Urinary biomarkers of meat consumption.

BACKGROUND Meat intake has been positively associated with incidence and mortality of chronic diseases, including diabetes, heart disease, and several different cancers, in observational studies by using self-report methods of dietary assessment; however, these dietary assessment methods are subject to measurement error. One method to circumvent such errors is the use of biomarkers of dietary intake, but currently there are no accepted biomarkers for meat intake. METHODS We investigated four analytes (creatinine, taurine, 1-methylhistidine, and 3-methylhistidine) specifically found in meat and excreted in urine. Twenty-four-hour urine samples were collected from 17 individuals on controlled diets containing varying levels of meat: vegetarian (0 g/d), low red meat (60 g/d), medium red meat (120 g/d), and high red meat (420 g/d), as part of two randomized crossover feeding studies. RESULTS When compared with the low red meat diet or the vegetarian diet, the urinary levels of all four analytes were significantly higher in urine samples collected after 15 days of a high red meat diet (P < 0.0001). Only urinary 1-methylhistidine and 3-methylhistidine were statistically significantly different for every diet type, increasing as the amount of meat in the diet increased (P < 0.01 for 1-methylhistidine and P < 0.05 for 3-methylhistidine). Furthermore, urinary excretion of 1-methylhistidine and 3-methylhistidine elevated with increasing meat intake in every individual. CONCLUSION Urinary 1-methylhistidine and 3-methylhistidine may be good biomarkers of meat intake. IMPACT To determine the public health impact of red meat on cancer risk, biomarkers are crucial to estimate true intake; these potential biomarkers should be further investigated in free-living populations.