Tag: gastrointestinal

Categories : Diet and Nutrition GastrointestinalTags :

Underweight and Gastrointestinal Distress – A Bidirectional Relationship?

On By ModernMedia

An Asian cross-sectional study found that underweight was linked to functional dyspepsia (FD), regardless of the presence of anxiety, although anxiety was additionally associated with FD.

The study by Kee Huat Chuah, MD, of the University of Malaysia in Kuala Lumpur, and colleagues, also found no link between high body mass index (BMI) and other functional gastrointestinal disorders (FGIDs). People with FGIDs often have irritable bowel syndrome, functional dyspepsia, or functional constipation. These conditions affect up to 40% of people at any one point in time, two-thirds will have chronic, fluctuating symptoms. The questionnaire-based study recruited 1002 adult individuals with a median age of 32, with 20.7% having FGID according to the Rome III criteria.

Across different FGIDs, including irritable bowel syndrome (IBS) and functional diarrhea and constipation, FD affected more underweight adults (defined as BMI less than 18.5) compared with a non-FGID control group (13.3% vs 3.5%, P=0.002). Multivariate analysis showed that underweight maintained an independent association with FD, at an odds ratio (OR) of 3.648 (95% CI 1.494-8.905, P=0.004).

The results of a large population study from France were consistent with these findings, which also found that being underweight was independently associated with FD in females.  Diarrhoea may also have been associated with central obesity, but there were too few individuals with diarrhoea to draw conclusions, although a large US population study from 2019 showed that obesity was associated with chronic diarrhoea.

A bidirectional association has been observed in eating disorders (often linked with anxiety disorders) with both a low BMI and FD.  Anxiety and/or eating disorders may have caused FD subjects to have a low BMI.

William D Chey, MD, of Michigan Medicine, who was not involved with the research, said the results were interesting and that they could be applicable to the US population since obesity rates are comparable to those in Malaysia.

“But I do agree it’s important to consider whether these observations are cause or effect,” Chey commented. “In other words, FD might cause people to lose weight or thin people might be more prone to developing FD. I do think there’s face validity to these observations. Remember that patients with functional dyspepsia that have meal-related symptoms of fullness and early satiety are unable to eat very much without feeling ill.”

Patients with postprandial distress syndrome often lose weight as a result, Chey continued. “On the other hand, patients with anorexia often have measurable abnormalities in gastric emptying, but that’s not to say all FD patients have eating disorders. My point is that certain non-GI conditions associated with weight loss can also be associated with abnormal GI function.”

The team called for further studies of longitudinal design to explore whether anxiety causes a low BMI in FD or vice versa. Limitations included not being population based, with the cohort being mostly hospital and university staff members. In addition, the data on psychological disorders came from a subgroup of original participants in the study’s second phase; the number of participants with functional diarrhoea was low; the cross-sectional design did not allow for causality; and the questionnaire only asked about dietary habits.

Source: MedPage Today

Journal information: Beh KH, et al “The association of body mass index with functional dyspepsia is independent of psychological morbidity: a cross-sectional study” PloS One 2021; doi: 10.1371/journal.pone.0245511.

Categories : Allergies GastrointestinalTags :

Stomach Bugs Induce Irritable Bowel Syndrome

On By ModernMedia

Researchers have pinpointed a localised biological mechanism behind irritable bowel syndrome (IBS), a chronic gastrointestinal condition where eating certain foods causes subsequent abdominal pain or discomfort.

Around 20% of people experience IBS, and diets such as gluten-free ones provide some relief. However, the exact cause was unknown, as the patients did not have allergic responses nor did they have coeliac disease, causing many physicians to dismiss it as psychological.A healthy immune system tolerates foods, and the first link is understanding how the tolerance is removed. Previous work showed that there was a link between mast cells and food, and that blocking histamine in people with IBS relieved the symptoms.

People with IBS often report their symptoms begin following a gastrointestinal infection, so the researchers reasoned that an infection associated with a particular type of food in the guy might sensitise the immune system to that food.The team fed mice with ovalbumin (an egg protein) and then infected them with a stomach bug. The mice were then fed ovalbumin again, and the researchers recorded elevated mast cell activation, histamine levels and digestive intolerance. In control mice who were fed with ovalbumin but who were not infected with the stomach bug, there was no response.

Breaking down the chain of events leading to the sensitisation, the researchers discovered that there was a localised immune response in the part of the guy infected by the bacteria, but did not produce the more generalised symptoms of a food allergy.  

Lead author Prof Guy Boeckxstaens, a gastroenterologist at KU Leuven thinks this may point to a spectrum of food-related immune disorders. He said, “At one end of the spectrum, the immune response to a food antigen is very local, as in IBS. At the other end of the spectrum is food allergy, comprising a generalised condition of severe mast cell activation, with an impact on breathing, blood pressure, and so on.”

When researchers injected IBS-associated food antigens into the intestinal walls of IBS patients, they observed localised reactions similar to what they saw in the mice, and there were no reactions in healthy patients. Larger clinical trials will be needed to confirm these observations.

“This is further proof that the mechanism we have unraveled has clinical relevance,”  Prof Guy Boeckxstaens said. “But knowing the mechanism that leads to mast cell activation is crucial, and will lead to novel therapies for these patients,” he goes on. “Mast cells release many more compounds and mediators than just histamine, so if you can block the activation of these cells, I believe you will have a much more efficient therapy.”

Source: Medical Xpress

Journal information: Local immune response to food antigens drives meal-induced abdominal pain, Nature (2021). DOI: 10.1038/s41586-020-03118-2 , www.nature.com/articles/s41586-020-03118-2

Categories : Gastrointestinal Neurodegenerative DiseasesTags :

Gut Immune Cells Protect The Brain in MS Flare-ups

On By ModernMedia

Scientists from the University of California, San Francisco, have observed gut immune cells moving up out of the gastrointestinal tract to the brain during multiple sclerosis (MS) flareups, where they seem to exert some protective effects.

In MS, other immune cells attack the myelin sheath, resulting in flare-ups, where they experience memory problems, vision loss, pain and other problems. These flare-ups subside after some days, but it is not known why the disease switches back and forth between flare-up and remission.

The new research revealed that the flare-ups were brought under control with the unlikely assistance of gut immune cells, which produce Immunoglobulin-A (IgA) and act as the immune system’s first line of defence in the GI tract. Some of these cells actually leave the gut and migrate to the brain, where it appears they reduce inflammation.

“It was a very new idea,” said lead author, Sergio Baranzini, PhD, neurology professor at the UCSF Weill Institute for Neurosciences, . “Nobody thought to look for this type of immune cell.”

The gut immune cells were found only in cerebrospinal fluid of MS sufferers when they experienced a flare-up, and not in remission. Recent research indicated that an unhealthy GI microbiome was involved in MS, and the researchers determined that these immune cells only attacked potentially damaging bacteria, not the myelin sheath.

It is anticipated that this discovery may bring insights into new therapies to treat the disease. 

Source: Medical Xpress