An analysis of small molecules called “metabolites” in a blood sample may be used to determine whether a person is following a prescribed diet, scientists at Johns Hopkins Bloomberg School of Public Health have shown.
Clinical trials of diets and their health impacts are often plagued by participants’ poor adherence to assigned diets, which can make it difficult or even impossible to detect the true effects of those diets. The new approach, described in a paper in the American Journal of Clinical Nutrition published on June 18, could provide an objective and relatively easy-to-obtain measure of dietary adherence, potentially greatly reducing the uncertainty of dietary intake estimates.
The Bloomberg School scientists demonstrated their approach by showing that the levels of dozens of metabolites in the blood differed significantly between treatment and control groups enrolled in a clinical trial of the blood pressure-lowering DASH (Dietary Approaches to Stop Hypertension) diet. The DASH diet emphasizes fruits and vegetables and restricts red meat, sodium and sweets.
“We can now consider these metabolites as candidate biomarkers for assessing adherence to the DASH diet in future nutrition research studies, and one day clinicians might use these markers to monitor what their patients eat,” says study lead author Dr. Casey M. Rebholz, an assistant professor in the department of epidemiology at the Bloomberg School.