Daily Archives: 8 June, 2012

Irritable bowel syndrome and gut bacteria

Evidence that gut bacteria could be causing IBS symptoms means treatment with antibiotics offers fresh hope for sufferers.

Irritable bowel syndrome was once the Loch Ness Monster of illnesses – a mystery that no one could quite fathom. If you had it, you might even have been told it was ‘all in your mind.’ And doctors weren’t much better informed. People who saw their GP with symptoms such as painful bloating, diarrhoea or constipation or both might have been told they may have IBS, but the diagnosis wasn’t much help as treatments were focused on alleviating symptoms and weren’t very effective. Now research published in medical journal Digestive Diseases and Sciences has confirmed that gut bacteria are directly linked to IBS, making antibiotics a potentially effective treatment.

While previous studies have suggested that bacteria are involved in the condition, this is the first time the link has been made using bacterial cultures – producing a definitive result. Using bowel culture samples, researchers from Cedars-Sinai hospital, Los Angeles confirmed that small intestinal bacterial overgrowth was far more prevalent in patients with IBS than those without; more than a third of IBS patients had the overgrowth, compared with only 10% of those who had not been diagnosed with the condition.

Irritable bowel syndrome

Irritable bowel syndrome

Patients who had diarrhoea-predominant IBS were even more likely to have bacterial overgrowth, with 60% having high levels of small intestinal bacteria. IBS hasn’t always been taken seriously as an illness, with many people, including some doctors, dismissing it as not being a ‘real’ problem. Patients’ symptoms were sometimes blamed on stress, on psychological problems or as a symptom of unhealthy eating.


But in the last 20 years or so the number of people diagnosed with IBS has risen to one in 10. This has been helpful in one respect: the more people who have it, the more difficult it is for others to dismiss it. IBS can have a profound effect on a person’s wellbeing; aside from making the simple act of eating a meal potentially painful, it also affects everyday life in other ways. Many sufferers feel reluctant to take part in social events because of the embarrassing and painful symptoms.

Now there is concrete evidence linking bacterial overgrowth and IBS, patients can be offered antibiotics. The same researchers have done clinical trials with an antibiotic that is only absorbed in the gut – rifaximin – that has been shown to dramatically reduce bacteria levels in the gut, alleviating the problems associated with IBS.

Low-fiber diet linked to heart disease

Adolescents who don’t eat enough fiber tend to have bigger bellies and higher levels of inflammatory factors in their blood, both of which are major risk factors for cardiovascular disease and diabetes, a new study has revealed.

The study of 559 adolescents age 14-18 from Augusta, Ga., showed they consumed on average about one-third of the daily recommended amount of fiber, said Norman Pollock, bone biologist at the Medical College of Georgia and the Institute of Public and Preventive Health at Georgia Health Sciences University.

“The simple message is adolescents need to eat more fruits, vegetables and whole grains,” Pollock, one co-author of the study, said.

“We need to push recommendations to increase fiber intake,” he said.

Only about 1 percent of the young participants consumed the recommended daily intake of 28 grams for females and 38 grams for males. The study appears the first to correlate dietary fiber intake with inflammatory markers in adolescents.

Better understanding the relationships and risks of diet, inactivity and obesity in children and adolescents is particularly critical at a time when about 1 in 3 is overweight or obese, Samip Parikh, another co-author of the study, said.

That’s nearly triple the rate since 1963, according to the American Heart Association.

Low-fiber consumers in the study were more likely to have more of the visceral fat found in and around major organs in their abdominal cavity.

The heart

The heart

They also tended to have higher levels of inflammatory factors, such as immune cells called cytokines, as well as lower levels of protective adiponection, a protein secreted by fat that helps the body use glucose and fight inflammation. Interestingly, adiponectin levels tend to drop when fat becomes excessive and obesity is generally considered a chronic inflammatory state.


Exactly how fiber helps stave off some of these unhealthy consequences is not completely clear, Parikh said.

Hypotheses include increased bulk in the stool causing digested food to spend less time in the gastrointestinal tract and the ability of fiber to improve insulin sensitivity, potentially reducing visceral adiposity.

More indirectly, fiber tends to speed satiety, potentially decreasing total food and caloric consumption, Parikh said. It may also help absorb and eliminate inflammatory factors.

While belly fat and high inflammatory factors are inexorably linked to bad consequences such as heart disease and often occur together, one did not directly cause the other in this instance, Pollock noted.

He was co-first author earlier this year of a study on the same group of adolescents that showed high-fructose consumption correlated with higher blood pressure, fasting glucose, insulin resistance and inflammatory factors as well as lower levels of cardiovascular protectors such as such as HDL cholesterol and adiponectin.

These dangerous associations were exacerbated by belly fat.

“There is some other mechanism (for increased inflammatory factors associated with low-fiber intake),” Pollock noted.