Plasma concentrations of anserine, carnosine and pi-methylhistidine as biomarkers of habitual meat consumption.

Dietary intake of red and processed meat has been associated with disease risk. Since dietary intake assessment methods are prone to measurement errors, identifying biomarkers of meat intake in bio-samples could provide more valid intake estimates. We examined associations of habitual red and processed meat, poultry, fish, and dairy products consumption with plasma concentrations of anserine, carnosine, pi-methylhistidine (Π-MH), tau-methylhistidine (T-MH), and the ratio of T-MH to Π-MH in a cross-sectional study. Plasma anserine, carnosine, Π-MH, and T-MH concentrations were measured using ion-pair LC-MS/MS in 294 participants in the second Bavarian Food Consumption Survey (BVS II). Habitual food consumption was assessed using three 24-h dietary recalls. Associations between plasma metabolites concentrations and meat, fish, eggs, and dairy products consumption were assessed by fitting generalized linear model, adjusted for age, sex, and BMI. Total meat intake was associated with plasma concentrations of anserine, carnosine, Π-MH and, the ratio of T-MH to Π-MH. Red meat intake was related to carnosine (p-trend = 0.0028) and Π-MH plasma levels (p-trend = 0.0493). Poultry (p-trend = 0.0006) and chicken (p-trend = 0.0003) intake were associated with Π-MH. The highest anserine concentrations were observed in individuals consuming processed meat or turkey. For T-MH we did not observe any association with meat intake. Our results indicate an association between habitual meat consumption and plasma concentrations of anserine, carnosine, Π-MH and the ratio of T-MH to Π-MH. Intervention studies should clarify whether the analyzed plasma metabolites are indicative for a specific type of meat before proposing them as biomarkers of habitual meat intake in epidemiologic studies.