Researchers evidence that many athletes may have undiagnosed irritable bowel syndrome


Exercise can have significant effects on gastrointestinal diseases.

Regular, moderate exercise can impart beneficial effects for the intestinal microbiome, irritable bowel syndrome symptoms, and inflammatory bowel disease.

High-intensity training or prolonged endurance training, on the other hand, can have negative effects on these same entities.

Female athletes report a higher prevalence of irritable bowel syndrome and celiac disease, and furthermore, have gastrointestinal symptoms modulated by the menstrual cycle.

Management of gastrointestinal problems in the athletic population is widespread and includes training adjustments, dietary measures, and medicine management of symptoms.

A recent study by researchers at the University of Illinois suggests that many of these athletes may have undiagnosed irritable bowel syndrome.

About half of the 430 endurance athletes surveyed reported some symptoms of irritable bowel syndrome, with some athletes having symptoms severe enough to disrupt their training and competition schedules.

U. of I. alumna and then-doctoral student Lauren A. Killian conducted the survey to determine just how prevalent IBS might be in this population.

Through national athletic clubs and social media, Killian recruited athletes who had completed or planned to participate in marathons, ultramarathons or half- or full-distance triathlons.

Participants were asked about gastrointestinal symptoms such as cramps and pain, bloating, diarrhea or constipation, which can be indicative of IBS.

Athletes were asked if they had experienced these symptoms when they were at rest, during training or competition, and within two hours of physical activity.

More than half of the athletes in the study reported some gastrointestinal difficulties, but the data indicated that the overall prevalence of IBS among them was similar to that of the general population in the U.S. at about 10 percent, Killian said.

While less than 3 percent of the study participants had been diagnosed with IBS by a clinician, another 7 percent of them met the Rome III diagnostic criteria for IBS – the clinical standards that many physicians were using to diagnose the disease when the surveys were administered, between December 2015 and January 2017.

Irritable bowel syndrome (IBS) is a functional bowel disorder characterized by chronic or recurrent symptoms of abdominal pain that is associated with altered bowel function (i.e., pain related to defecation, changes in stool frequency, or appear-ance) .

Additional symptoms of IBS may include straining, fecal urgency, and bloating.

IBS can further be subdivided by stool consistency, namely, constipation-predominant IBS (IBS-C), diarrhea-predominant IBS (IBS-D), or mixed bowel habit pattern (IBS-M).

Importantly, patients with IBS report reduced health-related quality of life (HRQOL) compared with individuals with-out IBS .

As many as 48 million individuals in the United States are thought to be affected by IBS annually, yet up to 75% of patients with IBS may lack a formal medical diagnosis of IBS.

Although diagnostic symptom criteria exist for IBS ( 1,3 ), the IBS (IBS-C), diarrhea-predominant IBS (IBS-D), or mixed bowel habit pattern (IBS-M).

Importantly, patients with IBS report reduced health-related quality of life (HRQOL) compared with individuals with-out IBS.

As many as 48 million individuals in the United States are thought to be a ected by IBS annually, yet up to 75% of patients with IBS may lack a formal medical diagnosis of IBS.

Although diagnostic symptom criteria exist for IBS, they are mainly used in clinical research studies, rather than used routinely in clinical practice.

In a US study using a large health insurance database, patients with IBS were most likely to receive a diagno-sis from an internist (68%) rather than a gastroenterologist (13%) .

Hungin et al. conducted a European study that surveyed 3,880 participants with IBS symptoms and suggested that primary care physicians may have an even greater role in IBS diagnosis and management; the authors found that most patients with medically diagnosed IBS sought medical care from primary care physicians (90%) rather than gastroenterologists (28%).

Of symptomatic indi-viduals lacking a medical diagnosis of IBS, Hungin et al, found, for a European population, that 37% did not receive care, whereas 55 and 12% sought medical care from primary care physicians and gastroenterologists, respectively.

A comparable, but smaller, US community survey study conducted by the same group found similar results.

The reasons for the lack of a formal diagnosis of IBS for many individuals are not entirely clear, but likely are multi-factorial. Individuals with IBS symptoms often describe a range of gastrointestinal (GI) symptoms, including reflux-like symptoms, dyspepsia, and IBS-related symptoms (e.g., fecal urgency, bloating).

IBS-D may pose a relatively greater diagnostic challenge than the other bowel habit subtypes, as celiac disease and inflammatory bowel disease, among other conditions, need to be considered in patients with chronic or recurrent diarrhea.

In fact, current evidence suggests that celiac serologies and inflammatory markers such as C-reactive protein and fecal calprotectin should be obtained in these patients .

Previous studies have compared GI and psychologic symptoms between individuals with IBS symptoms who seek healthcare and those who do not; however, differences between individuals with diagnosed and undiagnosed IBS (including those who had visited a physician for their IBS-related symptoms) have not been well studied.

The European and US surveys performed by Hungin et al. were conducted >10 years ago, used older diagnostic criteria for IBS and bowel habit subtypes, and did not focus on patients with IBS-D.

Thus, the objective of this investigation was to compare symp-tom characteristics, healthcare utilization, HRQOL, treatments, and perceived explanations for GI symptoms in patients diagnosed with IBS-D using contemporary criteria compared with individu-als who remain undiagnosed despite having sought medical atten-tion for IBS-related symptoms.

To be diagnosed with IBS under the Rome III criteria, patients must experience abdominal pain or discomfort at least three days per month for three months, along with two or more other symptoms.

However, when Killian applied an older diagnostic tool called the Manning criteria, which includes a broader array of gastrointestinal symptoms, the proportion of the athletes with possible IBS jumped to nearly 23 percent.

“If you’re suffering with these types of symptoms consistently, don’t assume it’s something you have to live with just because you’re very active,” said U. of I. food science professor Soo-Yeun Lee, who co-wrote the study. “You may have IBS and want to seek medical advice.”

For elite athletes, the inability to compete means lost income and possibly a derailed career, Lee said.

IBS symptoms were nearly three times as common among women, who also were significantly more likely to report that their bowel problems interfered with training or competition, the researchers found.

Athletes with gastrointestinal problems may benefit from dietary changes, medications and other strategies that can mitigate the pain and help them manage their symptoms, Killian said.

Although athletes often consume significant amounts of carbohydrates to boost their performance prior to a race, being more selective about the types of carbohydrates they consume can dramatically improve IBS symptoms, she said.

Clinicians often advise people with IBS to restrict their intake of short-chain carbohydrates, which ferment in the gut, causing digestive problems such as bloating, gas and stomach pain.

Lee said these symptoms can be significantly reduced by following a low-FODMAP diet.

FODMAP is an acronym that refers to fermentable oligo-, di- and mono-saccharides and polyols, groups of short-chain carbohydrate molecules that are poorly absorbed in the small intestine.

Foods that contain high amounts of these types of carbohydrates include wheat, garlic, onions and fruits with significant levels of fructose or glucose such as apples, cherries and peaches.

Some vegetables such as asparagus and cauliflower also contain high levels of short-chain carbohydrates, as do legumes, chickpeas and lentils.

Likewise, some dairy products and beverages, including alcohol and chai or chamomile teas, can be problematic too.

Killian said athletes with gastrointestinal issues may want to experiment with reducing their intake of these foods and beverages to see if their condition improves.

“Knowing their individual reaction to these foods can help people tailor their diets to their body’s needs,” Killian said.

More information: Lauren A. Killian et al. Irritable Bowel Syndrome is Underdiagnosed and Ineffectively Managed Among Endurance Athletes, Applied Physiology, Nutrition, and Metabolism (2019). DOI: 10.1139/apnm-2019-0261

Journal information: Applied Physiology, Nutrition, and Metabolism
Provided by University of Illinois at Urbana-Champaign


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