How taking antibiotics can make you fat, ill and prone to auto-immune diseases

 By Jerome Burne

PUBLISHED:18:39 EST, 6  August 2012| UPDATED:19:31 EST, 6 August 2012


At first glance it sounds like an ad for  a dodgy herbal supplement.

Two years ago Chinese microbiologist Dr  Zhao Liping revealed at a U.S. conference how he’d lost 44lb (more than 3st)  simply by eating Chinese yam and bitter melon.

He said the foods had a beneficial effect on  the bacteria in his gut.

But what distinguishes Dr Liping’s  claims  from the quack remedies on the internet is that he is a respected scientist  whose work on the link between the ‘good’ bacteria that lives in our guts and  obesity has just been published in the top science  journal  Nature.

He is  just one of a number of scientists  whose work is painting a dramatic new picture of the health impact of the  billions of bacteria that call our  bodies home.

Keep  these bacteria in the right balance and  they can control weight, cut the risk of eczema in babies and keep old people  stronger, it seems.

It may even be possible to use beneficial  bacteria to switch certain genes on or off.

 If all this is true, it could be another very  good reason for avoiding antibiotics.

For years doctors have been cautioned not to  prescribe antibiotics like Smarties for every cough and cold, partly because  they have no effect on the viruses that cause these illnesses, but more  importantly because widespread use drives up resistance, leading to  superbugs

But now scientists believe excessive  antibiotic prescribing could be damaging our health more directly.

By wiping out our gut bacteria, they could be  making us ill, fat and prone to auto-immune diseases such as  eczema.

First to Dr Liping’s extraordinary  discovery.

Back in 2006, feeling ill and decidedly  portly, he came across a report that fat rats had different bacteria in their  guts compared with thinner rats.

‘The key player was a microbe called  F.Prausnitzii that was much lower in the fatties,’ he told the Mail.

Being a microbiologist, Dr Liping was able to  test a faecal sample to see how much F.Prausnitzii he had. There was almost  none.

He decided to see if it was possible to  repopulate his gut. But how to shift the balance?

‘There’s a lot of evidence that various foods  can encourage changes in gut flora,’ he says.

‘So I searched for a traditional  remedy.’

Keep the bacteria in our body in the right balance and  they can control weight

He came across Chinese yam and bitter melon,  which were used to treat diabetes and obesity in Imperial times.

As well as adding these to his diet, he also  switched to whole grains.

Soon the weight started dropping off and the  proportion of  F.Prausnitzii in his gut went up from undetectable levels to  a healthy 14.4 per cent, while his blood pressure, heart rate and cholesterol  all came down.

It seems something in the yam and melon  triggered the beneficial bacteria to multiply — this is known as a prebiotic  effect.

Since Dr Liping’s discovery, much larger  clinical trials have been run by his lab at the Shanxi Academy of Agricultural  Sciences in Taiyuan, China.

The first involved more than 100 obese young  men who lost an average of 15lb after just nine weeks on the prebiotic  diet.

A trial involving 1,000 obese patients  is now underway.

No one really knows how it works yet. It  could be that beneficial bacteria that respond to the yam and melon reduce the  amount of food absorbed in the gut.

But Dr Liping admits it’s not even clear  whether the bacteria actually cause the weight loss or just show up when the gut  is healthier.

For some years now researchers have shown  that giving the beneficial bacteria themselves — known as probiotics — can  prevent or treat diseases.

A recent report found a probiotic combination  halved the risk of eczema in babies.

It also cut their chance of developing  allergies to irritants such as pollen, house dust, milk and eggs.

Researchers at Swansea University gave either  a placebo, or a commercial brand of probiotics to 450 mothers for the last three  months of pregnancy and for the babies’ first six months.

After two years the risk of developing eczema  was down by 60 per cent and the chances of developing an allergy had dropped by  half.

‘Allergies are on the rise, affecting three  times as many youngsters as 20 years ago,’ says Professor Stephen Allen, who led  the study (which has just been submitted for publication in the Journal of  Allergy and Clinical Immunology).

‘We showed that there is something to be done  to cut the risk at a young age.’

It also raises the possibility that giving  regular courses of antibiotics to young children may do more harm than  good.

One of the first researchers to  pick this up was Martin Blaser, professor of internal medicine and  microbiology at New York University and an expert on the ulcer-causing bug  H.pylori.

Anyone infected with this usually gets an  intensive antibiotic course to kill it off.

But that may not be wise, says Professor  Blaser. It could be contributing to the obesity epidemic.

‘We’ve found that H.pylori is often one of  the good guys,’ he says.

‘Among other things it controls the hunger  hormone ghrelin that’s made in the guts.

‘When levels of ghrelin rise, you feel  hungry. Getting rid of H.pylori pushes up ghrelin production, although we don’t  know why yet.

‘Children get lots of antibiotics, and I’m  afraid that may be contributing to childhood obesity.’

H.pylori can also be a problem: it does cause  ulcers and has been linked with gastric cancer.

But other experts are beginning to question  whether knocking it out is always a good idea.

‘There is some evidence that  H.pylori  can protect against acid reflux (when stomach acid leaks into the gullet causing  heartburn),’ says Dr Ruchit Sood, specialist registrar in gastroenterology at  York Teaching Hospital.

‘It’s been increasing as H.pylori infection  has been declining.’

Heavy-handed use of antibiotics could also be  making children with the lung disease cystic fibrosis and elderly patients more  likely to develop infections, according to new research.

This isn’t because of growing resistance, but  because carpetbombing with antibiotics — as one researcher puts it — upsets the  balance of bugs in our guts.

‘We’ve been looking at the friendly microbe  population in kids with cystic fibrosis, and the number of species is right  down. Just a few dominate,’ says lead researcher Professor John LiPuma,  paediatrician at the University of Michigan.

‘There’s evidence a more varied bug community  is better at keeping the bad bacteria in check.’

Another study published in Nature found  something similar with elderly people.

Those living in the community had greater  variety in their gut’s bug population and had fewer infections than those in  care homes. They were also less likely to be fragile.

However, it hasn’t yet been shown that  boosting bacteria variety would reduce fragility.

Research such as this is already pointing in  a revolutionary new direction.

If friendly bacteria can influence our  weight, resistance to infection and strength in old age, maybe targeting and  tweaking their genes could bring major benefits.

This is the big idea of Professor Jeremy  Nicholson, a biomolecular researcher at Imperial College London.

‘Gut bacteria release chemicals that can  turn human genes on and off in beneficial ways,’ he says.

‘Finding ways to boost that effect could  result in new treatments.’

A good place to look, he suggests in a new  paper, is among the substances used in Chinese medicine.

Did the foods Dr Zhao Liping use in his  weight loss programme also have a beneficial effect on genes linked to weight  loss?

No one knows yet, but it’s an exciting  thought

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