Information adapted from Discover: Science for the Curious

MICROBIOME: YOUR BODY HOUSES 10X MORE BACTERIA THAN CELLS

“Your body is made up of around ten trillion cells, but you harbour a hundred trillion bacteria. For every gene in your genome, there are 100 bacterial ones. This is your ‘microbiome’ and it has a huge impact on your health, your ability to digest food and more. . . . Everything from the food we eat to the way we’re born influences the species of bacteria that take up residence in our bodies.” This slideshow is adapted from Discover : Science for the Curious. Image by David Gregory & Debbie Marshall, Wellcome Images

THE UNIVERSE OF US

“In a thorough survey of our skin microbiome, Elizabeth Grice identified species from at least 205 different genera. Your forearm has the richest community with an average of 44 species, while your nostril, ears and inguinal crease (between leg and groin) are the most stable habitats.”

THE ZOO ON YOUR SKIN

“The dark corridors of your intestine house more bacteria than any other part of your body. A team of international scientists led by Junjie Qin and Ruiqiang Li discovered that each of our bowels carries at least 160 bacterial species.”

BACTERIA WITH GUTS

“We inherit our microbiomes from our mother, picking up billions of them as we slide from her largely bacteria-free womb” through the birth canal. Babies who are born naturally have a different set of bacteria needed for digestion than those who are born via Caesarean section.

OUR ZEROETH BIRTHDAY PRESENT

The microbiome in our body is like another organ “helping us to break down foodstuffs that our own cells cannot cope with. And in turn, our food affects our microbiome.” Our first bacteria help us digest milk proteins. Our body activates new genes in the microbiome to “break

down the complex sugars and starches in plants, preparing us for the menu to come. As our diet diversifies, so do our bacteria.”

YOU ARE WHAT YOU EAT

Two groups of bacteria in your microbiome “Bacteroidetes and Firmicutes -could influence our body weight.”

There is a ratio between these two groups. The more fat that we have in our diets, the greater the number of Firmicutes in our microbiome. This ratio may influence the signals we receive that tell us we need to eat more than we do.

THE BACTERIA THAT MAKE YOU FAT

What happens in our gut can affect our brains. Research mice that were microbiome and germ free were found to be more active than those with a normal microbiome. The activity of microbiome-free mice returns to normal when mice receive bacteria through their diets.

GUTS TO BRAINS – HOW THE MICROBIOME SHAPES OUR MINDS

The bacteria of our microbiome are mostly our allies. But they can also they can be turned against us. Two new studies in mice have found that viruses - including one that causes polio, and another that causes cancer - can exploit gut bacteria to infect our bodies.

FROM ALLIES TO ENEMY COLLABORATORS