Developing Biomarkers of Dietary Intake

Studies of health and nutrition use a variety of tools to determine what people eat from day to day. Unfortunately, most of the methods used are not accurate for a variety of reasons and do not provide solid information on which to base health recommendations or public policy. In general, when people are asked to keep track of what they eat or recall what they have eaten in the past, they make mistakes in estimating both amounts and specifics of what was eaten. New tools that can help determine if people are accurately remembering what they ate are desperately needed. Biomarkers are things that can be measured (in urine, blood, hair, etc.) which are related to the intake of a particular food in a consistent way and may therefore be more accurate than a food record. One set of biomarkers that may be used are naturally occurring (present in all foods) stable isotopes of carbon and nitrogen to determine the relative amount of meat, fish, and soda (corn/sugar cane) in a person s diet. These isotopes can be measured in blood samples and hair. The aim of this study is to validate the use of stable isotope biomarkers as representative of specific dietary intake patterns (meat/fish/soda). This study will be an inpatient study in which highly specific diets will be fed to volunteers for \~12 weeks and stable isotopes will be measured in blood and hair. The ultimate goal is to develop biomarkers to be used to validate food intake patterns in outpatient clinical and epidemiological studies.