11 things you didn't know about the microbiome
The human microbiome consists of bacteria residing in the gut and other body sites, but it also includes an abundant variety of other micro-organisms, from fungi and viruses to less familiar names, such as protists and archaea.
The composition of the microbiome can vary greatly from culture to culture, and indeed from person to person and body site to body site, but we know the most about the composition found in the healthy human gut. This community is dominated by bacteria of two phyla – Bacteroidetes and Firmicutes. These make up around 80 to 90 per cent of our total microbiota.
You might imagine that the acidic environment of the stomach is an inhospitable place, but acid holds little fear for many types of bacteria. Lactobacillus strains, for instance, create lactic acid as part of their normal operation.
While your gut contains the most abundant and diverse population of bacteria, you host a variety of microbial life across your entire body, particularly on the skin, in the mouth and in the urogenital tract.
The term ‘microbiome’ is a relatively recent invention, but early glimpses of the idea date back to the 1860s, when Antonie van Leeuwenhoek used a specially designed microscope to observe the diversity of bacteria resident in and on his body.
Many external factors can influence microbiome diversity. Antibiotics operate by reducing the reproduction of harmful bacteria, but can deplete populations of useful bacteria in the process. Stress can also alter the makeup of the microbiome, lowering numbers of potentially beneficial Lactobacillus bacteria. Fibre provides fuel to the bacteria of the gut, so a diet low in fibre and high in processed foods can be detrimental to microbiome health.