The Effect of Fiber Supplementation on Chronic Constipation in Adults: An Updated Systematic Review and Meta-Analysis of Randomized Controlled Trials.

BACKGROUND: Chronic constipation is a prevalent disorder that remains challenging to treat. Studies suggest increasing fiber intake may improve symptoms, although recommendations on the fiber type, dose, and treatment duration are unclear. OBJECTIVES: We investigated the effects of fiber supplementation on stool output, gut transit time, symptoms, and quality of life in adults with chronic constipation via a systematic review and meta-analysis of randomized controlled trials (RCTs). METHODS: Studies were identified using electronic databases, backward citation, and hand searches of abstracts. RCTs reporting administration of fiber supplementation in adults with chronic constipation were included. Risks of bias (RoB) was assessed with the Cochrane RoB 2.0 tool. Results were synthesized using risk ratios (RRs), mean differences, or standardized mean differences (SMDs) and 95% CIs using a random-effects model. RESULTS: Sixteen RCTs with 1251 participants were included. Overall, 311 of 473 (66%) participants responded to fiber treatment and 134 of 329 (41%) responded to control treatment [RR: 1.48 (95% CI: 1.17, 1.88; P = 0.001); I2 = 57% (P = 0.007)], with psyllium and pectin having significant effects. A higher response to treatment was apparent in fiber groups compared to control groups irrespective of the treatment duration, but only with higher fiber doses (>10 g/d). Fiber increased stool frequency [SMD: 0.72 (95% CI: 0.36, 1.08; P = 0.0001); I2 = 86% (P < 0.00001)]; psyllium and pectin had significant effects, and improvement was apparent only with higher fiber doses and greater treatment durations (≥4 weeks). Fiber improved stool consistency (SMD: 0.32; 95% CI: 0.18, 0.46; P < 0.0001), particularly with higher fiber doses. Flatulence was higher in fiber groups compared to control groups(SMD: 0.80; 95% CI: 0.47, 1.13; P < 0.00001). CONCLUSIONS: Fiber supplementation is effective at improving constipation. Particularly, psyllium, doses >10 g/d and treatment durations of at least 4 weeks appear optimal, though caution is needed when interpreting the results due to considerable heterogeneity. These findings provide promising evidence on the optimal type and regime of fiber supplementation, which could be used to standardize recommendations to patients. The protocol for this review is registered at PROSPERO as CRD42020191404.

Further evidence to throw caution to the wind: outcomes using an assertive approach to manage refeeding syndrome risk.

BACKGROUND/OBJECTIVES: Refeeding syndrome (RFS) can occur in severely malnourished or starved populations that are provided with rapid or unbalanced nutrition. International guidelines recommend a cautious approach for managing RFS risk (hypocaloric nutrition for 4-7 days), however emerging evidence supports a more assertive approach. This study aimed to describe nutritional management and RFS-related adverse outcomes in patients at risk of RFS receiving care after implementing updated guidelines reflecting emerging evidence. SUBJECTS/METHODS: A retrospective cohort study of inpatients at risk of RFS during admission to a large metropolitan hospital in Queensland, Australia between November 2018 and April 2019 was conducted. Data were collected from medical records on nutritional management (provision of nutrition, electrolyte, and vitamin replacement) and outcomes (incidence of RFS, serum electrolyte decreases, hypo/hyperglycaemia, oedema, and organ function disturbance). Data were analysed descriptively; relationships between serum electrolyte decreases and nutrition management were explored using Fisher's Exact tests. RESULTS: Of the 70 patients identified at risk of RFS (58.4 ± 16.8 years, 56% male, 94% malnourished), majority of participants received required supplementation prior to the commencement of nutrition (thiamine: 76%; micronutrients: 72-100%; multivitamin: 61%) and a standard initial nutrition management plan (79%; cautious: 13%; liberal: 8%). There were no cases of RFS. Four participants experienced RFS-related adverse outcomes (severe electrolyte decreases: n = 2, hypo/hyperglycaemia: n = 2); however, there was no differences in serum electrolyte decreases based on the nutrition management plan (initial: p = 0.912; goal: p = 0.688). CONCLUSIONS: The implementation of more liberal RFS guidelines for the management of RFS risk appears to be safe. Further research examining liberalised refeeding protocols may be useful in updating international guidelines.