Source: Johns Hopkins University
Summary: Researchers found that by analyzing small molecules called metabolites in a blood sample, a scientist can determine if you’re following your prescribed diet or cheating.
Clinical trials are often plagued by participants’ poor adherence to assigned diets, which can make it difficult to evaluate the diets’ true effectiveness. The new approach in the could provide an objective and relatively easy-to-obtain measure of dietary adherence, greatly reducing uncertainty in dietary intake estimates. Scientists demonstrated the approach by showing that the blood levels of dozens of metabolites differed significantly between treatment and control groups in a clinical trial of the DASH diet, a treatment for high blood pressure. The diet emphasizes fruits and vegetables and restricts red meat, sodium, and sweets. The strategy used with DASH can determine patient adherence to other diets. The study findings were published in the American Journal of Clinical Nutrition.
Scientists and doctors traditionally assess dietary adherence in clinical trials and ordinary clinical practice by asking participants to keep track of what they eat. Human nature being what it is, however, self-reports are not always accurate. The research team decided to evaluate a potentially more informative and patient-friendly method based on blood samples. They demonstrated their approach using frozen stored blood samples drawn from participants during the landmark 1997 study of the DASH diet. That study found that DASH, compared with a control diet reflective of what the average American eats, significantly reduced blood pressure. The trial design, in which participants were provided with all study meals, ensured that dietary adherence was measured accurately meaning that the trial data could be used later to test new measures such as blood metabolites.
Asst. Prof. Casey M. Rebholz said, “One day, clinicians might use these markers to monitor what their patients eat” and further added, “We don’t think a single metabolite will be enough to detect a dietary pattern.”
More Information: Casey M Rebholz et al, Serum untargeted metabolomic profile of the Dietary Approaches to Stop Hypertension (DASH) dietary pattern, The American Journal of Clinical Nutrition (2018). DOI: 10.1093/ajcn/nqy099