How irritable bowel misery can be cured just by taking antibiotics
It helped Nicola and now scientists think many more could benefit too
NICOLA Hunter- Hostler has had a sensitive tummy for longer than she cares to remember. ‘I’ve never been regular,’ says Nicola, 43, a hairdresser. ‘Then, around 12 years ago, I started to sometimes get a low, dull pain on the right side of my stomach. It was very mild, and I just thought it was a bit of irritable bowel syndrome (IBS).’
However, five years ago, the pains got worse. Nicola, who lives with her husband, Matthew, in Ipswich, Suffolk, and has one son, also started to become very bloated whenever she ate.
‘It was the bloating that was the worst,’ she says. ‘I couldn’t understand it. Whatever I ate, I just seemed to balloon. A few times, I even had people ask when the baby was due.’
Nicola finally saw her GP about it, who agreed it might be IBS — characterised by pain, bloating and diarrhoea or constipation (or both).
Her symptoms continued, and Nicola developed chest and back pain whenever she ate. Two years ago, with her bloating and pain still unbearable, she felt achy and exhausted.
Painkillers and various alternative remedies didn’t help, and she started having to cancel appointments at work. She went back to her GP who, thinking it might be a gastrointestinal infection, prescribed antibiotics.
To Nicola’s surprise, within three days her symptoms improved. ‘It was like something had lifted,’ she says.
‘I had much less pain and bloating and just felt better — less fatigued and my mood improved. Unfortunately, over the next few months, my symptoms came back. I started wondering how it could be connected, and began looking into bacterial infections in the gut.’
That’s when she stumbled across an article on SIBO, or small intestinal bacterial overgrowth to give it its full name. It is a hot topic in IBS research.
It refers to an excessive growth of bacteria — or growth of the wrong type of bacteria — in the small intestine, which sits between the stomach and the large intestine. The small intestine is usually relatively sterile, because the muscular contractions that sweep through the digestive system after we eat keep it clean of bacteria.
However, as Professor Peter Whorwell, a gastroenterologist at the University Hospital of South Manchester NHS Trust, says: ‘If the motility of the small intestine is poor, you’ll get bacterial accumulation and it becomes extremely unhealthy.’
Typical symptoms of SIBO include pain, bloating and changes in bowel habit, thought to be caused by gas produced by the abnormal bacteria.
SIBO isn’t a ‘new’ condition: doctors have been taught about it as a problem in diabetes, which can cause damage to nerves that control the intestinal muscles.
And it’s also recognised as a complication of gastrointestinal surgery and inflammatory bowel conditions such as Crohn’s disease, as these can cause the gut to narrow and become clogged.
What is new is the idea that SIBO may lie at the root of many cases of IBS (which affects an estimated one in ten of us). IBS is normally diagnosed by taking a symptom history, and some tests may be performed to exclude conditions such as Crohn’s.
IBS has long been considered a problem of the large intestine, with symptoms thought to be caused by muscle spasms or an overly sensitive nervous system.
But research suggests that SIBO in the small intestine may be to blame for some cases, with antibiotics offering a solution.
Dr Mark Pimentel, a gastroenterologist at Cedars Sinai Medical Center in Los Angeles, who has been leading research in this field, recently published a study in the New England Journal of Medicine. It showed that IBS patients who took a two-week course of the antibiotic rifaximin reported significantly more relief from their symptoms than those taking a placebo.
Previous studies by Dr Pimentel suggest that between 40 and 80 per cent of people with IBS have positive breath tests for SIBO. But doctors in the UK have been more cautious in embracing this idea.
‘There is a lot of speculation that patients with IBS have a degree of SIBO — however, it’s controversial,’ says Professor Whorwell.
The controversy is partly down to the test for bacterial overgrowth, which involves measuring levels of hydrogen in a patient’s breath after they’ve consumed a sugar solution. The gas is produced by gut bacteria.
( Some doctors also test for methane, as this may provide further information.)
If hydrogen levels rise 30 minutes to an hour after taking the sugar solution — too soon for the food to have reached the large intestine — this is seen as evidence that you have bacteria in the small intestine, says Dr Jeremy Sanderson, a consultant gastroenterologist at Guy’s and St Thomas’ Hospital, London. He adds: ‘Sceptics have argued that these breath tests are just showing rapid transit of food to the colon, and that the hydrogen is coming from the bacteria there, rather than the small intestine.’
His view is that IBS is triggered by a mix of factors, with SIBO just one of these. He says: ‘SIBO is only there in a modest proportion of patients — a maximum of 20 per cent.’
Doctors are also wary about treating IBS with antibiotics because this could contribute to antibiotic resistance.
‘ On the other hand, we clearly have a group of IBS patients who take a course of it and feel better,’ says Dr Sanderson. ‘And when you look at breath tests, they do get this early rise in hydrogen — so it’s difficult to say there’s not something in this.’
While antibiotics offer temporary relief, many patients find that their symptoms return within a few weeks.
‘That’s likely to be because you haven’t got to the root cause of the SIBO,’ says Dr Sanderson.
So what might trigger it? The latest thinking is that many cases of IBS relate to a bout of gastroenteritis or food poisoning.
After the bug is gone, the antibodies that fought it off mistakenly start to attack the cells in the gut that control food movement — this slows down contractions. Dr Pimentel has developed a blood test for two antibodies associated with gastroenteritis, which he says can quickly diagnose irritable bowel caused by food poisoning and SIBO.
This year, writing in the journal PLOS ONE, he published a study of 3,000 people, which showed that those with IBS had significantly higher levels of these antibodies. Other studies suggest SIBO may be caused by low stomach acid as a result of stress or taking proton pump inhibitor medication (drugs to treat acid reflux).
Previous courses of antibiotics may also contribute by disrupting the balance of bacteria.
After Nicola saw an improvement with antibiotics, her GP referred her to a gastroenterologist who, after conducting an endoscopy (inserting a camera on a flexible tube through the mouth) and a colonoscopy (inserting a camera up the back passage) to rule out anything more serious, agreed that she probably had SIBO.
He said he could do a breath test, but the waiting time would be more than three months.
Nicola decided to see Tracey Randell, a nutritionist specialising in IBS, who gave her the breath test, which, she said, tested positive for SIBO.
Nicola believes her SIBO may be linked to antibiotic treatment she had years ago for sinusitis.
However, she is also a candidate for a striking new finding that SIBO may be linked to joint hypermobility, a genetic condition where the joints have an unusually large range of movement — sometimes referred to as being ‘double jointed’.
Nicola has suffered with painful joints on and off since her teens and, five years ago, was referred to a rheumatologist, who said she had joint hypermobility.
She had never imagined it could be related to her gut problems.
LAST year, a study of 552 people published in the journal Clinical Gastroenterology and Hepatology showed that gastrointestinal symptoms increased in correlation with severity of joint hypermobility.
‘It’s quite compelling,’ says Dr Sanderson, who is studying the link. ‘People with significant joint hypermobility will often complain of bloating IBS — lots of dancers have it, for example.
‘And the number of people coming through the door with IBS who are hypermobile is much more than the people who are not. It’s absolutely self-evident.’
The theory is that this condition may affect the motility of the gut, too — the collagen in the tissues of the gut may be the same as that in the ligament.
Under the supervision of her nutritionist, Nicola has made some changes to her diet, eliminating so- called highFODMAP foods — such as carbohydrates, some vegetables and fruit, dairy and artificial sweeteners — which are known to be fermented by gut bacteria.
There is compelling scientific evidence to show these are linked to IBS in some people.
Nicola says she began to feel better within weeks, although she has still not completely recovered. ‘I think the next step might be more antibiotics,’ she says.
But for now, she is simply relieved to have a name for her symptoms. ‘I was a mess and felt no one was able to help me,’ she adds.
‘I wonder how many other people are out there in the same position.’
NICOLA has set up a Facebook group for SIBO patients: visit facebook.com/SiboGroupUK