Fibre and enteral nutrition

The effects of functional fiber on postprandial glycemia, energy intake, satiety, palatability and gastrointestinal wellbeing: a randomized crossover trial

BACKGROUND

Fiber intakes in developed countries are generally below those recommended by relevant authorities. Given that many people consume fiber-depleted refined-grain products, adding functional fiber will help to increase fiber intakes. The objective of the study was to determine metabolic and sensory effects of adding fiber to bread.

METHODS

A double-blind pair of randomized crossover trials with a two-week washout in which two fiber-containing breads were compared with control bread. The functional fiber (fruit fiber and FibreMax) was added to yield 10 g fiber per serve (two slices). Eighty participants (n = 37 fruit fiber and n = 43 FibreMax) consumed one serve of bread (fiber or control) followed three hours later by a pasta meal consumed ad libitum. Outcome measures included glycemia, satiety, palatability, gastrointestinal wellbeing, visual appeal and subsequent energy intake of the pasta meal. Multivariate regression was undertaken to test for differences between treatment and control for blood glucose, satiety, and cumulative energy intake. Satiety responses were also compared by splitting the data into an immediate response after eating (0-30 min) and a return to hunger analysis (30-180 min). A Wilcoxon sign rank test was used for the first component (0-30 min) and Wilcoxon matched-pairs signed-rank test for the second component (30-180 min). Between treatment differences for gastrointestinal wellbeing were tested using Pearson's chi-square test or Fisher's exact test.

RESULTS

Consumption of the fruit fiber bread reduced postprandial glycemia by 35% (95% CI 13 to 51; P = 0.004) and cumulative energy intake by 368 kJ (95% CI 163 to 531; P = 0.001). There was little influence on satiety and the bread was rated as having poor taste and smell whilst generating feelings of nausea in some participants. FibreMax enriched bread reduced glycemia by 43% (95% CI 17 to 61; P = 0.004) without influence on energy intake or satiety. Apart from a lower visual appeal, the FibreMax bread was palatable. Neither bread caused gastrointestinal discomfort related to flatulence or bloating.

CONCLUSIONS

Enriching bread with 10 g of functional fiber per serve is feasible although reformulation is needed to create not only an acceptable bread, but a desirable product.

Endogenous cellulase enzymes in the stick insect (Phasmatodea) gut

High cellulase (endo-beta-1,4-glucanase) activity was detected in the anterior midgut of the walking stick (Phasmatodea) Eurycantha calcarata. The enzyme was isolated and analyzed via mass spectrometry. RT-PCR revealed two endoglucanase genes, EcEG1 and EcEG2. Mascot analysis of the purified enzyme confirms it to be the product of gene EcEG1. Homologous cDNAs were also isolated from a distantly related species, Entoria okinawaensis, suggesting a general distribution of cellulase genes in phasmids. Phasmid cellulases showed high homology to endogenously-produced glycoside hydrolase family 9 (GH9) endoglucanases from insects, especially to those of termites, cockroaches, and crickets. The purified E. calcarata enzyme showed clear antigency against an anti-serum for termite GH9 cellulase, which, together with the sequence homology, further suggests an endogenous origin of the enzyme. This discovery suggests a possible nutritive value for cellulose in the leaf-feeding phasmids, unlike in herbivorous Lepidoptera.

Dietary roles of non-starch polysaccharides in human nutrition: a review

Nonstarch polysaccharides (NSPs) occur naturally in many foods. The physiochemical and biological properties of these compounds correspond to dietary fiber. Nonstarch polysaccharides show various physiological effects in the small and large intestine and therefore have important health implications for humans. The remarkable properties of dietary NSPs are water dispersibility, viscosity effect, bulk, and fermentibility into short chain fatty acids (SCFAs). These features may lead to diminished risk of serious diet related diseases which are major problems in Western countries and are emerging in developing countries with greater affluence. These conditions include coronary heart disease, colo-rectal cancer, inflammatory bowel disease, breast cancer, tumor formation, mineral related abnormalities, and disordered laxation. Insoluble NSPs (cellulose and hemicellulose) are effective laxatives whereas soluble NSPs (especially mixed-link β-glucans) lower plasma cholesterol levels and help to normalize blood glucose and insulin levels, making these kinds of polysaccharides a part of dietary plans to treat cardiovascular diseases and Type 2 diabetes. Moreover, a major proportion of dietary NSPs escapes the small intestine nearly intact, and is fermented into SCFAs by commensal microflora present in the colon and cecum and promotes normal laxation. Short chain fatty acids have a number of health promoting effects and are particularly effective in promoting large bowel function. Certain NSPs through their fermented products may promote the growth of specific beneficial colonic bacteria which offer a prebiotic effect. Various modes of action of NSPs as therapeutic agent have been proposed in the present review. In addition, NSPs based films and coatings for packaging and wrapping are of commercial interest because they are compatible with several types of food products. However, much of the physiological and nutritional impact of NSPs and the mechanism involved is not fully understood and even the recommendation on the dose of different dietary NSPs intake among different age groups needs to be studied.

The effect of a fibre free and fibre supplemented polymeric enteral diet on normal human bowel function

Although the effects of dietary fibre in a normal diet on intestinal function are well known, the effects of supplementing enteral diet with fibre on intestinal function are not so clear. The aims of the present study were two fold: firstly to compare intestinal function during ingestion of a self selected diet and fibre free polymeric enteral diet and secondly to investigate the effect of adding the fibre source, soy polysaccharide to the same polymeric diet, on bowel function. Six healthy subjects were randomly assigned to 3 treatment periods (7 days) of a self selected diet (SSD), 2 l polymeric enteral diet (ED), or 2 l of the same polymeric enteral diet supplemented with 20 g/l of soy polysaccharide fibre (SPED). Parameters measured were bowel frequency/day, mean daily wet stool weights and whole gut transit time. Highest stool wet weights (g/24 h +/- SEM) were obtained from subjects consuming a SSD (180.3 +/- 30.6). This was significantly higher (p < 0.02) than those consuming an ED (81.9 +/- 14.5) but not a SPED (123 +/- 22.3). Whole gut transit (h +/- SEM) on a SSD (47 +/- 5.9) was significantly (p < 0.05) quicker than on an ED (73 +/- 4.9), but not significantly different from those ingesting a SPED (54 +/- 5.5). Bowel frequency/day (+/- SEM) in subjects consuming a SPED (1.0 +/- 0.1) was significantly (p < 0.02) higher than in subjects ingesting an ED (0.8 +/- 0.1) but was not significantly different when compared to a SSD (1.0 +/- 0.2). We conclude that ingestion of an ED results in significantly longer whole gut transit time, significantly decreased daily stool wet weights and decreased bowel frequency when compared to a SSD. The ingestion of 30 g of soy polysaccharide in a polymeric enteral diet not only tends to normalise whole gut transit time and daily stool wet weights, but also significantly increases bowel frequency when compared with values seen during the consumption of a fibre free polymeric enteral diet.

The influence of soyfibre supplemented tube feeding on the occurrence of diarrhoea in postoperative patients

We investigated the occurrence of diarrhoea in postoperative patients on tube feeding, with or without soyfibre supplementation. The patients also received antibiotic treatment. 60 postoperative patients were assigned to either a fibre free formula diet (FFF) or a soyfibre supplemented formula diet (SSF). The tube feeding was supplied continuously through a nasogastric or a jejunal tube (mean volume 1775 ml a day). The consistency and frequency of the bowel evacuations were recorded for a period of 5 days. A daily diarrhoea score (DS) was obtained by adding a consistency score (formed stools 1, loose 3, and watery 5 points) for every evacuation. The major finding of this study is that the total DS of the FFF group was 1.7 times higher than the SSF group (ANOVA, p = 0.05). We conclude that soyfibre enriched tube feeding has a beneficial and significant influence on the occurrence of diarrhoea in a selected group of postoperative patients.

Systematic review and meta-analysis: the clinical and physiological effects of fibre-containing enteral formulae

BACKGROUND

Enteral nutrition can be associated with gastrointestinal side effects and fibre supplementation has been proposed as a means to normalize bowel function.

AIM

To evaluate systematically the effects of fibre supplementation of enteral feeds in healthy volunteers and patients both in the hospital and community settings.

METHODS

Electronic and manual bibliographic searches were conducted. Controlled studies in adults or children, comparing fibre-supplemented vs. fibre-free formulae given as the sole source of nutrition for at least 3 days, were included.

RESULTS

Fifty-one studies (including 43 randomized-controlled trials), enrolling 1762 subjects (1591 patients and 171 healthy volunteers) met the inclusion criteria. Fibre supplementation was generally well tolerated. In the hospital setting, the incidence of diarrhoea was reduced as a result of fibre administration (OR 0.68, 95% CI: 0.48-0.96; 13 randomized-controlled trials). Meta-regression showed a more pronounced effect when the baseline incidence of diarrhoea was high. In both patients and healthy subjects, fibre significantly reduced bowel frequency when baseline frequency was high and increased it when it was low, revealing a significant moderating effect of fibre.

CONCLUSIONS

The review indicates that the fibre-supplemented enteral formulae have important physiological effects and clinical benefits. There is a need to use a consistent approach to undertake more studies on this issue in the community setting.

Colostrum protein concentrate enhances intestinal adaptation after massive small bowel resection in juvenile pigs

OBJECTIVES

Short bowel syndrome (SBS) usually results from the surgical removal of a large segment of small intestine. Patient outcome depends on the extent of intestinal resection and adaptation of the remaining intestine. We evaluated the impact of colostrum protein concentrate (CPC) on intestinal adaptation after massive small bowel resection in a porcine model of infant SBS.

METHODS

Four-week-old piglets underwent an approximate 75% small bowel resection (R, n = 23) or a control transection operation (C, n = 14). Postoperatively, animals from both groups received either pig chow (R = 6, C = 5), polymeric infant formula (R = 6, C = 3) or polymeric infant formula supplemented with CPC (R = 11, C = 6) for 8 weeks until sacrifice. Clinical outcome measures included weight gain and stool consistency. Morphologic measures were intestinal villus height and crypt depth. Functional outcome measure was mucosal disaccharidase activity.

RESULTS

Resected animals fed polymeric infant formula alone had reduced weight gain compared with controls fed the same diet (P < 0.005). Despite massive small bowel resection, animals fed pig chow or polymeric infant formula supplemented with CPC grew at an equivalent rate to controls fed polymeric infant formula alone. Resected animals supplemented with CPC had increased villus length and crypt depth in the jejunum (P < 0.001) and ileum (P < 0.001) compared with resected animals fed either pig chow or polymeric infant formula alone.

CONCLUSION

In an animal model of SBS, CPC supplementation of polymeric infant formula resulted in normal weight gain and features of enhanced morphologic adaptation.

The effect of a polymeric enteral formula supplemented with a mixture of six fibres on normal human bowel function and colonic motility

BACKGROUND AND AIMS

Fibres with varying fermentability may improve bowel function during enteral feeding. Two studies in healthy volunteers aimed to 1) investigate effects of Nutrison Multi Fibre (NMF) on gastrointestinal function, and 2) compare effects of NMF administered orally and nasogastrically on distal colonic motor activity.

METHODS

(1) Ten subjects were randomly assigned to 3x7 days self-selected diet (SSD), 2 litres Nutrison Standard (NS), or 2 l NMF. Objective and subjective indices were measured. (2) Two groups (n=6) received 2x250 ml boluses of NMF 2 hourly either nasogastrically or orally. Distal colonic motility was measured for 8 h (3 pre/5 post) first bolus.

RESULTS

Whole gut transit time was prolonged during NS (P<0.05) compared with SSD or NMF. Stool wet weight was higher during SSD (P<0.05) than during NS or NMF. Bowel frequencies were comparable. NMF was well tolerated. 2. Colonic activity index was maintained after oral administration with no associated diarrhoea. Activity index decreased after nasogastric bolus (P<0.05), but recovered to higher than fasting levels (P<0.05). 5 subjects had watery stools.

CONCLUSIONS

Oral NMF is well tolerated, normalises whole gut transit time and maintains colonic motility. Recovery of colonic activity after nasogastric bolus suggests a putative protective effect of NMF over a longer period of feeding.

Formulation of enteral diets

The number of enteral diets has increased from a handful in the 1970s to over 100 at present. These can be classified as polymeric, chemically defined, disease-specific, and specialized diets, as well as oral dietary supplements. The properties, indications, pros and cons for the use of these diets are outlined in an effort to assist clinicians in their selection.

Constipation in epidermolysis bullosa: successful treatment with a liquid fiber-containing formula

In epidermolysis bullosa (EB), chronic constipation, painful defecation, and fecal impaction frequently contribute to malnutrition and growth failure. Standard treatments for constipation, such as increased intake of conventional dietary fiber and fluids and/or the use of laxatives and stool softeners, are largely unsuccessful. We evaluated by questionnaire the use of a fiber-containing liquid formula (Enrich) in 20 chronically constipated children with dystrophic EB. All derived substantial improvement in constipation when taking 250 to 750 ml Enrich per day. We recommend that such a fiber-containing food be prescribed for chronic constipation in EB. In cases of fecal impaction, this should be preceded by bowel cleansing.

Nutritional management of patients with gastrointestinal fistulas

Nutritional support plays a key and integral role in the management of patients with gastrointestinal fistulas. It needs to be instituted early to minimize erosion of body cell mass, to prevent further physiologic deterioration of the patient, and to initiate repletion in an otherwise malnourished patient. Furthermore, it allows for rest of the gastrointestinal tract and facilitates healing of the fistula.

The effect of dietary fiber in tube-fed elderly patients

Diarrhea is a common problem with potentially serious consequences for elderly tube-fed patients. A review of the literature indicates that diarrhea has been associated with the use of antibiotics, low blood albumin concentration, and a lack of fiber in the diet. This study documents the observed effect of dietary fiber on the incidence of diarrhea in 50 tube-fed patients. Over a 3-week period, patients who received fiber-containing formula had fewer liquid/loose stools than patients who received fiber-free formula. Nurses who care for elderly, tube-fed patients can help to improve outcomes by advocacy and interdisciplinary collaboration with registered dietitians and primary providers and by teaching assistive staff the importance of accurate recording of bowel function.

Enhanced apoptosis in transformed human lung fibroblasts after exposure to sodium butyrate

Simian virus-transformed human cells, WI-38 VA13A, showed a dose-dependent induction of apoptosis and reduction in cell numbers after exposure to sodium butyrate. Apoptosis was confirmed by ApopTag staining, isolation of apoptotic envelopes, and immunofluorescent staining with an antibody specific for apoptotic envelopes. Examination of the cell cultures by phase contrast and fluorescent microscopy revealed the presence of enlarged cells that displayed a more flattened morphology and morphological changes in the nucleus of cells exposed to sodium butyrate. Cell proliferation assays showed control and sodium butyrate cultures were synthesizing DNA and excluded any cytotoxic effects of sodium butyrate. Flow cytometry results indicated an increase in the number of aneuploid cells following sodium butyrate treatment. There was a decrease in the percentage of cells in G2/M in the diploid populations, but an increase in the percentage of cells in G2/ M in aneuploid populations. This human in vitro model system suggests a mode of action for the therapeutic effects of sodium butyrate, which have been observed in the topical treatment of neoplastic cells and reversal of symptom in ulcerative colitis, namely, the induction of apoptosis.

Pectin-supplemented enteral diet reduces the severity of methotrexate induced enterocolitis in rats

BACKGROUND

Administration of methotrexate (MTX) to rats fed an elemental diet results in a high mortality from severe enterocolitis. Previous studies have shown that pectin is an important precursor of substrates for intestinal structure and function and may facilitate intestinal recovery after enterocolitis. The aim of this study is to evaluate the effect of pectin on MTX-induced enterocolitis in rats.

METHODS

Rats received intragastric infusion of either 1% pectin-supplemented or pectin-free elemental diet from the beginning of the study via a gastrostomy. On the 4th day animals received either MTX, 20 mg/kg intraperitoneally, or saline injection and were killed on the 7th day for sampling.

RESULTS

Pectin supplementation significantly decreased body weight loss, organ water content, and intestinal myeloperoxidase levels and increased mucosal protein, DNA, and RNA content in enterocolitis rats. The intestinal permeability was increased by administration of MTX, and pectin supplementation significantly reversed the increased permeability in the distal small bowel and colon. Pectin supplementation also lowered the magnitude of bacterial translocation, decreased plasma endotoxin levels, and restored bowel microecology.

CONCLUSIONS

Pectin significantly decreased MTX-induced intestinal injury and improved bowel integrity.

Influence of three different fiber-supplemented enteral diets on bowel function and short-chain fatty acid production

BACKGROUND

Dietary fiber is known to influence bowel habit and gastrointestinal mucosal cell morphology and function. large-bowel function is particularly influenced by insoluble, poorly fermentable fiber sources, whereas mucosal function is affected by fiber sources that are soluble and highly fermentable. The aim of the present study was to compare bowel function during consumption of a self-selected diet, a fiber-free enteral diet, and three polymeric enteral diets, each supplemented with a fiber with different fermentation characteristics. The fiber sources used were oat, soy oligosaccharide, and soy polysaccharide.

METHODS

Seven healthy subjects consumed four diets in random order for 4 to 7 days. These were a self-selected diet, a 2-L polymeric enteral diet, and a 2-L polymeric enteral diet supplemented with 15 g of total dietary fiber per liter derived from either soy oligosaccharide fiber (75 g/L) or oat fiber (15 g/L). An additional six healthy subjects were randomly assigned to three diets (4 to 7 days): a self-selected diet, a 2-L polymeric enteral diet, or the same 2-L polymeric enteral diet supplemented with 20 g of soy polysaccharide fiber per liter (15 g of total dietary fiber per liter). Bowel function was assessed by measuring whole-gut transit time, mean daily stool wet weights, and bowel movement frequency per day. Fermentation characteristics of the different fiber sources were determined quantitatively and qualitatively by measuring short-chain fatty acids produced during in vitro stool culture.

RESULTS

Total short-chain fatty acid and butyric acid production with soy oligosaccharide fiber were significantly higher compared with values observed for soy polysaccharide fiber (p < .003), oat fiber (p < .005), and self-selected (control) diet (p < .003). Compared with the fiber-free diet, consumption of the soy polysaccharide, oat, and soy oligosaccharide-fiber-supplemented enteral diets did not significantly (p > .05) alter whole-gut transit time or stool wet weight. However, bowel frequency was significantly improved by consumption of the soy polysaccharide-fiber-supplemented diet but not the oat fiber or soy oligosaccharide-fiber-supplemented diets.

CONCLUSION

Compared with a fiber-free polymeric enteral diet, the daily consumption of an enteral diet supplemented with 30 g of total dietary fiber per day derived from a poorly fermentable oat fiber, a highly fermentable soy oligosaccharide fiber, or a moderately fermentable soy polysaccharide fiber has little impact, if any, on bowel function.

Water-soluble ethylhydroxyethyl cellulose: a new agent against bacterial translocation from the gut after major liver resection

BACKGROUND

Bacterial translocation from the gut to extraintestinal sites has been demonstrated as a mechanism explaining bacterial infectious complications after various insults.

METHODS

To explore the potential therapeutic value of water-soluble ethylhydroxyethyl cellulose (EHEC). Its effects on macrophage phagocytic capacity, bacterial adherence on the intestinal surface, and bacterial growth were evaluated both in vivo and in vitro.

RESULTS

Preoperative administration of EHEC reduced the incidence of bacterial translocation from the gut to mesenteric lymph nodes and blood and prevented overgrowth by enteric bacteria after 70% or 90% hepatectomy. Uptake of macrophages harvested from blood decreased after intravenous administration of EHEC. EHEC diminished the otherwise increased bacterial adherence on the intestinal surface induced by major liver resection. EHEC in bacterial cultures for over 1 h was capable of inhibiting bacterial growth and delaying bacterial DNA synthesis in vitro.

CONCLUSIONS

The present study indicates that EHEC could be a potential agent for the prevention of gut-origin sepsis.

Rationale and efficacy of specialized enteral nutrition

Enteral nutrition, whenever feasible, is the preferred route of nutrition support. There has been a tremendous increase in the number of enteral products available on the market. Many of these are designed for use in specific disease states. This review will summarize the scientific rationale and supporting research for specialized enteral nutrition.

Butyrate oxidation is impaired in the colonic mucosa of sufferers of quiescent ulcerative colitis

The short chain fatty acids, acetate, propionate, and butyrate are produced by colonic bacterial fermentation of non-starch polysaccharides. Butyrate is the major fuel source for the colonic epithelium and there is evidence to suggest that its oxidation is impaired in ulcerative colitis. Triplicate biopsy specimens were taken at colonoscopy from five regions of the large bowel in 15 sufferers of ulcerative colitis. These patients all had mild or quiescent colitis as assessed by clinical condition, mucosal endoscopic and histological appearance. The rate of oxidation of glucose, glutamine, and butyrate through to carbon dioxide was compared with that in biopsy specimens from 28 patients who had no mucosal abnormality. Butyrate (272 (199-368)) was the preferred fuel source for the colitic mucosa followed by glutamine (33 (24-62)) then glucose (7.2 (5.3-15)) pmol/micrograms/hour; medians and 95% confidence intervals, p < 0.01. There was no regional difference in the rate of utilisation of these metabolites. In the group with colitis the rate of butyrate oxidation to carbon dioxide was significantly impaired compared with that in normal mucosa decreasing from 472 (351-637) pmol/micrograms/hour to 272 (199-368) pmol/micrograms/hour; median and 95% confidence intervals, p = 0.016. The rate of glucose and glutamine utilisation were not significantly different between normal and colitic mucosa. These data confirm that in quiescent ulcerative colitis there is an impairment of butyrate oxidation.

Causes of diarrhea in tube-fed patients: a comprehensive approach to diagnosis and management

In the absence of a standard definition for diarrhea, clinicians have developed their own descriptions, such as an increased frequency of stools, an increased quantity of water in the stool, an increased weight of the stool, or a change in the consistency of the stool. The clinician should first determine whether the diarrhea is osmotic or secretory. Diarrhea in patients who receive enteral nutrition is often caused by such conditions as diabetes, malabsorption syndromes, infection, gastrointestinal complications, or concomitant drug therapy instead of the enteral formula. Factors related to the enteral nutrition that may contribute to diarrhea include the composition of the formula, the manner of administration, or bacterial contamination. To ensure that the nutritional requirements of patients are met and the appropriate treatment is administered, all of the possible causes of diarrhea should be considered before discontinuing or reducing the amount of formula delivered.

Therapeutic role of dietary fibre

The current status of dietary fibre and fibre supplements in health and disease is reported, and the components of dietary fibre and its respective mechanical and metabolic effects with emphasis on its therapeutic potential are reviewed. Practical management guidelines are provided to help physicians encourage patients identified as having fibre deficiency to increase dietary fibre intake to the recommended level.

Water-soluble ethylhydroxyethyl cellulose prevents bacterial translocation induced by major liver resection in the rat

Enteric bacteria might act as pathogens, translocating across the intestinal barrier to extraintestinal sites after major liver resection. In the current study, water-soluble ethylhydroxyethyl cellulose (EHEC) was administered before hepatectomy to evaluate the influence on bacterial translocation induced by major liver resection, phagocytic capacity by visceral and circulating macrophages, enteric bacterial population, and bacterial adherence on the intestinal surface in rats subjected to sham operation or to 70% or 90% hepatectomy. Oral or intravenous (IV) administration of EHEC reduced the incidence of bacterial translocation to mesenteric lymph nodes (MLN) and blood after major liver resection. Oral EHEC appeared more effective than IV administration in protecting against bacterial translocation to MLN in animals with 90% hepatectomy. Ethylhydroxyethyl cellulose (oral and IV) significantly diminished intestinal macrophage uptake capacity of 125I-labeled, heat-killed Escherichia coli as compared with animals without EHEC administration. Overgrowth or colonization of enteric bacteria after major liver resection could be prevented by oral or IV EHEC. Adherence of 14C-labeled, alive E. coli on the intestinal mucosa decreased after EHEC treatment in animals subjected to major liver resection. Systemic arterial pressure and intestinal blood flow markedly decreased from 1 hour and on after 90% hepatectomy. Intravenous administration of EHEC did not improve these alterations. Bacterial hydrophobicity and surface negative charge were significantly reduced 1 hour after bacterial culture with EHEC. Thus, EHEC appears to be a potent agent preventing translocation of enteric bacteria from the gut after major liver resection, by altering the surface characters of enteric bacteria, balancing the enteric microflora, inhibiting bacterial attachment onto the intestinal surface, and blocking phagocytosis by intestinal macrophages.

Results of pouch surgery after ileo-anal anastomosis: the implications of pouchitis

The ileal pouch-anal operation is the procedure of choice for those suitable patients requiring surgery for chronic ulcerative colitis or familial adenomatous polyposis. The functional results are generally good but pouchitis remains a significant and poorly understood complication. This review encompasses factors relating to pouchitis, e.g., bacteriological, functional and histological changes, with emphasis on its biology and treatment, and the long-term implications.

Medical management of severe inflammatory disease of the rectum: nutritional aspects

It is clear that the nutritional state of patients with inflammatory bowel disease is often impaired and can be improved by the provision of nutritional support. Improvement in nutritional status can be achieved as effectively with enteral as with parenteral nutrition. Nutritional support appears to have no primary therapeutic effect in patients with ulcerative colitis. With regard to nutritional support in Crohn's disease, parenteral nutrition should be restricted to use as supportive rather than primary therapy. Available information now seems to suggest that most of the benefits of parenteral nutrition in Crohn's disease are related to an improvement in nutritional state rather than as primary therapy, and its use should be restricted to the treatment of specific complications of Crohn's disease, such as intestinal obstruction related to stricture formation or short bowel syndrome following repeated resection. Although some doubt exists over the efficacy of oligopeptide-containing elemental and polymeric enteral diets, the present evidence indicates that chemically defined free amino acid-containing elemental diets have primary therapeutic efficacy in the management of acute exacerbations of Crohn's disease. As such, these diets are worthy of therapeutic trial in patients with severe Crohn's disease involving the distal colon and rectum, particularly in those patients who are malnourished and who prove to be resistant to treatment with a combination of topical corticosteroids and 5-aminosalicylic acid-containing compounds. Clinicians should be aware, though, that the beneficial effects are likely to be restricted to the short term, with high relapse rates by 1 year, this being particularly so in patients with distal Crohn's proctocolitis (Teahon et al, 1988). Volatile fatty acid enemas clearly have potential in the management of patients with severe steroid-resistant proctitis. Finally, one of the most important observations made in recent years is the one concerning the large losses of nitrogen that will occur in patients with inflammatory bowel disease treated with corticosteroids in the absence of adequate protein intake (O'Keefe et al, 1989). Hopefully the days of treating patients with severe inflammatory bowel disease with high dose corticosteroids and a peripheral dextrose or dextrose-saline drip have passed into history.

Evaluation of the effect of a fiber-enriched formula on infant colic

Because infants with colic appear to have abdominal pain similar to that of adults with irritable bowel syndrome, who may benefit from the addition of fiber to their diet, we tested whether fiber added to infant formula would alleviate colic. Twenty-seven normal, term infants (aged 2 to 8 weeks; 14 girls) with colic, defined as crying plus fussing for more than 3 hours a day for at least 3 days of a 6-day baseline period, were enrolled. Infants were randomly assigned in 9-day periods to a sequence of placebo (Isomil formula) followed by fiber-supplemented formula (Isomil plus soy polysaccharide) (n = 12) or the reverse (n = 15). Daily diaries of crying, fussing, sleeping, formula, intake, and stooling were kept. Twenty-two infants completed three lactulose breath hydrogen tests at the end of the baseline period and after each study period. The crossover trial was followed by 30 to 35 days of use of the study formula chosen by the parents as most beneficial but unknown to the investigators. Growth was monitored throughout. Serum cholesterol, calcium, phosphate, albumin, iron, and zinc concentrations were measured at the conclusion. There were no significant differences in average daily time spent by the infants in fussing and crying during ingestion of the fiber-supplemented formula. However, parents of 18 of 27 infants chose fiber-supplemented formula as most beneficial in ameliorating symptoms of colic. While the infants were consuming fiber-supplemented formula, stool frequency increased, and breath hydrogen excretion increased significantly, in response to lactulose. Growth and serum biochemical measurements were normal in all infants. Supplementation of infant formula with the level of soy polysaccharide used in this study may have reduced crying and fussing in some infants but did not affect colicky behavior in the majority of infants, who continued to cry and fuss excessively.

Determination of the fiber content of enteral feedings

The importance of dietary fiber in maintaining optimum bowel function has been shown in feeding studies, and many enteral formulas now contain dietary fiber, usually as soy polysaccharide (SP). Generally only total dietary fiber (TDF) values are given on the label or in product literature, with no indication of insoluble dietary fiber (IDF) and soluble dietary fiber (SDF) content. Often product literature highlights the amount of SP contained in the formula, not the TDF. The method used to determine TDF content usually is not specified, making it impossible to compare products on a TDF basis. We compared the dietary fiber content of commercially available enteral formulas objectively to help clinicians make informed choices when selecting fiber-containing formulas. Fiber-containing formulas by suppliers were freeze-dried and total, water-soluble, and water-insoluble dietary fiber measured by the Association of Official Analytical Chemists (AOAC) approved method. TDF per 1000 mL ranged from 4.0 to 9.9 g for blenderized formulas and from 7.2 to 20.3 g in formulas containing SP. IDF values per 1000 mL ranged from 2.0 to 5.4 g for blenderized product, and the soy formulas ranged from 5.5 to 16.9 g. SDF values per 1000 mL ranged from 2.0 to 4.5 g in blenderized products, and in soy formulas SDF ranged from 1.7 to 3.8 g. Differences in physiological effects of fiber-containing enteral formulas may be because of differences in fiber composition.

Diarrhoea during enteral feeding in the critically ill: a comparison of feeds with and without fibre

This randomised double-blind study examined the frequency of diarrhoea in intensive care unit patients given a fibre-containing feed, Enrich, and a fibre-free feed, Ensure. A daily 'diarrhoea score' was calculated from the frequency, volume and consistency of the stools. A score greater than 12 indicated diarrhoea, and greater than 50 severe diarrhoea. Ninety one patients met the criteria for participation: Enrich 45, Ensure 46. The groups were similar in age, sex ratio, feed volume, antibiotic usage, upper gastro-intestinal bleeding prophylaxis and plasma albumin concentrations. Diarrhoea occurred in 16 patients given Enrich and 13 given Ensure, severe diarrhoea affecting 5 and 9 respectively (NS). Forty seven of 343 (14%) Enrich feeding days and 51 of 342 (15%) Ensure feeding days were complicated by diarrhoea--severe diarrhoea: 8 and 12 feeding days (NS). We conclude soy polysaccharide (21 g/L) did not reduce diarrhoea in intensive care unit patients given enteral feeds.