On those bugs

around 10 to 15 percent better, but it is unclear if the bacteria changes as a result of someone becoming overweight or if the bacteria itself causes obesity. However, a study of mice found those who were given gut bacteria from obese mice put on more weight than those who got it from lean mice.

Nicholson says: “Interestingly, after someone goes through bariatric (obesity) surgery, their gut bacteria undergo a change. This surgery also acts as a virtually instant ‘cure’ for type 2 diabetes, and there is emerging evidence that gut bacteria are implicated with this, too.”

Bugs that help medicine work

Gut bacteria can determine the way we react to medication. “They metabolise drugs and change their absorption and toxicity,” says Nicholson. “Individual variations in bug activity change how drugs work – both good and bad effects are possible.”

This may help explain why people react differently to drugs – or why medication sometimes stops working for someone for whom it has previously been effective.

Could they ward off cancer?

Researchers are looking at whether gut bacteria – in particular Escherichia coli ( E coli) – are linked with colon cancer.

Dr Barry Campbell, a physiologist at Liverpool University, says some E coli strains can live harmlessly in the gut of healthy people, but problems arise when there is inflammation – which happens from time to time when the gut is damaged.

“This seems to reduce the numbers of beneficial bacteria and increase the presence of E coli,” he says. “We know inflammation increases the danger of cancer in the bowel, but we now believe inflammation increases the numbers and virulence of specific bacteria that support cancer development – it’s a whole new area of research.”

Key to babies’ immunity

During the first three months of pregnancy, the mother’s bacteria change to pass on beneficial bugs to her baby as it is born, according to a study published in PLoS ONE.

Strains such as Lactobacillus johnsonii — normally found in the upper gastric tract, where it helps with digestion – become abundant in the vaginal tract, while others decrease. During delivery, the baby picks up the bacteria, which is why babies born naturally have a mix of bugs often found in the gut while those delivered by Caesarean have a mix of bugs usually found on the mother’s skin.

The gut bacteria are thought to help prime the newborn’s immune system.

A recent US study at the Henry Ford Hospital in Detroit of 12 578 babies over two years found those born by Caesarean were five times more likely to develop allergies than those delivered naturally.

What you eat is important

Gut bacteria live on what is left of the food we digest and the remains of dead cells, so people’s Professoriles differ according to their diet, says Calder.

A 2011 study found children in Burkina Faso, West Africa – who have a diet low in animal protein and fat – had a different make-up of gut bacteria from those in Florence, Italy – who eat a diet rich in animal protein and sugar, and low in fibre.

“There is the possibility that by eating a diet higher in fat or carbohydrate, we can influence our health.

“The difficulty is identifying the type of bacteria present and their role,” says Calder.

“You can’t oversimplify it, as it seems to be the mix of bacteria that is important.” – Daily Mail