Extracts of broccoli and banana may help in fighting stomach problems, research suggests. Laboratory studies show fibres from the vegetables may boost the body's natural defences against stomach infections. Trials are under way to see if they could be used as a medical food for patients with Crohn's disease. Crohn's disease is an inflammatory bowel disease that causes symptoms such as diarrhoea and abdominal pain. It affects about 1 in 1,000 people, and is thought to be caused by a mixture of environmental and genetic factors. The condition is common in developed countries, where diets are often low in fibre and high in processed food.
Scientists at the University of Liverpool looked at how roughage from vegetables influenced the passage of harmful bacteria through cells inside the gut. They found that fibres from the plantain, a type of large banana, and broccoli, were particularly beneficial. But a common stabiliser added to processed foods during the manufacturing process had the opposite effect.
Dr Barry Campbell, from the University of Liverpool, said: “This research shows that different dietary components can have powerful effects on the movement of bacteria through the bowel. “We have known for some time the general health benefits of eating plantain and broccoli, which are both high in vitamins and minerals, but until now we have not understood how they can boost the body's natural defences against infection common in Crohn's patients. “Our work suggests that it might be important for patients with this condition to eat healthily and limit their intake of processed foods.”
The research, published in the journal Gut, and carried out in collaboration with experts in Sweden and Scotland, investigated special cells, called M-cells, which line the gut and ward off invading bacteria. Work was carried out in laboratory-grown cells and tissue samples from patients undergoing surgery for stomach problems. Clinical trials are now underway in 76 Crohn's patients to find out whether a medical food containing plantain fibres could help keep the disease at bay. “It may be that it makes sense for sufferers of Crohn's to take supplements of these fibres to help prevent relapse,” said Professor Jon Rhodes of the University of Liverpool.
Researchers employed imaging techniques to examine and analyze brain anatomical differences between 55 female IBS patients and 48 female control subjects. Patients had moderate IBS severity, with disease duration from one to 34 years (average 11 years). The average age of the participants was 31.
Investigators found both increases and decreases of brain grey matter in specific cortical brain regions.
Even after accounting for additional factors such as anxiety and depression, researchers still discovered differences between IBS patients and control subjects in areas of the brain involved in cognitive and evaluative functions, including the prefrontal and posterior parietal cortices, and in the posterior insula, which represents the primary viscerosensory cortex receiving sensory information from the gastrointestinal tract.
“The grey-matter changes in the posterior insula are particularly interesting since they may play a role in central pain amplification for IBS patients,” said study author David A. Seminowicz, Ph.D., of the Alan Edwards Centre for Research on Pain at McGill University. “This particular finding may point to a specific brain difference or abnormality that plays a role in heightening pain signals that reach the brain from the gut.”
Decreases in grey matter in IBS patients occurred in several regions involved in attentional brain processes, which decide what the body should pay attention to. The thalamus and midbrain also showed reductions, including a region – the periaqueductal grey – that plays a major role in suppressing pain.
“Reductions of grey matter in these key areas may demonstrate an inability of the brain to effectively inhibit pain responses,” Seminowicz said.
The observed decreases in brain grey matter were consistent across IBS patient sub-groups, such as those experiencing more diarrhea-like symptoms than constipation.
“We noticed that the structural brain changes varied between patients who characterized their symptoms primarily as pain, rather than non-painful discomfort,” said Mayer, director of the UCLA Center for Neurobiology of Stress. “In contrast, the length of time a patient has had IBS was not related to these structural brain changes.”
Mayer added that the next steps in the research will include exploring whether genes can be identified that are related to these structural brain changes. In addition, there is a need to increase the study sample size to address male-female differences and to determine if these brain changes are a cause or consequence of having IBS.
The study was funded by the National Institutes of Health.
Additional authors include M. Catherine Bushnell, Ph.D., of McGill University, and Jennifer B. Labus, Joshua A. Bueller, Kirsten Tillisch and Bruce D. Naliboff, Ph.D., all of UCLA.
Metabolic syndrome (MetS) is a condition characterised by central obesity, hypertension, and disturbed glucose and insulin metabolism. The syndrome has been linked to increased risks of both type 2 diabetes and cardiovascular diseases.
Gut microflora and metabolic syndrome
“The recent discovery by our group that patients feeding a fat-enriched diet develop diabetes and obesity through changes of their intestinal microflora has led us to envision innovative strategies aiming to hamper the development of the deleterious intestinal bacterial ecology observed during metabolic diseases,” said Professor Remy Burcelin of INSERM, who led the study.
The current study involved administering the probiotic strain B420 to diabetic mice on a high-fat diet. According to the researchers, the probiotic improved the fasting glycaemia and restored the glucose turnover rate to the level of the control mice fed with normal chow.
“Importantly, the probiotic treatment reduced the fasted insulin levels, but improved the insulin secretion upon glucose challenge, indicating an improved metabolic flexibility and restoration of normal glucose metabolism, and a potential beneficial effect on metabolic syndrome,” said Danisco.
The company added that the beneficial effect of B420 is mediated by a reduction of the pro-inflammatory molecule, plasma lipopolysaccharide (LPS). “B420 changes intestinal mucosal microbiota and reduces the efflux of LPS into plasma, thereby reducing inflammation and improving insulin metabolism,” it said.
Probiotics and obesity
A breakthrough paper published in Nature in December 2006 reported that microbial populations in the gut are different between obese and lean people, and that when the obese people lost weight their microflora reverted back to that observed in a lean person, suggesting that obesity may have a microbial component.
More findings on the topic have since trickled through the scientific web. At a scientific symposium organised by the Beneo Group in April 2008, Dr. Kieran Touhy from the University of Reading noted that obese animals have significantly lower bifidobacteria levels than their lean counterparts, which suggests potential for prebiotic fibres since the growth of these bacteria is selectively promoted by inulin and fructooligosaccharides.
Dr. Nathalie Delzenne from the Catholic University of Louvain in Belgium and Dr. Robert Welch from the University of Ulster presented results from animal and human studies, respectively, which indicated the potential of prebiotic supplementation to regulated food intake.
“This is an interesting new research area which may open up new opportunities for functional foods in the future,” said Dr Julian Stowell, head of scientific affairs for Danisco's Health and Nutrition Platform.