The prebiotic effects of a new mixture of soluble fermentable fibres in the treatment of chronic constipation

Chronic constipation is a multifactorial polysymptomatic disorder very common in the western population. Though constipation is a widespread condition, its real prevalence and incidence are difficult to quantify because of the definition itself, which varies among physicians and laypersons, and because only a small part of people who perceive they have constipation seek health care. Chronic constipation has become a significant health problem, especially in the female population. It is associated with impairment of quality of life and high levels of psychological distress.1 A recent systematic review estimates the prevalence of constipation in Europe to be 17.1% (median value 16.6%) 2 and epidemiologic studies based on householder surveys in North America suggest a prevalence of 15% to 20% especially in people over 65 years old with a ten year cumulative incidence estimated at 17.4%.3-6 These prevalence rates were calculated using the Rome II criteria. However for self-reported constipation the prevalence rises up to 29.5% with approximately 1/3 of subjects dissatisfied with their bowel function.7-8 Idiopathic chronic constipation can be divided into slow transit constipation, outlet defecation syndrome and functional constipation but it is possible for different types to exist in the same patient with an overlapping of different subtypes. Many factors are implicated in the causation of chronic constipation: age, sedentary lifestyle, insufficient intake of fluid and fibre and a wide range of conditions such as medication, endocrine and metabolic disorders, neurological and gastrointestinal disease.9 Fibres are an important index of quality of a balanced diet.10 Epidemiological studies have suggested that there is a critical faecal wet weight of 160-200 gr/day for adults below which transit time falls.11 Using this critical faecal mass the adequate daily intake of dietary fibre ranges from 30 to 40 gr/day (14g per 1000 Kcal).12 Fibres are a wide variety of substances that belong to the family of carbohydrate and are not absorbed by the human digestive tract.13 High-fibre diet and prescription of fibre like bulking agents are very common in primary and secondary care management of constipation. Products with different types of fibres have been available for constipated people: wheat bran and dietary supplements with active ingredients like arabic gum, partially hydrolyzed guar gum, psyllium pectins, methylcellulose. In our study we decided to treat constipated patients with the association of gum arabic (GA) and fructo-oligosaccarides (FOS). GA is a soluble fermentable resin containig 85% of fibre obtained from the natural agricolture with a prebiotic effect favouring the growth of Bifidobacteria, Bacterioides and acidogenic bacteria.14 The GA is a dried exudate of the acacia tree (Acacia senegal), a tree commonly encountered in various tropical and subtropical regions of the world and prevalently in Sudan. It is a heteropolysaccharide of high molecular weight (approximately 350-850 kDa) containing galactose, rhamnose, glucuronic acid and arabinose residues and also minerals like calcium, potassium and magnesium.15 GA is a fermentable soluble substance with mechanical and metabolic effects: delaying gastric emptying, increasing faecal bulk and frequency of bowel movements, regulating colonic transit time, slowing glucose absorption from the small intestine with reduction of postprandial blood, serum total cholesterol and low density lipoproteins.16-19 The FOS and inulin when present in diet are the only short-chain carbohydrates prebiotics that had shown a significant increase in stool output in constipated patients, due to a modification of micro-organisms in the gut.20-22 The aim of our pilot study is to evaluate the effectiveness of an association between GA and FOS (FD Fibre Liquid, Dalco srl, Mirano-Venice, Italy) in the treatment of chronic constipation. The blend would combine effects of the soluble fibre with prebiotic effect of the short chain carbohydrate.