[Fiber in enteral nutrition: systematic review of the literature]

It has been suggested that adding fibre to enteral nutrition (EN) formulas may achieve a normalization of the gastrointestinal tract's functions by reducing the incidence of diarrhoea and constipation. However, this supposition is based on the demonstrated effect of fibre in natural feeding. There have so far been no firm recommendations on the use, amount or type of fibre that is most advisable in EN.

To establish the scientific evidence existing on the benefits gained by adding fibre to EN formulas compared with the use of fibre-free formulas.

Bibliographical search on PubMed, on the register of Randomized Prospective Trials (RPT) of the Cochrane Library and manual search.

RPT comparing fibre-free formulas with isocaloric ad isonitrogen formulas containing fibre in total EN. Four independent reviewers revised the references selected. The data were analyzed using the RevMan 4.1 programme from the Cochrane Library.

Of 286 references, 25 fulfilled the inclusion criteria. The data were grouped by population and outcome variable. The addition of fermentable fibre to the EN formulas tends to reduce the incidence of diarrhoea in critically-ill and post-surgery patients (OR = 0.66; 95% CI 0.46-0.95; p = 0.19). The use of formulas with insoluble fibre seems to increase the frequency of depositions and reduce the need for laxatives in immobilized patients receiving long-term EN but the data are insufficient. In people with normal gastrointestinal functions, the frequency of depositions is similar when using formulas with and without fibre (DPM = -0.97; 95% CI -0.12-[-0.02]; p < 0.0001).

There is currently insufficient evidence to recommend the systematic use of formulas containing fibre in total EN. However, in critically-ill and post-surgery patients, the use of formulas with fermentable fibre tends to reduce the incidence of diarrhoea. Although information is still lacking. The formulas with insoluble fibre seem to diminish constipation in chronic EN, whereas in other situations where the digestive system is working appropriately, no benefit has been shown. It is necessary to increase the number and quality of these trials in order to be able to establish firm recommendations on the use of EN formulas containing fibre.