Chemical signature in belly button may reveal health indicators

Researchers have discovered that the volatile compounds accumulating in the belly button are more than just remnants of skin and sweat, suggesting they may carry a chemical signature related to human 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 and whose composition can change depending on what is happening inside the body.

According to the research website Science Alert, a scientific team revealed the potential to use these compounds to detect patterns linked to certain diseases by analyzing samples taken from the navel 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 concave part of the outer ear that gathers and directs sound into the ear canal), and the navel. These areas were chosen because they are relatively less exposed to perfumes, soaps, and other substances that could affect the compounds present on the skin's surface.

The researchers, as reported by Science Alert, 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. Statistical analysis was then used 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 navel samples. In particular, the navel samples revealed 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 other groups, with some overlap in results, indicating that the technique could not fully distinguish between all conditions.

To see if the pattern observed in Parkinson's patients was consistent, researchers took additional swabs two weeks later from three more people with the disease. The results were largely similar to those from the initial Parkinson's group, suggesting the pattern was not tied only to the timing of sample collection. However, the small sample size means these findings alone are not enough to confirm the pattern's reliability.

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

The experiment was also conducted under controlled laboratory conditions, whereas perfumes, soaps, personal care products, and environmental factors could influence the compounds found on the skin and in the navel.

The researchers concluded that their findings represent an initial step toward proving 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 can become a practical diagnostic tool.