Gastrointestinal symptoms, faecal short-chain fatty acids and dietary intake in older adults: the Hordaland Health Study 3.

PURPOSE: Ageing is associated with a decline in gastrointestinal (GI) functions, but data on GI symptoms in older adults remain limited. This study assessed the prevalence of GI symptoms, irritable bowel syndrome (IBS), and faecal short-chain fatty acids (SCFAs) in older adults, and associations between GI symptoms and faecal SCFAs, dietary intake, and BMI. METHODS: 907 older adults (66-69 years, 50.7% females) from the community-based Hordaland Health Study 3 - Microbiota study were included. GI symptoms and IBS status were assessed by validated questionnaires (Gastrointestinal Symptom Rating Scale, Rome IV-criteria, IBS-Severity Scoring System), dietary intake by a 279-item food frequency questionnaire, and the concentration of SCFAs were measured from faecal samples. RESULTS: 33.9% experienced at least one GI symptom, 16.4% reported IBS-like symptoms, and 5.0% had IBS according to Rome IV-criteria. Indigestion was the most common GI symptom (24.2%). Females had a higher total mean score of GI symptoms (p = 0.021), with higher frequencies of constipation (p = 0.006) and abdominal pain (p = 0.031), compared to males. Males had higher concentration of total faecal SCFAs (p = 0.004) and all major SCFAs compared to females. Total faecal SCFAs were negatively associated with constipation, independently of dietary fibre intake, total energy intake, sex and BMI (B =  - 0.006, 95% CI [- 0.009, - 0.004], p < 0.001). We observed a positive correlation between total faecal SCFA concentrations and diarrhoea (r = 0.072, p = 0.039) and looser stool consistency (r = 0.185, p < 0.001); however, these associations did not persist in the regression analyses. All GI symptoms positively correlated with increasing BMI. CONCLUSION: GI symptoms are common in older adults, and IBS is at least as prevalent as observed in the general adult population. Improving dietary habits and preventing overweight and obesity may reduce the risk of GI symptoms and improve gut health in older adults.