In a recent study published in the journal Dr nutrients, Researchers have investigated the relationship between coffee consumption and irritable bowel syndrome (IBS) risk.
Study: Examining the association between coffee consumption and risk of developing irritable bowel syndrome: a systematic review and meta-analysis. Image Credit: Kingmaya Studio/Shutterstock.com
IBS and the benefits of coffee
IBS is a common disorder that affects the gastrointestinal tract and is characterized by abdominal discomfort, diarrhea, constipation and bloating. Current estimates indicate that IBS affects 5-10% of the world’s population. IBS is associated with significant harm, both in terms of quality of life and socioeconomic status of affected individuals.
Eating or avoiding certain food items has been shown to worsen or improve IBS symptoms in many individuals. For example, a Mediterranean-style diet, rich in fresh fruits and vegetables, whole grains, seeds, and nuts, has been consistently shown to alleviate IBS symptoms and improve overall health outcomes.
After water, coffee is the second most consumed beverage in the world and the most popular daily drink. Umbrella reviews on coffee consumption have revealed that three to four cups daily provide the best overall health results. Despite numerous studies investigating the link between coffee consumption and IBS, the results remain inconclusive and often misleading.
Coffee contains several bioactive molecules that have been hypothesized to interact with the gut microbiome, alter gut permeability, promote bile acid metabolism, and even improve central nervous system (CNS) function.
About the study
The current study aimed to evaluate the association between coffee consumption and risk of subsequent IBS development. The researchers used a systematic review and meta-analysis method in compliance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.
Data were collected up to March 31, 2023 from studies retrieved from the EMBASE, PubMed, and Cochrane Library databases. Inclusion criteria included publications that reported an association between coffee consumption and IBS, were randomized control trials (RCTs), case-control investigations, and cross-sectional studies, and published in English.
Publication year, geographic study location, study population demographics, and clinical outcomes were extracted from all studies. All extracted data were processed through double coding to verify and ensure accuracy.
Outcomes were quantified using standard deviation (SD) values reported for continuous variables and percentages or frequencies for categorical variables. Publication bias was assessed using the Newcastle-Ottawa Scale (NOS).
Statistical analysis included calculation of odds ratios (ODs), the results of which were pooled. Egger’s regression was used to report publication bias and interpret results where applicable.
A total of 187 studies were identified, of which eight met the inclusion criteria for the meta-analysis. The study has a total sample group of 432,022 individuals. Assessment of study bias revealed a moderate to high risk of bias, which was highest in selected cross-sectional studies.
The selected studies consisted mainly of cohorts from Asia (n = 6) with one each from Africa and the United Kingdom, respectively. IBS diagnoses in the included studies followed the ROME III criteria for IBS symptoms, with one exception that ROME II used. Levels of coffee consumption varied between studies, with some reporting binary study designs of drinkers versus abstainers, while others had more detailed cohort allocation.
A fixed effects model revealed that across included studies, coffee consumers were less likely to develop IBS than their abstainer counterparts with an OR of 0.84. Stability analyzes verified that these results held true across the 432,022-strong sample size despite differences in study-specific methods.
The current study used a fixed effects meta-analysis model to investigate the association between coffee consumption and subsequent IBS risk. The analyzes included eight studies spanning three continents with a sample size of more than 432,000.
The study results revealed that any amount or frequency of coffee consumption was associated with a reduced risk of later developing IBS.
Future research in this area should (1) prioritize high-quality prospective cohort studies with well-documented coffee consumption (and exposure) and track the development of incident IBS in previously healthy individuals over time and (2) investigate biological mechanisms. .”
- Lee, JY, Yau, CY, Loh, CY, etc (2022). Examining the association between coffee consumption and the risk of developing irritable bowel syndrome: a systematic review and meta-analysis. nutrients 15(22). doi:10.3390/nu15224745