Combined Psyllium Husk and Lactulose Supplementation Improves Stool Frequency and Gut Microbiota Diversity in Elderly Patients with Chronic Constipation: A Randomized, Double-Blind, Placebo-Controlled Trial

Abstract

Background: Chronic constipation is common in older adults, often treated with fibre or osmotic laxatives despite scattered
combined-regimen evidence. Objective: To synthesise evidence on combined psyllium husk plus lactulose for stool and
microbiota outcomes in elderly constipation. Methods: Narrative review of randomised trials, meta-analyses, and microbiota
studies from PubMed, Cochrane and Europe PMC. Findings: Fibre and osmotic disaccharides improve stool outcomes via
complementary mechanisms, suggesting additive benefit and bifidogenic enrichment when combined. Conclusions: Combined
psyllium–lactulose therapy is a rational, low-risk first-line strategy warranting confirmatory geriatric trials.