Fine-scale Dietary Polyphenol Intake is Associated with Systemic and Gastrointestinal Inflammation in Healthy Adults.

ABSTRACT

BACKGROUND: Polyphenols are dietary bioactive compounds, many of which have anti-inflammatory properties. However, information on the intake of dietary polyphenols at the class and compound level and their associations with gastrointestinal (GI) and systemic inflammation is lacking. OBJECTIVE: Estimate dietary polyphenol intake in healthy adults and examine its relationship with GI and systemic inflammation markers. METHODS: Healthy adults (n = 350) completed the USDA Nutritional Phenotyping Study, an observational, cross-sectional study balanced for age, sex, and body mass index. Dietary intake, assessed via multiple 24-hour recalls, was ingredientized and mapped to FooDB, a comprehensive food composition database. Dietary polyphenol intake (total, class, compound) was estimated and examined for its relationship to GI and systemic inflammation markers using linear models and random forest regressions. RESULTS: Mean total polyphenol intake was approximately 914 mg/1000 kcal per day with flavonoids as the greatest class contributor (495 mg/1000 kcal per day). Tea, coffee, and fruits were among the largest food contributors to polyphenol intake. Total polyphenol intake negatively associated with the GI inflammation marker, fecal calprotectin (ß=-0.004, p=0.04). At the class level, polyphenols categorized as prenol lipids (ß=-0.94, p<0.01) and phenylpropanoic acids (ß=-0.92, p<0.01) negatively associated with plasma lipopolysaccharide-binding protein, a proxy for GI permeability. Food sources of these two classes included mainly olive products. We further detected a positive association between C-Reactive protein and polyphenols in the "cinnamic acids and derivatives" class using hierarchical feature engineering and random forest modeling. CONCLUSION: Even in healthy adults, dietary polyphenol intake was negatively associated with GI inflammation and intake of prenol lipids and phenylpropanoic acids were negatively associated with GI permeability. Relationships between polyphenol intake and inflammatory outcomes varied with the resolution - total, class, compound - of polyphenol intake, suggesting a nuanced impact of polyphenols on GI and systemic inflammation. CLINICAL TRIAL REGISTRY NCT02367287, ClinicalTrials.gov.