cooking for wheat, tapioca for manihot, and noodles for mung beans. Eighteen healthy subjects randomly assigned received three different starches under one form of conditioning. All products were submitted to in vitro alpha-amylolysis. Raw manihot starch produced the lowest (p less than 0.05) metabolic responses. Cooking significantly (p less than 0.01) increased plasma responses. However, cooked mung bean noodles gave metabolic responses similar to those of raw products. Close correlations were found between percentages of in vitro starch hydrolysis at 30 min and mean areas under the glycemic curves and the insulinemic curves (r = 0.95, p less than 0.001).

How the degree of unsaturation of dietary fatty acids influences the glucose and insulin responses to different carbohydrates in mixed meals.

The association of fats with carbohydrates results in a lower glucose response but the influence of the nature of the dietary fatty acids has not been investigated clearly. We examined the effect of the degree of dietary fatty acid unsaturation on the postprandial glucose and insulin responses to a mixed meal. Eight young normolipidemic men consumed four different meals in random order. The meals differed in the nature of their oils and in the type of their main carbohydrates. The meals contained either a high ratio of monounsaturated to polyunsaturated n-6 fatty acids (MUFA) or a low ratio (PUFA) and either potatoes or parboiled rice. Proteins and saturated and polyunsaturated n-3 fatty acid contents were not different among meals. Blood samples were collected every 30 min for 3 h after the test meal. The glucose response was significantly lower 30 min after the parboiled rice-PUFA meal than after parboiled rice-MUFA or potato-MUFA (P < 0.05) meals. The insulin response was lower after parboiled rice-PUFA than after potato-MUFA (P < 0.05) meals. Similarly, an effect of fat appeared after 30 min. Glucose responses (F = 1.4, P < 0.01) and insulin responses (F = 5.3, P < 0.05) to both carbohydrates were significantly lower with dietary PUFA compared with dietary MUFA. In conclusion, the degree of dietary fatty acid unsaturation (18:1 compared with 18:2) may influence the glucose and insulin responses to mixed meals.

Role of viscous guar gums in lowering the glycemic response after a solid meal.

The aim of the present study was to investigate how guar gum viscosity acts on starch digestion and glucose absorption in humans. Six healthy subjects received a mixed diet composed of 60.4% carbohydrate in the form of maize glucose or pregelatinized starch, to which was added 5.6% low- or high-viscosity guar gums. Meals were ingested or instilled in the duodenum and postprandial insulin and glucose responses were monitored for 3 h. Infusion of meals containing glucose showed that the delay in the diffusion rate to the duodenal mucosa due to bolus viscosity was not significant. Infusion of meals containing starch showed that a decrease in the digestion rate of starch in the upper small intestine accounted for part of the effect of viscosity on glycemic response, whereas the main effect of guar gum was apparently to slow gastric emptying.

Pasta cooking time: influence on starch digestion and plasma glucose and insulin responses in healthy subjects.

The influence of pasta cooking time on starch digestion and plasma glucose and insulin responses was studied in 12 healthy subjects. During 3 consecutive days, one of three pasta test meals (50 g starch) cooked for 11, 16.5, and 22 min was served to each volunteer in a random order. Hydrogen and methane breath excretion was measured after pasta ingestion; plasma responses were compared with those of an equivalent oral glucose-tolerance test. No significant differences were found between cooking times and plasma indices, orocecal transit time, or incremental hydrogen excretion (delta peak hydrogen). With one exception, pasta meals that were completely absorbed were ingested by methane producers. Postprandial delta peak hydrogen was significantly lower in methane than in nonmethane producers (p less than 0.02). These results point to a lack of influence of cooking time on nutritional characteristics of pasta and suggest that starch malabsorption determined by breath-hydrogen-test criteria may be underestimated in methane producers.

Insulinemic and glycemic indexes of six starch-rich foods taken alone and in a mixed meal by type 2 diabetics.

The glycemic index concept neglects the insulin secretion factor and has not been systematically studied during mixed meals. Six starch-rich foods were tested alone and in an isoglucido-lipido-protidic meal in 18 NIDDs and compared with a glucose challenge. These test meals were randomly assigned using a three factor experiment design. All three tests contained 50 g carbohydrate; mixed meals were adjusted to bring the same amount of fat (20 g), protein (24 g), water (300 mL), and calories (475 kcal) but not the same amount of fiber. Whatever the tested meals, foods elicited a growing glycemic index hierarchy from beans to lentils, rice, spaghetti, potato, and bread (mean range: 0.21 +/- 0.12-92 +/- 0.12, p less than 0.001). Mixing the meals significantly increased the insulinemic indexes (p less than 0.05) and introduced a positive correlation between glycemic and insulinemic indexes (n = 6, r = 0.903; p less than 0.05). The glycemic index concept remains discriminating, even in the context of an iso-glucido-lipido-protidic meal. Insulinemic indexes do not improve discrimination between foods taken alone in type 2 diabetics: they only discriminate between foods during mixed meals, similarly to glycemic indexes.

Digestion, excretion, and energy value of fructooligosaccharides in healthy humans.

The fate of fructooligosaccharides (FOS) in the human gastrointestinal tract was evaluated in six healthy volunteers over an 11-d period. After an equilibration phase, 20.1 g FOS/d was given in three identical postprandial doses. Distal ileal output of FOS and their constituent components were determined by intestinal aspiration after a single meal, and the amounts of FOS excreted in stools and urine were also measured. Most of ingested FOS, 89 +/- 8.3% (mean +/- SEM), was not absorbed in the small intestine, and none was excreted in stools, indicating that the portion reaching the colon was completely fermented by colonic flora. A small fraction of ingested FOS was recovered in urine. The mean estimated energy value of FOS was 9.5 kJ/g. We conclude that in healthy humans, FOS are only slightly digested in the small intestine and then fermented in the colon, resulting in reduced energy production.

Metabolic effects of digestible and partially indigestible cornstarch: a study in the absorptive and postabsorptive periods in healthy humans.

To compare the effects of digestible (pregelatinized) and partially indigestible (retrograded) cornstarches on some metabolic indexes, we studied eight healthy volunteers during two periods separated by 1 wk. In each period, fasting volunteers consumed at 0800 the test meal containing either the digestible or partially indigestible cornstarch; blood and breath were sampled in the absorptive period for 8 h. To study its late effects, the same test meal as that served at 0800 was given again at 2200, and blood and breath were sampled for 3 h in the postabsorptive period the next morning, i.e., 10 h after ingestion of the test meal. In the absorptive period, blood glucose and insulin were significantly higher after ingestion of digestible cornstarch than after partially indigestible cornstarch. In the postabsorptive period concentrations of blood glucose, insulin, and fatty acids were not significantly different, whereas concentrations of blood acetate, breath hydrogen, methane, and 13CO2, and the respiratory quotient and satiety were significantly higher (P < 0.05) and concentrations of blood glycerol significantly lower (P < 0.05) after ingestion of partially indigestible cornstarch than after digestible cornstarch. We conclude that in healthy humans, digestion of partially indigestible cornstarch is slow in the small intestine and its colonic fermentation continues 10-13 h after its ingestion. Compared with pregelatinized cornstarch, the shift in starch digestion induced by retrogradation leads to a reduction in glycemic and insulinemic responses in the absorptive period and in lipolysis in the postabsorptive.

Chronic consumption of short-chain fructooligosaccharides by healthy subjects decreased basal hepatic glucose production but had no effect on insulin-stimulated glucose metabolism.

We aimed to study the effects of chronic ingestion of short-chain fructooligosaccharides (FOS), an indigestible carbohydrate, on hepatic glucose production, insulin-mediated glucose metabolism, erythrocyte insulin binding, and blood lipids in healthy subjects. Twelve healthy volunteers received either 20 g FOS/d or sucrose for 4 wk in a double-blind crossover design. FOS did not modify fasting plasma glucose and insulin concentrations. Mean (+/- SEM) basal hepatic glucose production was lower after FOS than after sucrose consumption (2.18 +/- 0.10 compared with 2.32 +/- 0.09 mg.kg-1, min-1, respectively; P < 0.02, paired Student's t test). However, neither insulin suppression of hepatic glucose production nor insulin stimulation of glucose uptake measured by hyperinsulinemic clamp was significantly different between the two dietary periods. Erythrocyte insulin binding was also comparable. Serum triacylglycerols, total and high-density- lipoprotein cholesterol, apolipoproteins A-I and B, and lipoprotein(a) were not modified by FOS. To try to understand why FOS did not increase serum lipids, the in vitro production of short-chain fatty acids from FOS was evaluated by using human fecal inoculum and compared with that from lactulose, which was found to increase serum lipids. FOS produced an acetate-propionate ratio two times lower than that of lactulose. We conclude that 4 wk of 20 g FOS/d decreased basal hepatic glucose production but had no detectable effect on insulin-stimulated glucose metabolism in healthy subjects. The colonic fermentation pattern of undigestible carbohydrates may be relevant to predicting their metabolic effects.

Euglycemic hyperinsulinemic clamp to assess posthepatic glucose appearance after carbohydrate loading. 1. Validation in pigs.

BACKGROUND: Precise knowledge of the rate of glucose absorption after meal feeding requires invasive methods in humans. OBJECTIVE: This study aimed to validate in an animal model a technique combining the euglycemic hyperinsulinemic clamp and oral carbohydrate loading (OC-Clamp) as a noninvasive procedure to quantify the posthepatic appearance of glucose after oral carbohydrate loading. DESIGN: Twenty-one pigs were fitted with arterial, jugular, portal, and duodenal catheters and a portal blood flow probe. At glucose clamp steady state, duodenal glucose (0.9 g/kg; DG-Clamp) and oral carbohydrate (140 g corn or mung bean starch as part of a mixed meal; OC-Clamp) were administered while the glucose infusion was progressively reduced to compensate for the incremental posthepatic appearance of glucose. [3-3H]glucose was used to assess the glucose turnover rate. RESULTS: Hepatic glucose production was totally suppressed by insulin infusion, and the whole-body glucose turnover rate remained stable during glucose absorption. The incremental portal appearance of glucose after the DG load was not altered by hyperinsulinemia, and the cumulative posthepatic appearance of glucose was 63 +/- 3% (x +/- SEM) of the DG load. The net hepatic portal appearance of glucose remained constant during absorption (34 +/- 3% of the load). After the OC load, the respective portal appearance rates of glucose were significantly different between carbohydrate sources; however, the rates paralleled those of the posthepatic appearance of glucose. Again, net hepatic glucose uptake expressed as portal appearance was similar for both carbohydrates. CONCLUSIONS: The results validate the OC-Clamp method to monitor the posthepatic appearance of glucose after carbohydrate ingestion and to discriminate between different carbohydrate sources. The results suggest that the technique be used in humans.

Satiating effect of proteins in healthy subjects: a comparison of egg albumin, casein, gelatin, soy protein, pea protein, and wheat gluten.

The influence of six dietary protein types (egg albumin, casein, gelatin, soy protein, pea protein, and wheat gluten) on satiety and food intake was investigated. Twelve healthy subjects ingested six protein-manipulated lunches (approximately 5.2 MJ, 22% of energy as protein) according to a within-subjects design. Test meals were controlled for energy, macronutrients, fiber, and palatability. Nearly 65% of total protein varied between sessions. After lunch, satiety was assessed for 8 h and energy and macronutrients intakes were measured for 24 h. Blood was collected for determination of postprandial plasma glucose and insulin responses. Results showed no effect of the type of protein on satiety, on 24-h energy or macronutrient intakes, or on postprandial plasma glucose and insulin concentrations. These findings differ in part from those obtained previously in humans, which suggested that proteins may be differentiated in terms of their satiating capacities. We conclude that varying the protein source in a mixed meal does not affect food behavior in healthy humans, probably because coingestion of carbohydrate and fat with protein buffers the kinetics of the physiologic mechanisms implicated in postprandial satiety after a protein load.

Small-intestinal digestion of partially resistant cornstarch in healthy subjects.

The aims of this study were to measure the amount of starch from partially resistant starches (retrograded and complexed high-amylose cornstarches) escaping small-intestinal digestion in healthy humans by use of an intubation method and to compare these data with data obtained by indirect in vitro methods. Experiments were carried out in vivo in 6 healthy humans by using ileal intubation and stool analysis and in vitro by using 3 different methods for analyzing resistant starch. In intubated subjects, 51 +/- 2% of the retrograded and 21 +/- 2% of the complexed starch was delivered to the ileum and was fermented almost completely in the colon. In vitro estimates of the absorption of resistant starch were much lower. We conclude that technologically modified starches may substantially increase the amount of carbohydrate available for colonic fermentation in humans, but that in vitro measurements of resistant starch are inaccurate for predicting malabsorption in healthy humans.

Euglycemic hyperinsulinemic clamp to assess posthepatic glucose appearance after carbohydrate loading. 2. Evaluation of corn and mung bean starches in healthy men.

BACKGROUND: The rate of absorption of glucose from carbohydrates is important in several aspects of health. We recently validated a noninvasive technique in pigs, euglycemic hyperinsulinemic clamp plus oral carbohydrate loading (OC-Clamp), to quantify the rate of net posthepatic appearance of glucose after ingestion of carbohydrates. OBJECTIVE: The OC-Clamp procedure was performed in 8 healthy men to compare the net posthepatic appearance of glucose after ingestion of 1 of 3 carbohydrates. DESIGN: Human volunteers underwent the OC-Clamp procedure at an insulin infusion rate of 1.5 mU x kg(-1) x min(-1) (n = 5). The oral carbohydrate load (1 g/kg) consisted of glucose, cornstarch, or mung bean starch. During the OC-Clamp procedure, the glucose infusion rate decreased during absorption to maintain plasma glucose steady state and the decrease reflected the net posthepatic appearance of glucose. In addition, carbohydrates were loaded without insulin infusion (n = 6) and glycemic indexes were calculated (with glucose as the reference). RESULTS: The mean (+/-SEM) glycemic index of cornstarch was higher (95 +/- 18) than that of mung bean starch (51 +/- 13). In the OC-Clamp experiments, the posthepatic appearance of glucose and cornstarch did not differ significantly and represented 79.4 +/- 5.0% and 72.6 +/- 4.0%, respectively, of the load after complete absorption (within 3 h). In contrast, the net posthepatic appearance of glucose from mung bean starch was significantly lower (35.6 +/- 4.6% of the load, P < 0.001) than that from glucose and cornstarch, even 4.5 h postprandially. CONCLUSIONS: The OC-Clamp technique allows a continuous assessment of net posthepatic appearance of glucose after ingestion of carbohydrates and significant discrimination between corn and mung bean starches.