No Associations Between Dairy Intake and Markers of Gastrointestinal Inflammation in Healthy Adult Cohort

Abstract

ObjectivesWe examined associations between reported dairy intake and markers of gastrointestinal (GI) inflammation in a healthy human adult population. We hypothesized there would be a negative association of yogurt intake with GI inflammation, suggesting a protective effect, and no associations of total dairy, fluid milk, and cheese intake with GI inflammation. MethodsParticipants completed up to 3 unannounced 24-hour dietary recalls using ASA24 and a Block 2014 Food Frequency Questionnaire (FFQ) to assess recent and habitual intake, respectively. Those who also provided a stool sample were included in this analysis (n = 342). Stool samples were stored on ice immediately after collection and homogenized within 24 hours. Inflammatory markers from stool, including calprotectin, neopterin, and myeloperoxidase were measured by ELISA along with LPS-binding protein (LBP) from plasma. Regression models tested associations between dairy intake variables and inflammatory markers with and without covariates: sex, age, and body mass index (BMI). As yogurt is episodically consumed, t-tests were used to examine differences in inflammatory marker levels between consumers (>1 cup per month reported in FFQ) and non-consumers. Each dairy variable was also expressed as a percentage of mean energy intake from 24-hour recalls and regressed with inflammatory markers. ResultsWithout covariates, we found no associations between total dairy, fluid milk, and yogurt from both dietary assessments with any inflammatory markers. Cheese intake reported in the FFQ was positively associated with plasma LBP (P = 0.02). However, this association was not significant after covariate adjustment. There were no significant differences in GI inflammatory marker levels between yogurt consumers and non-consumers (P > 0.05). When expressed as a percentage of mean energy intake, cheese from ASA24 was associated with increased LBP (P = 0.03), but this was not significant after adjustment for covariates. There were no other associations of dairy variables as a percentage of energy intake with GI inflammatory markers. ConclusionsWe found no clinically relevant associations between dairy intake and markers of GI inflammation in a healthy human adult cohort. Funding SourcesCalifornia Dairy Research Foundation, USDA ARS 2032–51,530-026–00D.