The skin – the largest organ of the body – acts as the body’s primary protective barrier and first line of defense against foreign invaders.
Without a strong protective outer skin barrier, your body becomes more susceptible to harmful microorganisms (known as microbial pathogens) and can also be triggered to call for an inflammatory response, which can lead to other unwanted effects in the body if not kept in check.
But how does the skin microbiome fit into this?
Well, in addition to our body’s own intrinsic defences that protect us against infection from microbial pathogens and disease, our resident skin bacteria also play a key role by helping to maintain a stable environment and regulate our immune system. Here we will explore this delicate relationship, as well as what happens in the event of skin microbiome imbalance.
Skin microbiome and immune protection
A healthy, balanced and fully functioning skin microbiome contributes to the barrier function of the skin and helps to maintain a stable skin surface environment, which protects against pathogens and helps mediate environmental stress. The skin microbiome also communicates with the body’s immune cells to influence their behavior, regulating immune responses and helping to keep your body stable and healthy
The Gut-Skin Axis
The gut appears to have a direct influence on the skin microbiome, via an intimate relationship known as the gut–skin axis, with the gut and its own microbiome now linked to skin health and homeostasis in numerous studies.
So, nourishing your gut with healthy foods such as whole foods, fibre and probiotics can help strengthen your skin. Short-chain fatty acids resulting from fibre fermentation in the gut, for example, can promote the growth of skin microbes that influence immune defence and regulate skin inflammation
Daily hygiene is a key factor that can modify the skin microbiome.
Handwashing and disinfectants, for example, have been shown to be effective in reducing pathogens on the hand. However, over-washing and excessive use of beauty and personal care items may negatively impact your skin microbiome by reducing the variety of microbes in our skin microbiome, or benefitting new and potentially harmful species.
The Skins pH
Our skin has a naturally acidic skin pH at 4.1–5.8  – and this should be considered when thinking about hygiene and personal care practices.
Cosmetic ingredients such as lactic acid, citric acid and sorbic acid that help maintain an acidic environment may also help support a healthy skin microbiome and in turn a healthy immune system.