Constipation is an ailment encountered often in elderly people. A study was initiated to test the effects of lactose or inulin on the bowel habits of constipated elderly patients and to correlate these effects with several variables measured in feces such as microflora composition, concentration of lactate and short-chain fatty acids (SCFAs), pH, and the activities of beta-glucosidase and beta-glucuronidase, Groups of 15 and 10 patients received lactose and inulin, respectively, for a period of 19 d. The dose, 20 g/d from days 1 to 8, was gradually increased to 40 g/d from days 9 to 11 and was kept at this dose from days 12 to 19. There was considerable interindividual variations with this kind of dietary intervention. Inulin increased bifidobacteria significantly from 7.9 to 9.2 log10/g dry feces, but decreased enterococci in number and enterobacteria in frequency. In individuals consuming lactose, a noticeable increase in fecal counts of enterococci and a decrease in lactobacilli and clostridia was detected. Total bacterial counts remained unchanged. No changes in the concentrations of fecal SCFAs and lactate were observed. SCFAs showed a slight trend toward higher molar ratios of acetate to butyrate in response to the intake of lactose or inulin. The fecal pH and the beta-glucosidase and beta-glucuronidase activities were not influenced by sugar intake. Inulin showed a better laxative effect than lactose and reduced functional constipation with only mild discomfort.

Pathogenic events in CD and UC may be associated with different alterations in the mucosal flora of the ileum and colon.

Dietary incorporation of fermentable, indigestible fructans may be of benefit to gastrointestinal health by providing short-chain fatty acids, stimulating the proliferation of bifidobacteria or lactobacilli and suppressing potential pathogenic organisms in the gut. We tested the hypothesis that the effects of fructans on caecal, colonic and faecal short-chain fatty acid concentration and microflora composition depend on their chain length. Germ-free rats associated with a human faecal flora were randomly assigned to one of four treatments as follows: (1) commercial standard diet as a control (Con); (2) Con+50 g short-chain oligofructose/kg (OF); (3) C+50 g long-chain inulin/kg (lcIN); or (4) Con+50 g OF -lcIN/kg (Mix OF -lcIN). Changes in bacterial population groups in response to feeding these diets were investigated with 16S rRNA-targeted probes applied in in situ hybridization. Mix OF -lcIN-and lcIN-containing diets resulted in larger numbers of caecal, colonic and faecal bacteria of the Clostridium coccoides -Eubacterium rectale cluster than Con (10 : 6 and 10 : 3 v. 9 : 5 log 10 /g wet wt), whereas OF alone did not affect this bacterial group in caecum, colon or faeces. A bifidogenic effect was only observed in the colon and faeces of OF-treated rats. More lactobacilli were found in caecal and colonic contents of Mix OF -lcIN-fed rats and in faeces of OF-fed rats compared with Con. Mix OF -lcIN and OF led to significantly smaller numbers of caecal, colonic and faecal bacteria belonging to the Clostridium histolyticum and C. lituseburense groups than Con (6 : 8 and 6 : 9 v. 7 : 9 log 10 /g wet wt). Counts of total bacteria, Bacteroides -Prevotella and Enterobacteriaceae did not differ between the groups. OF and/or lcIN-containing diets significantly increased the caecal and colonic concentration of butyrate and its relative molar proportion. Only lcIN-containing diets resulted in a higher faecal concentration of butyrate than Con. Higher molar proportions of faecal butyrate were observed with all diets that had been supplemented with OF and/or lcIN. Stimulation of butyrate production could be of interest for the prevention of ulcerative colitis and colon cancer.Butyrate: Oligofructose: Inulin: Intestinal microflora: Gnotobiotic ratsThe recent commercialization of inulin (IN) and oligofructose (OF) as food ingredients and fat replacers has served to focus much research on the influence of these substrates on the intestinal ecosystem and colonic function (Roberfroid, 2000). IN and OF occur in plants such as chicory, leek, onion, garlic, artichoke and asparagus at high levels (Roberfroid & Delzenne, 1998;Van Loo et al. 1995). IN and OF are not digested by mammalian enzymes in the alimentary tract, thus contributing to the amount of fermentable carbohydrates in caecum and colon (Alles et al. 1996;Roberfroid, 1997). Fermentation of OF and IN in the gut may favour the production of short-chain fatty acids (SCFA) such as acetate, propionate and butyrate and sometimes of lactate (Cummings & Macfarlane, 1997). The ro...

A controlled study with eight healthy free-living subjects was carried out, in which energy intake was adjusted to the individual energy requirements. On administration of inulin, blood lipids, the faecal microflora, short-chain fatty acids and accompanying gastrointestinal symptoms were characterized in order to investigate the long-term effect of inulin. During the run-in phase (8 d), subjects received a typical Western diet providing 45 % energy as fat and 40 % energy as carbohydrate. Subsequently, the subjects consumed a fat-reduced diet which provided 30 % energy as fat and 55 % energy as carbohydrate for a period of 64 d using inulin as a fat replacer. The amounts of inulin consumed by the subjects (up to 34 g/d) were based on individual energy requirements with the aim to keep the diet isoenergetic with that used in the run-in period. To assess the effects of inulin administration, a control study (run-in and intervention) was carried out in which subjects consumed the same diet but devoid of inulin during the whole course of the study. To investigate the effect of inulin on faecal flora composition total bacteria and bifidobacteria in the faeces were enumerated by in situ hybridization with 16S rRNA targeted oligonucleotide probes. Inulin significantly increased bifidobacteria from 9⋅8 to 11⋅0 log 10 /g dry faeces and caused a moderate increase in gastrointestinal symptoms such as flatulence and bloatedness, whereas blood lipids and short-chain fatty acids remained essentially unaffected. Inulin: Blood lipids: BifidobacteriaIn contemporary Western societies the lifestyle is characterized by a high dietary energy input due to a surplus of alimentary fat and reduced physical activity, leading to an increased incidence of adiposity. To meet dietary guidelines aimed at lowering fat consumption to prevent overweight and, at the same time, satisfying the consumer's enjoyment, the food industry has developed low-fat products using fat replacers. Such a fat replacer is inulin from chicory (Cichorium intybus) roots or Jerusalem artichoke (Helianthus tuberosus), which may help to improve the acceptability of low-fat food products by the consumer while also contributing to decreases in energy intake and body weight (Dreon et al. 1988;Grundy, 1991;Bruhn et al.

The establishment of the faecal flora of 39 full-term infants fed exclusively on breast milk (n = 20) or with two different modern adapted cow's milk formulas (n = 19) was studied during the first 3 months of life. One formula investigated was based on 100% bovine casein as the protein source whereas the other formula contained bovine milk proteins with a whey/casein ratio of 60:40. A faecal flora rich in bifidobacteria was found in all study groups; the growth of putrefactive bacteria (especially Bacteroides spp.), however, was limited. In formula-fed infants, significantly higher bacterial counts of enterococci and clostridia were detected compared to breast milk-fed infants. Similarities and differences due to the feeding regimen were particularly reflected in the pattern of the anaerobic bacterial species. Bifidobacterium bifidum, B. infantis and B. breve constituted the majority of the bifidobacterial flora independent of the type of milk feeding. Other bifidobacterial species such as B. longum, B. adolescentis, B. parabifidum and B. pseudo-catenulatum were detected in high numbers and at low frequencies in breastfed infants. The latter three were observed in infants fed the whey/casein formula as well. It seems that infants fed a casein formula develop a faecal flora more like that of breastfed infants concerning Lactobacillus spp. (especially L. fermentum and L. brevis).