Intake of prebiotic fibers and the risk of laryngeal cancer: the PrebiotiCa study

Purpose To evaluate whether the intake of specific fibers with prebiotic activity, e.g., inulin-type fructans (ITFs), fructo-oligosaccharides (FOSs), and galacto-oligosaccharides (GOSs), is associated with laryngeal cancer risk. Methods Within the PrebiotiCa study, we used data from a case-control study (Italy, 1992-2009) with 689 incident, histologically confirmed laryngeal cancer cases and 1605 controls. Six prebiotic molecules (ITFs, nystose [FOS], kestose [FOS], 1F-beta-fructofuranosylnystose [FOS], raffinose [GOS] and stachyose [GOS]) were quantified in various foods via ad hoc conducted laboratory analyses. Subjects' prebiotic fiber intake was calculated by multiplying food frequency questionnaire intake by the prebiotic content of each food item. The odds ratios (OR) of laryngeal cancer for prebiotic fiber intake were calculated using logistic regression models, including, among others, terms for tobacco, alcohol, and total energy intake. Results The intakes of kestose, raffinose and stachyose were inversely associated with laryngeal cancer, with ORs for the highest versus the lowest quartile of 0.70 (95% confidence interval, CI 0.50-0.99) for kestose, 0.65 (95% CI 0.45-0.93) for raffinose and 0.61 (95% CI 0.45-0.83) for stachyose. ITFs, nystose and 1F-beta-fructofuranosylnystose were not associated with laryngeal cancer risk. Current smokers and heavy drinkers with medium-low intakes of such prebiotic fibers had, respectively, an over 15-fold increased risk versus never smokers with medium-high intakes and a five to sevenfold increased risk versus never/moderate drinkers with medium-high intakes. Conclusion Although disentangling the effects of the various components of fiber-rich foods is complex, our results support a favorable role of selected prebiotic fibers on laryngeal cancers risk.