Obesity risk can be determined through a newly-developed urine test, according to researchers at the Imperial College in London. This finding could lead to a new means of predicting obesity in patients before it appears.
Over 2,000 human urine samples were examined by researchers, who identified metabolites present in the waste product. These chemicals are byproducts of various body processes, including digestion. Pee samples were taken over two days, spaced three weeks apart. This allowed investigators to examine how specific metabolites correlated to diet, exercise, and other daily activities. The study identified 29 varieties of metabolites that correlate to body-mass index (BMI), commonly utilized as a measure of obesity.
Metabolites are not waste products, although they are found in urine. The chemicals can reveal which food have recently been consumed by the subject. As an example, the metabolite proline betaine will be detected in the urine of a person who has recently consumed a significant amount of citrus fruits. Concentrations of other metabolites change more slowly over time, and researchers examined how these correlated with diet and exercise choices.
"The kidney doesn't want those things at that particular moment. But nonetheless, a lot of metabolites that are in [urine] are still very useful to the body," Jeremy Nicholson, leader of the National Phenome Center at Imperial College, said.
Ratios between particular metabolites could reveal why some people burn calories more easily than others. As an example, the amino acid leucine breaks down into ketoleucine as skeletal muscles burn energy. This process appears to be more effective in people with greater concentrations of enzymes that assist in driving the change.
"You lose part of the ability to burn calories by not exercising because the enzymes that do it are turned off," Nicholson told NPR.
Future medical tests could examine these metabolites in patients, in order to determine if the subject could be at an elevated risk of obesity.
The thousands of frozen urine samples examined in the study are stored in a basement at Imperial College.
Around 78.6 million people - almost 35 percent of the U.S. adult population - is obese, according to the Centers for Disease Control and Prevention (CDC). The condition can lead to a host of medical problems, including diabetes and heart disease. Obesity costs Americans $147 billion dollars a year in lost productivity and medical costs, according to federal officials.
The idea that the leucine-to-ketoleucine ratio in patients could be indicative of obesity risk was first suggested in 1969. However, this was the first time that around half of the metabolites found to be correlated to the condition.
Analysis of how metabolites in urine may help predict obesity risk was profiled in the journal Science Translational Medicine.
Photo: Steven Depolo | Flickr
