Dietary intake of fibers: differential effects in men and women on perceived general health and immune functioning

Background: It has been reported previously that dietary fiber intake provides health benefits. Nevertheless, only a limited number of human studies have investigated whether gender differences exist in the relationship between fiber intake and perceived health and immune status. Objective: To investigate potential gender differences in the effects of dietary fiber intake on perceived health and immune status of healthy young adults. Design: A survey was conducted among university students in Utrecht, the Netherlands. Data were collected on perceived general health status and perceived immune functioning. Dietary intake of fibers was assessed using a food frequency questionnaire. Perceived general health status and immune functioning were associated with daily intake of fibers using nonparametric (Spearman) correlations. Statistical analyses were conducted for the group as a whole, and for men and women separately. Results: N = 509 subjects completed the survey. Mean (SD) age was 20.8 (2.6) years old. 71.9% of the samples were females. Mean daily dietary fiber intake was 15.5 (6.9) g. Daily dietary fiber intake correlated significantly with general health rate (r = 0.171, p = 0.0001) and perceived immune functioning (r = 0.124, p = 0.008). After controlling for total caloric intake, the partial correlation between fiber intake and general health remained significant (r = 0.151, p = 0.002). In men, dietary fiber intake correlated significantly with perceived general health status (r = 0.320, p = 0.0001) and immune functioning (r = 0.281, p = 0.002). After controlling for caloric intake, the association between dietary fiber intake and perceived general health (r = 0.261, p = 0.005) remained significant. Remarkably, no significant correlations were observed in women. Conclusion: A significant association between daily dietary fiber intake and perceived general health status and immune rate was found in men, but not in women. Future studies should further address the nature and causes of the observed gender differences, including validated biomarkers for immune responsiveness. Abbreviations: FFQ: Food frequency questionnaire; GIT: Gastrointestinal tract; NCDs: Non-communicable diseases; SCFA: Short-chain fatty acid.