Measuring gut microbes

Your guts are home to millions and millions of tiny bacteria, which make up your gut microbiome. Most of them are what you might call "good" bacteria, helping you to digest your food and stay healthy, but there's a huge range of different bugs, and each one of us has our own personal 'signature' of gut bacteria.

Researchers are getting very excited about our gut bugs, as they influence our immune systems and could hold the key to understanding many human diseases, and even lead to ways to treat or prevent them. This week, researchers in the US led by Jeffrey Gordon have published a new method for identifying the range of bacteria in the gut, through DNA sequencing. So far they've only used the technique to study a handful of people, but the results so far are fascinating.

Writing in the journal Science, the team found that the signature of different bugs in your gut is probably remarkably stable over many years, even though we're exposed on a daily basis to a huge number of different bacteria. The team also found that family members share quite a few types of bugs in common, suggesting that the colonisation by bacteria starts early in life and stays quite stable as time goes on.

Intriguingly, when a group of four unfortunate overweight volunteers went on a liquid-only, low-calorie diet for several weeks, the scientists found that their gut bacteria changed quite dramatically as they lost weight, with different types becoming more or less common.

The new findings help to reveal more about the murky bacterial world in your bowels, and provide a powerful new method for studying it. The researchers even suggest that an analysis of you personal bacterial signature - obtained from a poo sample - should be part of everyone's yearly medical checkup.