Efficacy of Benefiber-Added, Reduced-Osmolarity WHO-ORS in the Treatment of Cholera in Adults
Efficacy of Benefiber-Added, Reduced-Osmolarity WHO-ORS in the Treatment of Cholera in Adults
In cholera, the function of small intestine is affected resulting in increased secretion of
 electrolytes and water and their reduced absorption leading to profuse watery diarrhoea. The
 human colon has the capacity to absorb water and electrolytes. A number of recent studies
 have shown that short chain fatty acids (SCFAs) such as acetate, butyrate and propionate
 stimulates absorption of sodium in the colon, which is not affected by cyclic AMP. It has
 also been shown that SCFAs inhibits c-AMP mediated chloride secretion in the colon. Benefiber
 (partially hydrolyzed guar gum) is water soluble fibre, and when added to ORS it undergoes
 fermentation in the colon liberating SCFAs. SCFAs not only serves as metabolic fuel to the
 enterocytes but they also enhance colonic absorption of salts and water. Thus, they have
 potentials to reduce the severity of diarrhoea in patients with cholera. The aim of this
 study is to assess the efficacy of Benefiber-added WHO-ORS in the management of adults with
 cholera. In this randomized, controlled clinical trial, a total of 174 adult males with
 cholera would be studied. Study patients would be selected from those who attend the Dhaka
 Hospital of ICDDR,B with a history of diarrhoea of less than 24 hours and signs of severe
 dehydration. They would be rehydrated using intravenous fluid (cholera saline) over 4 hrs
 during which a stool specimen would be subjected for dark-field microscopy for identification
 of V. cholerae. Those identified to have cholera would be randomized in equal numbers to
 receive either: a) Benefiber (25 g/L) added WHO-ORS, b) Benefiber (50 g/L) added to the new
 formulation (Na+ 75, glucose 75, Cl- 65, K+ 20 mmol/L, citrate 10 mmol/L, osmolarity 245
 mosmol/L) of WHO-ORS , or c) the same WHO-ORS but without Benefiber for maintenance of
 hydration until resolution of diarrhoea. All patients would be treated with a single, 300 mg
 dose of doxycycline capsules and would be provided with the standard hospital diets. Fluid
 intake (intravenous fluid, ORS, and plain water) and output (stool, urine, and vomit) will be
 measured for each 6-hourly periods of the study. Patients would be hospitalized until
 resolution of their diarrhoea. Stool output, intake of intravenous fluid and ORS, the
 duration of diarrhoea, and the proportion of patients requiring "unscheduled intravenous
 fluid therapy" would be compared between the treatment groups. If Benefiber is found
 effective, it would be possible to formulate improved ORS for better case management of
 cholera.
Considerable interest has recently been generated on dietary fibers (DF), and soluble fibers
 have emerged both as a subject for research and therapeutic applications. The 'fiber
 hypothesis', put forward by Denis Bukitt and Hugh Trowel (1-4), suggests that consumption of
 unrefined carbohydrate food protects against many western ailments including colon cancer,
 diverticular disease, appendicitis, constipation, haemorrhoids, diabetes, heart disease, gall
 stones, and obesity among others. In the line of this hypothesis, many basic laboratory and
 clinical works have been done. The term 'dietary fiber' has been used to denote plant
 polysaccharides and lignin that are resistant to hydrolysis by human digestive enzymes (5,6).
 The detailed chemistry and metabolism of DF have also been studied (7-10). The classification
 of fiber is based on their chemical structures (11), and they can be divided into
 non-polysaccharides and non-starch polysaccharides. Lignin is the only non-polysaccharide
 fiber, which is a polymer of phenolic alcohol that is water insoluble. The non-starch
 polysaccharide can be divided into cellulose and non-cellulose fiber. Cellulose consists of
 un-branched D-glucose chains in 1,4-ß linkage and is water insoluble. Non-cellulose
 polysaccharides include hemicelluloses, mucillages, gums and pectins, and they consists of
 various ß linkages of wide variety of hexose and pentose sugars. The polysaccharide chains
 are heteroglycans (chains with more than one type of monosaccharide). The hemicellulosic
 materials are polymers of xylose, mannose and glucose with side chains of galactose and
 arabinose. The pectic substances are polymers of galacturonic acids. Likewise, the gums and
 mucillages are branched carbohydrate polymers (e.g. gum, which is a linear mannan with
 galactose side chains). Non-cellulose polysaccharides vary in degree of their water
 solubilities (7,9,10).

 In man, fiber is mainly degraded in the large intestine by the bacterial flora. Many of the
 effects of fiber on stool output arise from this degradation. The main products of fiber
 fermentation are short chain fatty acids (SCFAs) including acetate, propionate and butyrate,
 which are the major anions in the colon. Bacteria utilize SCFAs and proliferate, absorbing
 water from the colonic epithelium in the course of their metabolism, and thus decrease the
 free water content in the lumen (11). The SCFAs that are not utilized by the bacteria are
 largely absorbed by the colon (12). Their transepithelial transport is associated with
 stimulation of sodium transport from the colon in several species including human (13-15).
 This effect may be particularly important in acute diarrhoeal diseases where purging, and
 associated reduced food intake might deplete the colon of SCFAs leading to colonic
 dysfunction (16, 17). Thus, luminal SCFAs levels in the colon might influence the clinical
 course of acute diarrhoeal diseases. SCFAs have also been shown to be clinically important in
 one diarrhoeal disease in animal -transmissible gastroenteritis of swine (18). Animals
 infected with the virus develop acute enteritis with marked fluid loss from the small
 intestine. Young animals develop severe diarrhoea as their colonic mucosa is incapable of
 absorbing fluid, whereas older infected animals has been shown to have increased colonic
 absorption by about six-folds over the controls. This compensatory response prevents severe
 diarrhoea and is related to the development of colonic fermentation with the production of
 SCFAs.

 Cholera is a disease of humans affecting the small intestine where fluid and electrolyte
 secretion is increased while their absorptions are decreased leading to profuse watery
 diarrhoea. As the human colon has the capacity to absorb water and electrolyte (19), some
 compensation is expected reducing the diarrhoeal loss. In recent studies (20, 21) SCFAs have
 been shown to stimulate sodium absorption in the colon, an effect that is not influenced by
 c-AMP, and additionally they have been found to inhibit cyclic AMP-mediated chloride
 secretion in the colon.

 The SCFA-enhanced colonic absorption of water and electrolytes might be exploited in the
 treatment of acute diarrhoeal diseases. Oral rehydration therapy has dramatically changed the
 management of acute diarrhoeal disease. Yet, oral rehydration therapy is in the process of
 being improved. Cereal-based oral rehydration solutions (ORS) have been shown to reduce the
 stool volume by about 30% to 40% compared to the WHO-ORS (22, 23). It is possible that, at
 least a part of their effect on stool volume reduction might be attributed to SCFAs produced
 by unabsorbed carbohydrate including dietary fiber in the colon. Diversion colitis is an
 inflammatory process affecting the bypassed colon and rectum following surgical diversion of
 faecal stream (24). The inflammation disappears after surgical re-anastomosis, where topical
 steroids are usually ineffective (25). Rectal instillation of SCFAs has resulted in the
 disappearance of symptoms and endoscopic change over a period of 4-6 weeks; remission has
 been maintained for over a year by regular rectal SCFAs treatment (26). These findings
 suggest that SCFAs also play a role in mucosal healing in colitis

 The colonic epithelial cells utilize SCFAs as source of energy for their various metabolic
 activities (27, 28). Human colonocytes use butyrate in preference to glucose, glutamine or
 ketone bodies as fuel source (27). Thus, in contrast to small intestinal cells, colonic
 epithelial cells derive the major part of their energy supply from the lumen rather than from
 the blood. Depriving luminal nutrition of the mucosa has been found to induce fluid secretion
 (29). The lack of luminal SCFAs in the colon may be involved in special diarrhoeal states
 such as diversion colitis and antibiotic associated diarrhoea. Diarrhoea is not uncommon
 after abdominal operations, particularly after closure of a temporary colostomy (30).
 Although there is no proof, this postoperative diarrhoea might be attributed to lack SCFAs in
 the colon, which might perhaps be reversed by the intake of fermentable fiber (31). Lengthy
 preoperative bowel preparation by antibiotic and lavage, and diminished oral nutrition
 probably contributes to postoperative diarrhoea. Lack of luminal SCFAs can similarly explain
 the diarrhoea often seen in the terminal stages of malnutrition and starvation. In these
 conditions, intestinal infections might not always be implicated and it seems likely that
 diarrhoea is a manifestation of organ-specific malnutrition of the colon (32). Diarrhoea is
 often associated with the use of broad-spectrum antibiotics, and colonization by toxin
 producing clostridium difficile accounts for only a third of these cases (33). The use of
 antibiotics suppresses the formation of SCFAs from fermentable carbohydrate (34), a feature
 that might also be responsible for diarrhoea. Although there are lots of data suggesting
 antidiarrhoeal effect of fermentable fibers, their therapeutic application in diarrhoeal
 disease is yet to be examined. Some recent clinical studies have demonstrated the beneficial
 effect of dietary fiber in treatment of adult cholera (35) and in the treatment of children
 with acute diarrhoea (36). In children with acute diarrhoea, Benefiber-added ORS has been
 observed to reduce the mean duration of diarrhoea by 16 hours, (74 vs. 90 h; p <0.05).
 Further studies are required to evaluate the effect of Benefiber in reducing severity and
 duration of cholera, a form of severe dehydrating diarrhoea.

 Guar gum: a soluble fiber

 Guar gum is a dietary fiber obtained from the endosperm of the seeds of the Indian cluster
 bean (Cyanopsis tetragonolobus) of the family Leguminosae. The guar plant is a pod bearing,
 nitrogen-fixing legume, which has been grown for centuries in India and Pakistan, where it is
 one of the principal crops and is used as food for both humans and animals. It is now being
 grown in America for use in various industries (food, cosmetic and paper industries) (37).

 Chemically, guar gum is a non-starch polysaccharide, a galactomannan, which on contact with
 water form a highly viscous gel. In the colon, guar gum is fermented to form SCFAs.
 Initially, guar gum was used as thickener and emulsion stabilizer in food processing on the
 basis of its gelling property (37). Our present interest about guar gum is its therapeutic
 use as a dietary fiber.

 "Benefiber" (partially hydrolyzed guar gum)

 Guar gum forms gel with water, is rather viscous, and thus unsuitable for therapeutic uses
 (e.g. in liquid enteral nutrition). Benefiber is a partially-hydrolized (in vitro by the
 enzyme endo-B-mannase) guar gum, which is a soluble fiber. It is expected that Benefiber will
 be readily utilized by colonic microflora with the production of the same products of
 fermentation as the guar gum. The partial hydrolysis of the guar gum (e.g. Benefiber) results
 in significant reduction in the viscosity of the solution. It is also expected that it will
 not cause any delay in gastric emptying and also will not interfere with normal absorption of
 macronutrients (carbohydrate, protein and fat). In one study (38), the addition of Benefiber
 to a liquid formulation of diet significantly delayed the colonic transit time without
 affecting the oro-caecal transit time. The result of another recent study (39) in Liestal,
 Switzerland observed that the Benefiber did not affect the absorption of glucose, amino acid
 and fat.

 Benefiber was chosen for this study for several reasons. First, it is partially-hydrolyzed
 guar gum (PHGG), and it completely dissolves in water making a clear solution. Second, other
 fibers are usually viscous, and thus not suitable for use in ORS; the amylase-resistant
 starch is not soluble and it only makes a suspension. Third, in in vitro studies of
 fermentation, using fresh faecal inoculate, SCFAs production was observed to be highest with
 PHGG in comparison with the other commercial fiber substitutes (40). Fourth, in our study in
 non-cholera diarrhoea in children, we observed PHGG to be clinically useful (36). In this
 study (36), we used PHGG in a dose of 20g/L. This dose was selected arbitrarily on the basis
 of standard dose used in the preparation of liquid formulation diets. In the proposed study,
 we would like to test two different doses (25 g/L and 50 g/L) to determine if there is an
 additional benefit of increasing the dose.

 Based on the findings of our previous study as well as studies done elsewhere, we are very
 hopeful that the addition of Benefiber to WHO-ORS would lead to its fermentation in the colon
 resulting in the production of SCFAs, which would improve colonic function including colonic
 absorption of salt and water and thus reduce the stool output as well as shorten the duration
 of diarrhoea in adults with cholera.

 Safety issue of Benefiber

 Benefiber is a food material obtained from vegetable source has been used in cereals, juices,
 shakes, yogurt, soups, backed goods, and as a fiber source in enteral nutrition products. It
 has undergone extensive toxicity testing and found to be safe (41). In human volunteer
 studies (38, 39), enteral nutrition products supplemented with Benefiber 20 g/L found to be
 safe. Two clinical trials (36, Alam et al., unpublished data) in children have been performed
 in ICDDR,B recently - in one study ORS was supplemented with Brenefiber 20 g/L and in other
 study comminuted chicken-based diet was supplemented with Benefiber 20 g/L. No adverse
 effects have been noted in these studies. In the proposed study, Benefiber will be
 supplemented with ORS either 25 g/L or 50 g/L for the treatment of adult cholera. As the
 cholera patients have profuse watery stools with short transit time, 50% of fibers are
 expected to excrete through stool unchanged. As the treatment of cholera is for a short
 duration (2-3 days), so we do not anticipate any adverse effects.
Inclusion Criteria:

 -  Age: 15 - 55 years

 -  Gender: Male (women would be excluded due to difficulties in separation of their urine
 from stools, particularly in those with severely dehydrated and associated mental
 obtundation).

 -  Duration of diarrhoea: 24 hours or less

 -  Clinical signs and symptoms of severe dehydration.

 -  Demonstration of V. cholerae in dark-field microscopy of a fresh stool specimen

 -  Written informed consent for participation in the study (for patients with temporary
 inability to provide consent due to their severe dehydration and mental obtundation,
 initial consent would be obtained from their attendants; however, the consent process
 would be re-applied to the patients when they are fully oriented)

 Exclusion Criteria:

 -  Chronic or iatrogenic diarrhoea

 -  Dysentery (presence of visible blood in stool)

 -  History of receiving antimicrobial or antidiarrhoeal drugs prior to admission

 -  Presence of concomitant infection or underlying disease, which might complicate
 diagnosis and/or assessment of response to study interventions

 -  History of renal or hepatic dysfunction

 -  Failure to obtain informed consent