Dietary Fiber Consumption and Gastrointestinal Health in Elderly Males: A Systematic Review

Background Gastrointestinal (GI) problems—particularly constipation—are common in older adults and lead to reduced quality of life, polypharmacy (laxative use), and increased healthcare utilization. Dietary fiber is widely recommended to improve bowel function and overall GI health, but the strength and specificity of evidence for elderly males remains unclear.  Objective To systematically review randomized controlled trials (RCTs), observational studies, and existing systematic reviews/meta- analyses assessing the effects of dietary fiber (food-based and supplemental) on GI outcomes in older men (≥60 years), and to identify gaps and practical recommendations.  Methods Electronic searches of PubMed/Medline, Embase, Cochrane Library and clinical-trial registries were performed (through 2025). Eligible studies included RCTs, cohort studies, and systematic reviews that reported GI outcomes (stool frequency, stool consistency, constipation prevalence/severity, laxative use, fecal transit time, GI symptoms, microbiota outcomes) in older adults, with subgroup data for males if available. When sex-specific data were absent, findings for older adult populations were considered and sex-data reporting quality was evaluated.  Results The evidence supports that increased total dietary fiber (and fiber supplementation, particularly psyllium) improves stool frequency and consistency and reduces constipation in older adults, with recommended intakes around ≥25 g/day for optimal laxation in many guidelines. Psyllium and other soluble fibers at doses >10 g/day over ≥4 weeks show consistent benefit for chronic constipation outcomes. Fiber interventions can reduce laxative reliance and favorably modulate gut microbiota, though heterogeneity exists across fiber types, doses, and study populations. Direct evidence specifically addressing elderly males is limited because many trials either enroll mixed-sex cohorts or do not report sex-disaggregated outcomes.  Conclusions Dietary fiber is an evidence-based, low-cost strategy to improve GI function in older adults and likely benefits elderly males similarly to mixed older populations. However, sex-disaggregated RCTs and mechanistic studies in elderly men are lacking. Recommendations: prioritize a food-first approach aiming for ~25 g/day total fiber (gradual increase with adequate hydration), consider psyllium supplementation (when needed) at clinically studied doses, and monitor for bloating or drug–fiber interactions. Future research should report sex-stratified outcomes and evaluate long-term impacts on quality of life and healthcare use.