Outliers: We may have a nose for disease (and fat)

Look no further than the end of your nose to detect some medical conditions, researchers say. Studies on the fascinating relationship between disease and smell are proving we shouldn't sniff at the talent of the unassuming snout.

“There may be early biomarkers for illness in the form of volatile substances coming from the body,” said an author of a new study in Psychological Science, which found humans may be able to smell sickness in someone whose immune system is highly active. Researchers said this response may act as a first line of defense, helping healthy individuals avoid contagion.

The National Institutes of Health doesn't make a stink about its list of nearly 20 diseases associated with unusual breath odors, but you may turn up your nose at a few of them. For example, bowel obstruction can cause breath to smell like feces, and chronic kidney failure can generate an ammonia-like odor.

Another new study from the Monell Chemical Senses Center suggests we may also be able to sniff out large amounts of dietary fats by breathing in their delectable aromas. It's not surprising that the nicer something smells, the more likely we are to want to eat it. As the U.S. continues to face an obesity epidemic, researchers hope identifying these odor molecules will lead to innovative ways of making healthy foods smell “more palatable.”

Research into our olfactory organs is proving over and over again to pass the smell test, but don't walk around with your nose in the air just yet. “Certainly we should use odor as an indication, but it's not going to be the only diagnostic medium a 21st century physician will use,” said George Preti, a scientist at Monell. Smelling a patient was pretty common in pre-World War II medicine, he said, but analytical instrumentation using sensors for routine screening is what experts hope for in the future.

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