Sunday, January 29, 2012

When Bad Odors Happen to Clean People

Some people stink no matter how often they bathe. In August 2011 the American Journal of Medicine published a study of 353 people who had "malodor production" that couldn't be explained by poor hygiene, flatulence, or dental problems. They found that about one third of them tested positive for trimethylaminuria (TMAU), a genetically-transmitted disease that thwarts the body's ability to metabolize trimethylamine (TMA), a chemical compound common in eggs, some legumes, wheat germ, saltwater fish, and organ meats. When TMA is inadequately metabolized, it accumulates in urine, sweat, and saliva. The result is a gently radiating, fishy stench that is far from popular on the play-yard or at the water cooler.

TMAU was first identified as a disease in 1970, and the chemical test used to identify it is common. What is special about this study is that its researchers hail from the Monell Chemical Senses Center, a flavor lab in Philadelphia. Monell's team paid its usual heightened attention to aromatic nuance. What they found was a rich and varied TMAU bouquet. Because the disease is classified as rare (fewer than 200,000 affected individuals in the United States), typically doctors sniff for the characteristic fishiness before authorizing the chemical test. The researchers in this study suggest that, by doing so, they may be missing positive cases. Which is unfortunate because, once TMAU is identified, the odor problem can be solved. A diet hygienically "clean" of the foods carrying high TMA concentrations clears the air.