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Background: An enhancing effect of short-chain fructooligosaccharities (scFOSs) on intestinal calcium absorption has been shown in animals and in some short-term human studies. However, the long-term effect of scFOSs on calcium absorption in humans is still unknown. Objective: We investigated the long-term effect of a moderate daily dose (10 g) of scFOSs on intestinal calcium absorption in postmenopausal women. Design: In a randomized, double-blind crossover protocol, 12 healthy, postmenopausal women received scFOSs or placebo for 5 wk. The treatments were separated by a 3-wk washout period. Subjects orally received [44.sup]Ca (stable isotope) and a fecal marker. Feces were collected after the isotope intake for 5-7 d to measure unabsorbed isotope. Calcium-status indexes, calciotropic hormones, and bone turnover were also assessed. Results: Mean ([+ or -] SD) intestinal calcium absorption with scFOS treatment was not significantly different from that with placebo treatment (35.63 [+ or -] 9.40% and 36.55 [+ or -] 8.48%, respectively). However, a tendency for calcium absorption to be higher with scFOS treatment than with placebo treatment was observed in women who had been going through menopause for > 6 y. Conclusions: scFOSs do not modify intestinal calcium absorption in postmenopausal women who do not receive hormonal replacement therapy. The results from a subgroup of women who had been going through menopause for > 6 y (n = 6) suggest that scFOSs may influence calcium absorption in the late postmenopausal phase. The small number of subjects and the related P value warrant verification and further investigation with women in late menopause only. KEY WORDS Short-chain fructooligosaccharides, fermentation, intestinal absorption, calcium, stable isotopes, postmenopausal women, bone turnover, [44.sup]Ca

Background: The rate of absorption of glucose from carbohydrates is important in several aspects of health. We recently validated a non-invasive 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 [multiplied by] [kg.sup.-1] [multiplied by] [min.sup.-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 ([+ or -] SEM) glycemic index of cornstarch was higher (95 [+ or -] 18) than that of mung bean starch (51 [+ or -] 13). In the OC-Clamp experiments, the posthepatic appearance of glucose and cornstarch did not differ significantly and represented 79.4 [+ or -] 5.0% and 72.6 [+ or -] 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 [+ or -] 4.6% of the load, P [is less than] 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. Am J Clin Nutr 1999;69:1183-8.

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-[sup.3]H]]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 [+ or -] 3% ([bar]x [+ or -] SEM) of the DG load. The net hepatic portal appearance of glucose remained constant during absorption (34 [+ or -] 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. Am J Clin Nutr 1999;69:1174-82.