Newswise — A simple urine test may enable physicians to help improve their patients' overall diet quality, according to a paper being presented at the American Society of Nephrology's 39th Annual Meeting and Scientific Exposition in San Diego.
Despite the significant impact that diet quality has in reducing the risk of heart disease, stroke, cancer and total mortality, there is no simple, objective and inexpensive way for physicians to assess a person's diet in routine clinical practice. Current methods rely on asking individuals to report their typical eating habits through questionnaires or record their food consumption for several days or longer. These methods are time consuming, prone to inaccurate recall of dietary information and reporting bias, and do not meet the needs of practicing physicians.
Urine and blood tests have been known to offer alternative approaches to assessing an individual's diet. Thus, Andrew Mente of Prosserman Center for Health Research in Toronto and colleagues recently examined the use of urinary potassium as an alternative, clinically valid marker.
Dr. Mente and colleagues analyzed urinary potassium as a potentially useful clinical marker because foods promoted by current dietary guidelines are good sources of potassium. Evidence indicates a diet high in potassium reduces the risk of developing a broad range of health problems. Conversely, low amounts of potassium in the urine have been found to predict mortality in a Scottish population. Potassium in the urine strongly reflects potassium intake from the diet, and the daily intake of potassium is fairly constant, which makes estimating long-term dietary intake easier.
Mente and colleagues collected a single 24-hour urine sample from a total of 220 patients, aged 18-50 years, with kidney stones, from a population-based lithotripsy unit. The patients also completed food frequency questionnaires that assessed dietary intake over the past year. The researchers measured blood pressure, heart rate, weight and height, and calculated diet quality scores using a standard diet quality scale.
As urinary potassium increased, there was a steady and significant increase in diet quality score and the consumption of foods recommended by current dietary guidelines, as well as a steady decrease in body mass index, diastolic blood pressure, and heart rate.
"These findings suggest, for the first time, that the amount of potassium in the urine is a valid, objective indicator of diet quality," comments Dr. Mente. "This urinary marker is a simple, objective, universally available measure of diet quality that may aid physicians in providing effective dietary counseling. Physicians can now establish targets for therapy, monitor the effectiveness of dietary interventions over time, and provide effective dietary counseling to patients at risk because of poor food choices."
The study abstract entitled, "Urinary Potassium as a Clinical Marker of Diet Quality" (F-PO038) will be presented as part of a Poster Presentation on the topic of "Anemia and Outcomes" on Friday, November 17, from 10:00 am-Noon in Halls A/B/C of the San Diego Convention Center.
The ASN is a not-for-profit organization of 9,500 physicians and scientists dedicated to the study of nephrology and committed to providing a forum for the promulgation of information regarding the latest research and clinical findings on kidney diseases. ASN's Renal Week 2006, the largest nephrology meeting of its kind, will provide a forum for 10,000 nephrologists, to discuss the latest findings in renal research and engage in educational sessions relating advances in the care of patients with kidney and related disorders from November 14-19 at the San Diego Convention Center in San Diego, CA.
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