The specific smell emanating from the body can indicate what disease we have. In ancient times, when we were unwell, doctors used this method to diagnose diseases and treat us. For example, if a person’s breath had a sweet or fruity smell, then doctors would conclude that sugar was not being broken down in the digestive system and the person probably had diabetes. Science has since shown that the ancient Greeks were right.
In 1971, Nobel Prize-winning chemist Linus Pauling counted 250 different gaseous chemicals in breath. These gaseous chemicals are called volatile organic compounds or VOCs. Since Pauling’s discovery, other scientists have discovered hundreds more VOCs in our breath. We have learned that many of these VOCs have distinctive odors, but some have no odor that our nose can detect. Scientists believe that whether VOCs have any odor that our nose can detect or not, they can provide information about how healthy someone is.
Joy Milner diagnosed her husband with Parkinson’s due to his changed smell.
A Scottish man’s early onset Parkinson’s disease was diagnosed by his wife, a retired nurse (Joy Milner). That’s when she was convinced that her smell had changed years before she was diagnosed in 2005. This discovery initiated research programs involving Joy Milner to accurately identify the odor of this disease. Dogs can detect diseases by smell better than humans due to their more sophisticated olfactory ability. But analytical tools such as mass spectrometry capture even more subtle changes in VOC (volatile organic compound) profiles, which are being linked to gut, skin and respiratory diseases as well as neurological diseases such as Parkinson’s. Researchers believe that one day some diseases will be cured simply by breathing into a device.
Diseases can also be detected by the smell of skin, urine and stool.
Odor is not the only source of VOCs in the body. They are also excreted through skin, urine and feces. VOCs from the skin are the result of millions of skin glands removing metabolic waste from the body, as well as waste produced by bacteria and other microbes living on our skin. Sweat produces additional nutrients for these bacteria to metabolize, which can result in particularly odorous VOCs.
However, the odor from sweat makes up only a fraction of the VOC odor. The microbiomes of our skin and our gut are made up of a delicate balance of these microbes. Scientists believe they affect our health, but we don’t yet understand much about how this relationship works. Unlike the intestine, the skin is relatively easy to study. You can collect skin samples from living humans without going deep into the body. Scientists believe that skin VOCs may provide insight into how the bacteria in the microbiome and the human body work together to maintain our health and protect us from disease.
VOCs released from skin are different between men and women
Doctors are investigating whether a scent emitted from the skin can reveal various characteristics of the person to whom it is related. It is possible that signals from skin VOC signatures allow dogs to distinguish between people by smell. We are at a relatively early stage in this research area, but we have shown that you can differentiate between men and women based on how acidic the VOCs are from the skin. We use mass spectrometry to see this because the average human nose is not sophisticated enough to detect these VOCs.
Can estimate age with accuracy
We can also estimate a person’s age with reasonable accuracy within a few years from the VOC profile of their skin. This is not surprising because oxidative stress in our body increases as we age. Oxidative stress occurs when your antioxidant levels are low and causes irreversible damage to our cells and organs.
Our recent research found by-products of this oxidative damage in skin VOC profiles. These VOCs are not only responsible for personal odor, they are used as communication channels by plants, insects, and animals. Plants are in constant VOC communication with other organisms, including pollinators, herbivores, other plants, and their natural enemies such as harmful bacteria and insects. The VOCs used for this back and forth communication are known as pheromones.
Love pheromones being decoded
It is possible that humans also produce VOCs to attract suitable mates. Scientists have not yet fully decoded the other VOCs released from skin or our bodies. But the evidence so far for human love pheromones is controversial. One theory suggests that they were lost about 23 million years ago, when primates developed full color vision and began relying on their enhanced vision to choose a mate. However, physicians believe that whether human pheromones are present or not, skin VOCs can reveal who and how we are in terms of things like aging, nutrition and fitness, fertility, and even stress levels.