Analysis: cosmetics developers are trying to harness the link between bacteria and healthy skin to create new skin care products

Biome skin sprays, prebiotic cleansers, probiotic shampoos; if you read skincare labels you may have noticed this growing trend. Cosmetics manufacturers are starting to market products claiming to "rewild" our skin, just as the food industry is promising to create flourishing biome gardens in the gut. 

There is growing evidence to support the idea that bacteria in our intestines are essential for digestive health. Now, many cosmetics developers are attempting to harness the relationship between bacteria and healthy skin. New skin care products containing probiotics (bacteria) or prebiotics (food for bacteria) claim a multitude of benefits from delivering healthier more radiant skin to treating conditions like acne, eczema and body odour. Research like mine may soon provide some answers about whether these products work or not. I study the gases (or odours) released from our skin to understand how they relate to health and disease. 

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Doctors have used smell to detect disease for a long time: ancient Greek and Chinese healers could diagnose infectious diseases like tuberculosis by smelling a patient's exhaled breath. Recent research has linked specific gases in breath with digestive health, where the gut flora is recognised as playing an important role. Consumer technologies for personal breath testing are emerging; such as Aire, the personal digestive tracker from the Irish company FoodMarble

Like breath gas testing, skin gas detection is non-invasive and could be a great screening tool. There are already examples of skin odours being linked to diseases, such as the unique odour associated with the sweat of people with chronic schizophrenia or the sebum of people with Parkinson’s disease.

Skin gases emanate from skin gland secretions (sweat and sebum) and from bacterial activity on these secretions. The mixture of gases released from skin can vary widely depending the type of glands and bacteria in a particular region. For instance, some bacteria on feet can breakdown sweat to release isovaleric acid, which is one of the major components of foot malodour. 

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Many other skin gases are present at levels below those detected by the human nose. Reports of canine olfactory detection of malignant melanoma and other cancers in humans is motivating new research to understand the link between skin gases and health.

My research at the Insight SFI Research Centre for Data Analytics in DCU is focused on understanding how the gases released from the skin glands and flora relate to skin health, particularly that of the skin barrier. The skin barrier refers to the outermost layer of skin which helps protect us from environmental irritants and pathogens and holds in moisture, preventing skin from drying out. The skin flora plays an important role in supporting the skin’s function as a protective barrier against pathogens. 

A strong skin barrier is one of the most important aspects of skin health. Some chronic skin diseases, such as eczema or psoriasis, are associated with skin barrier dysfunction, where normally smooth and supple skin becomes dry, irritated, inflamed and susceptible to infection. 

The life of the skin is deeply complex, diverse and sensitive to change

In my research, skin gas samples are collected by placing a small wearable device on the skin for a few minutes. This device contains a polymer material that acts like a sponge to collect the gases coming from the skin. Samples are then analysed in the lab using tools to separate all of the individual component gases. These gases are identified based on matching their properties with a database. 

Skin gas samples are complex and can contain external contributions (such as those from cosmetics and our environment) mixed with the gases derived from our glands and skin flora. The samples also vary widely depending on the skin site, skin flora, diet, environment and many other factors.

Despite this complexity, my research has established that skin gases can change when the skin barrier becomes damaged. These results are advancing my research to a clinical setting, where I’m interested in understanding skin gases in individuals with skin disorders associated with impaired skin barrier function. This research could improve our understanding of skin barrier disorders and support the development of sensors to track skin health status in the future. A wearable sensor could alert an individual to a change in skin barrier function, for example, so that they can act early to manage their skin health proactively. 

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Could this research also inform the development of topical cosmetics to boost the skin barrier and encourage the growth of "friendly" bacteria? It’s possible, but for now my research and that of many others involved in biochemistry all points in one direction: the life of the skin is deeply complex, diverse and sensitive to change. It would take a miracle cream to mimic that. 

The views expressed here are those of the author and do not represent or reflect the views of RTÉ