What Is The Microbiome?

The microbiome is the community of microorganisms – bacteria, fungi, and viruses – that live on, and within, our bodies. We used to think of bacteria as gross, or mostly dirty and disgusting things that are to be eliminated and avoided. But research into the microbiome has shown that the vast majority of our microbiota (the members of our microbiome) are not only benign but crucial to our health. In fact, there is evidence that exposure to the right set of bacteria at the right time of development is essential for our immune system to develop properly so that we can avoid allergies, asthma, and a host of other inflammatory disorders.

The raft of research in interest in the microbiome had also led to a renewed interest in the benefit of probiotics and fermented foods, although these are mostly aimed at maintaining a healthy gut microbiome. From kombucha to kefir, and yogurt to sauerkraut, we are rediscovering the powerful benefits of naturally fermented foods.

Before the advent of microbiome research, we used to think that most of the bacteria in our body resided in our gut. While that is true, we now know that other parts of our body, such as our skin. In fact, the skin alone has multiple separate microbiomes – for wet, dry, and oily (sebaceous) regions of the skin within our body. The unique features of our ‘oily’ microbiome are why we only get acne on our face, chest, and back (more on that later).

Naturally, since our skin microbiome is very different from our gut microbiome, what’s good for the gut isn’t automatically good for the skin. So if you’re being sold yogurt to smear on your face, you’re probably better off just eating it. Your stomach will thank you, your face won’t. Even worse, the overwhelming majority of the ‘probiotic’ skincare products contain dead, ground-up yogurt bacteria (look for ‘lysate’ or ‘extract’ in the ingredients section) – this does less than nothing to maintain a healthy skin microbiome.

While different body sites have extremely different microbiomes, they do share some features. One common theme is the concept of diversity – strong, healthy microbiomes tend to be more diverse. The bacteria in the community form an ecological web, and generally the more diverse these bacteria are, the more resilient this web tends to be. Conversely, a lack of diversity in the microbiome makes it easy to disturb and susceptible to attack by a pathogen. You can think of your microbiome like a farm or a garden. If you only have one type of plant, then a pest can wipe out the entire farm. But if you have several crops or plants, then a single pest can’t wipe them out and they will be more resilient to damage.

Have more questions about the skin’s microbiome? Leave them in the comments for Dr. Yug Varma to answer below!