Chemical signature in belly button may reveal health indicators

Researchers have found that volatile compounds accumulating in the belly button are more than just leftover skin and sweat, suggesting they may carry a chemical signature linked to a person's health.

The navel naturally collects dead skin cells, sebum (oily secretions), and sweat, along with various types of bacteria that feed on these substances. This mixture produces a range of volatile organic compounds—molecules that easily disperse in the air—which can change depending on what is happening inside the body.

According to the research website Science Alert, a scientific team has shown that these compounds could be used to detect patterns associated with certain diseases by analyzing samples taken from the belly button and other body areas. The study involved 24 participants: six with Parkinson's disease, six with mild cognitive impairment, six with COVID-19, and six healthy individuals for comparison.

Researchers collected swabs from three sites on each participant: inside the nose, the concha of the ear (the hollow part of the outer ear that gathers sound and directs it into the ear canal), and the belly button. These areas were chosen because they are relatively less exposed to perfumes, soaps, and other substances that might affect the compounds found on the skin's surface.

As reported by Science Alert, the researchers analyzed the volatile compounds from the swabs using a technique called laser-based optoacoustic spectroscopy. This method measures how different molecules absorb infrared light, allowing the creation of a spectral fingerprint for each sample. The team then used statistical analysis to compare these fingerprints and determine whether samples from people with the same condition showed similarities.

The results showed differences between the groups, most notably in the nose and belly button samples. In the belly button samples specifically, there was a clear distinction between healthy individuals and those with mild cognitive impairment. However, samples from participants with Parkinson's disease and COVID-19 were not as clearly separated from the other groups, with some overlap in the results. This means the technique could not fully distinguish between all conditions.

To see if the pattern observed in Parkinson's patients would recur, the researchers took swabs from three additional people with the disease two weeks later. These samples closely matched the results from the initial Parkinson's group, suggesting the pattern was not just related to the timing of sample collection. However, the small number of participants means these findings alone are not enough to confirm the consistency of the pattern.

Science Alert also reported that the researchers found just five wavelengths might be sufficient to distinguish the patterns observed in the study. This could eventually allow for the development of smaller, simpler devices to analyze these chemical signatures. However, the technique cannot currently be considered a diagnostic tool. The small sample size makes it difficult to know whether the differences detected were due to the diseases themselves or other factors, such as age.

The experiment was also conducted under controlled laboratory conditions, while perfumes, soaps, personal care products, and environmental factors could affect the compounds present on the skin and in the belly button.

The researchers concluded that their results represent an initial step in demonstrating the potential of using volatile body compounds as health indicators. However, larger studies with age-matched groups and more realistic conditions are needed before this approach could become a practical diagnostic tool.