Recently Science magazine published an interesting article describing the importance of keeping friendly flora (bacteria) on the surface of the skin to guarantee the best immune response from the epidermis against the attack of non-friendly bacteria. A similar situation and response takes place in the large intestine, where the flora plays an important role in the intestinal immune reaction against potentially harmful incoming bacteria.
In fact, experiments have shown that some common bacteria present on the epidermis are indispensable to the activation of cytokine production (cytokines are messengers involved in cell-to-cell communication) against foreign pathogens (microorganisms that produce disease).
Before we look at the implications involved in keeping a good, friendly flora on the skin, or the consequences of not doing so, we’d better go deeper into the explanation of what is a healthy skin flora.
The skin (which is the body’s largest organ), as well as the intestine, hosts many billions of friendly bacteria and fungi (saprophytes) that live peacefully and in harmony with it, contributing to its health and balance. This bacterial population is called the skin microbiome, or skin flora, and is not dangerous. We have around one thousand different species of bacteria on the skin – up to one million bacteria per square centimetre. Skin flora are usually non-pathogenic and can be either commensal – are not harmful to their host – or mutualistic (offer a benefit).
In addition to this stable, or resident flora, there are others, called transient flora: these are linked to the activities we do and to the various situations, both internal and external, the body faces on a daily basis.
All of these bacteria gather together in colonies, especially in the hair follicles or sebaceous glands, close to the orifices or in the most humid and warm areas of the body such as the armpits and groin.
They establish a mutual, synergetic collaboration with our skin, limiting or blocking colonisation from other pathogenic bacteria: this happens by competing for food (mostly sebum), resulting, as part of its breakdown, in a reduction of the skin’s pH value.
There are, of course, other preventative systems that fend off the attack of possibly pathogenic microorganisms, such as the integrity of the stratum corneum of the epidermis, and the immunoglobulin (present in sweating) reaction.
This is why it is so important to maintain good skin hygiene: when there is a scratch or a wound to the skin, the barrier to the penetration of potentially harmful bacteria in the skin or the blood is broken down, with infections as a consequence. A lack of defence can also occur when there is a reduced local immune response for various reasons, such as prolonged stress, bad lifestyle and diet, the suppression of the immune system or immune deficiency.
Moreover, antibiotics taken internally can alter not only the bowel flora but also the skin flora. If we view the body in a holistic way, we can see that whatever we do to one part of an organ will influence our whole body. This is one of the problems of modern medicine: it is very often focused on a specific situation or area of the body without considering the consequences for the whole system.
One interesting example of this is the bacterium Pseudomonas aeruginosa. Normally this is a mutualistic bacterium, but it can become aggressive and then, entering the blood stream, cause severe infection. Again this can happen if the condition of the skin and our general health changes. So its aggressiveness is only the expression of a general weakness. This bacterium produces a specific antimicrobial substance called pseudomonic acid that works against staphylococcal and streptococcal infections and, through other substances generated, inhibits the growth of fungi such as Candida albicans on the skin. So when we use antibiotics both internally and externally, we can alter the pseudomonas equilibrium and, as a consequence, get infections.
From this example we can see how everything is connected, and that in changing things or acting without gaining a wider vision of the body, we can experience quite different results; a kind of ‘butterfly effect’ is set off.
It is important to respect the skin’s delicate equilibrium and its microbiome and use non-aggressive, organic and chemical-free products. Chemical preservatives and antibiotics added to skin products to preserve them will ultimately alter the skin’s finely balanced natural chemistry, leading in time to possible allergies, inflammations and the skin complaints so common nowadays. The right products should respect the skin’s balance, its pH value and, acting in harmony with it, nourish it and promote the process of regeneration and repair.
As we supply the bowel with pre- and probiotics, especially after the use of antibiotics, in order to restore the balance of the microbiome, we should follow the Hippocratic Oath: first, do no harm to the skin and, if it is damaged for any reason, give the skin a prebiotic by using oil-based products rich in essential fatty acids.