Title
Fructans of chicory: intestinal transport and fermentation of different chain lengths and relation to fructose and sorbitol malabsorption.
Author
Rumessen JJ; Gudmand H¦yer E
Source
Am J Clin Nutr, 1998 Aug, 68:2, 357-64
Abstract
Fructans (fructooligosaccharides and inulin) are of increasing interest to clinical nutritionists as functional food additives. The chemically closely related food carbohydrates fructose and sorbitol are implicated in functional bowel disease.Intestinal handling of these carbohydrates is incompletely understood. Intestinal absorption, transit, and fermentation (breath hydrogen and methane, venous acetate, blood glucose, and urine fructans) after ingestion of 10-30 g short- and long-chain fructans from chicory were studied by single-blind, crossover randomization in 10 healthy adults. Responses were compared with responses after ingestion of lactulose, fructose, and sorbitol. Breath hydrogen and venous acetate production increased in proportion to increasing fructan dose and were similar to responses to lactulose. The transit times of long-chain fructans were longer than those of short-chain fructans (75 compared with 30 min, P<0.001). Semiquantitative estimates of unabsorbed carbohydrate were not significantly different with either short-chain fructans or lactulose as nonabsorbable standards. Venous acetate curves were less precise estimates of the magnitude of carbohydrate malabsorption than were breath-hydrogen curves (P<0.01). All subjects showed malabsorption of 50 g fructose, resulting in significantly more symptoms than 20 g fructose (P<0.05). Ingestion of sorbitol with equimolar amounts of glucose did not reduce malabsorption or abdominal distress. Abdominal symptoms after fructans increased with increasing dose and decreasing chain length. The overall gastrointestinal effects of short-chain fructans seem similar to those of lactulose. Fructans with different chain lengths may have different physiologic properties and further studies of fructans in disease states are warranted.

Title
Nondigestible oligosaccharides do not interfere with calcium and nonheme-iron absorption in young, healthy men.
Author
van den Heuvel EG; Schaafsma G; Muys T; van Dokkum W
Source
Am J Clin Nutr, 1998 Mar, 67:3, 445-51
Abstract
The effect of inulin, fructooligosaccharides, and galactooligosaccharides on true intestinal absorption of iron and calcium was measured in men by using double stable-isotope techniques (oral 57Fe and 44Ca and intravenous 58Fe and 48Ca). The incorporation of iron isotopes into erythrocytes and the urinary excretion of calcium isotopes was measured with an inductively coupled plasma mass spectrometer. Twelve healthy, nonanemic, male subjects aged 20-30 y received four treatments consisting of a constant basal diet supplemented with 15 g/d inulin, fructooligosaccharide, or galactooligosaccharide, or not supplemented (control treatment). These four treatments were given for 21 d each according to a randomized, crossover design. Iron absorption was measured over the last 7 d of treatment (days 15-21) and calcium absorption was measured on day 21 of each treatment period. Mean (+/- SEM) iron absorption was 5.5 +/- 1.6%, 6.1 +/- 1.9%, 5.3 +/- 1.9%, and 5.1 +/- 1.5%, respectively, during treatment with inulin, fructooligosaccharide, galactooligosaccharide, or the control; mean ( SEM) calcium absorption was 25.8 +/- 2.3%, 26.3 +/- 1.9%, 26.3 +/- 2.6%, and 28.1 +/- 4.3%, respectively. None of the differences between treatments was significant. It is concluded that 15 g/d inulin, fructooligosaccharide, or galactooligosaccharide did not have a negative effect on iron and calcium absorption in young healthy men.

Title
In vivo absorption of calcium carbonate and magnesium oxide from the large intestine in rats. Author
Ohta A; Baba S; Ohtsuki M; Takizawa T; Adachi T; Hara H
Source
J Nutr Sci Vitaminol (Tokyo), 1997 Feb, 43:1, 35-46
Abstract
This study was conducted to evaluate the ability of the large intestine to absorb calcium (Ca) and magnesium (Mg) from their sparingly water-soluble salts, and also to determine whether fructooligosaccharides (FOS) stimulate the absorption of these minerals in rat large intestine in vivo. Rats were fed Ca- and Mg-free diets with and without 5% FOS. An aqueous suspension of CaCO3 and MgO was infused into the stomach via a gastric tube or into the cecum via an implanted catheter. Coprophagy was prevented by using wire-mesh anal cups throughout the experiment so as to exclude the re-ingestion of feces as an oral mineral Source. In rats fed an FOS-free diet, the absorption degrees of Ca and Mg infused into the cecum were the same as those infused into the stomach. The absorption degree of phosphorus (P) was slightly but significantly higher in rats with the infusion of Ca and Mg into the cecum than in rats with the infusion of Ca and Mg into the stomach. FOS-feeding increased the absorption of Mg to a similar extent in either case of infusion via cecal and oral routes, while FOS-feeding did not increase the absorption of Ca in rats with infusion of Ca and Mg into the cecum. We concluded that both CaCO3 and MgO are absorbed in the large intestine, and we ascertained that the increasing effect of FOS on the absorption of Mg took place mainly in the large intestine.

Title
Selected indigestible oligosaccharides affect large bowel mass, cecal and fecal short-chain fatty acids, pH and microflora in rats.
Author
Campbell JM; Fahey GC Jr; Wolf BW
Source
J Nutr, 1997 Jan, 127:1, 130-6
Abstract
Certain indigestible oligosaccharides may benefit gastrointestinal tract health via fermentation and proliferation of desirable bacterial species. The purpose of this study was to elucidate effects of selected oligosaccharides on cecal and fecal short-chain fatty acid (SCFA) concentration, pH, total large bowel wet weight and wall weight, and gut microbiota levels in rats. Fifty male Sprague-Dawley rats were randomly assigned to one of five treatments: 1) control diet; 2) control diet + 5% microcrystalline cellulose (5% CC); 3) control diet + 5% CC + 6% fructooligosaccharides; 4) control diet + 5% CC + 6% oligofructose; or 5) control diet + 5% CC + 6% xylooligosaccharides. The control diet consisted of (dry matter basis) 20% protein, 65% carbohydrate, 10.5% fat, vitamin and mineral mixes. The duration of the study was 14 d. The oligofructose- and fructooligosaccharide-containing diets resulted in higher cecal butyrate concentrations compared with the control, cellulose and xylooligosaccharide diets. Generally, total cecal SCFA pools were higher while pH was lower from ingesting oligosaccharide-containing diets compared with control or cellulose diets. Cecal total weight and wall weight were higher from oligosaccharide consumption, whereas colonic total wet weight was higher for rats consuming xylooligosaccharides compared with other treatments; colon wall weight was unaffected by treatments. Cecal bifidobacteria and total anaerobes were higher whereas total aerobes were lower in rats fed oligosaccharide diets compared with those fed the control diet. Cecal lactobacilli levels were unaffected by treatment. Dietary incorporation of fermentable, indigestible oligosaccharides, by providing SCFA, lowering pH, and increasing bifidobacteria, may be beneficial in improving gastrointestinal health.