Field Notes

Common GI Disorder Linked to Bacterial Overgrowth, Food Poisoning

Cedars-Sinai researchers have reported two advances in the understanding of irritable bowel syndrome (IBS), the most common gastrointestinal (GI) disorder in the United States, affecting an estimated 30 million people.

One study provided further evidence that IBS is linked to an overgrowth of bacteria in the gut. In a separate study, a mathematical model revealed the disease’s link to food poisoning and shows that military personnel are at much higher risk of the disorder than the rest of the population. The findings were reported at Digestive Disease Week.

“The better we understand this disease, which affects millions of Americans, the more tools we will have for fighting it,” said Mark Pimentel, MD, director of the Cedars-Sinai GI Motility Program and a primary investigator on the studies. “Patients with this condition suffer serious quality-of-life issues. It’s a disease that is frequently misunderstood and difficult for people to talk about, but it’s important for the medical community to understand the causes of the disease so we can develop the most effective treatments possible.”

In collaboration with researchers at Sismanogleion General Hospital in Athens, Greece, and the University of Athens, scientists looked at small-bowel cultures to confirm the presence of small intestinal bacterial overgrowth in patients with IBS. Previous studies have indicated that bacteria have a role in the disease, including breath tests finding methane (a by-product of bacterial fermentation in the gut), as well as the disease responding to antibiotics.

In this study, 320 patients underwent an endoscopy of the upper GI tract, from which a small-bowel culture was cultivated. Of those patients with IBS, 37.5% were positive for bacterial overgrowth in the small intestine compared with fewer than 10% of those who did not have the disorder. The overgrowth was more prevalent in those with the diarrhea-predominant version of the disease. Researchers also found more varieties of bacteria in IBS patients.

In a separate study using a mathematical model, researchers concluded that food poisoning (gastroenteritis) may account for the majority of IBS cases. Further, it predicted a greater incidence of the disease for populations at higher risk of these kinds of infections, such as military personnel. The study was based on data from the Centers for Disease Control and Prevention and other research studies. The model projects that 9% of those with a genetic predisposition would contract IBS after 10 years. However, among high-risk groups such as deployed military, 9% of that population would develop the disease within six months.

“While everyone understands that our troops encounter great danger and difficult conditions while serving their country, this study reminds us that we need to pay greater attention to the dietary woes and digestive upsets that long have been the subject of wry discussion among overseas forces,” Pimentel said.

— Source: Cedars-Sinai Medical Center

 

Vitamin D Improves Exercise Outcomes in Patients With COPD

Vitamin D supplements may help patients with chronic obstructive pulmonary disease (COPD) get more from their pulmonary rehabilitation programs, according to a study conducted by researchers from Belgium.

“Our study shows that high doses of vitamin D supplementation on top of a standard rehabilitation program improve the outcome in terms of exercise capacity and respiratory muscle strength,” said Miek Hornikx, a physiotherapist and doctoral student in the department of pneumology at the Katholieke Universiteit Leuven in Belgium.

Vitamin D deficiency is common among patients with COPD and is often associated with a lack of exposure to sunlight and diet. COPD patients often have limited physical activity as a result of breathing difficulties associated with the disease, which may result in less exposure to sunlight, Hornikx explained.

“COPD can be considered as a respiratory disease with important nonrespiratory consequences, such as osteoporosis, cardiovascular disease, and muscle weakness,” she said. “These consequences eventually will be negatively influenced by physical inactivity which, along with exercise intolerance, is a common feature among patients with COPD and is proven to be related to mortality.

“Low levels of vitamin D in the blood have been related with muscle weakness, a major target for respiratory rehabilitation and increased risk of falls,” she added. “Since vitamin D is often depleted in patients with COPD, we wanted to see if vitamin D supplementation would have a beneficial effect on rehabilitation among these patients, perhaps by increasing muscle strength.”

The researchers enrolled 50 COPD patients with a history of exacerbations who had been referred for rehabilitation and randomly assigned them to receive either a monthly dose of vitamin D or a placebo. Patients in the vitamin D group were given 100,000 IUs of vitamin D in their monthly dose; the U.S. recommended daily allowance of vitamin D is 600 IUs daily for adults up to age 70 and 800 IUs daily for adults older than 70.

All patients participated in a pulmonary rehabilitation program for three months. At the beginning of the study and again at the completion of the rehabilitation program, peripheral and respiratory muscle strength, exercise capacity, and vitamin D levels were measured. Patients were also asked to complete a quality-of-life survey both before and after rehabilitation.

At the end of the study, researchers found that patients treated with vitamin D had a significant improvement in exercise capacity and respiratory muscle strength compared with those in the placebo group.

“These results support the idea that correcting vitamin D deficiency by adding vitamin D supplements to training programs allows COPD patients to achieve better results from rehabilitation, including improvements in muscle strength and exercise capacity,” Hornikx said.

Interestingly, despite significant improvements in exercise capacity in patients treated with vitamin D, those patients did not report a significant increase in health-related quality of life.

“This could be due to the fact that we had a relatively small number of patients included in this study, as well as to the relatively brief duration of the study,” Hornikx said. Future studies should focus on the specific mechanisms by which vitamin D affects patients with COPD, she added.

— Source: American Thoracic Society