Crohn's disease, a rare and incurable disease that is increasing in Korea, and ulcerative colitis, which is not rare but incurable, are grouped as inflammatory bowel diseases (IBDs).

Since IBDs cause various symptoms, including frequent diarrhea, abdominal pain, and bloody stools, people often assume that patients are underweight, but this is not true, a specialist says.

“About 15-40 percent of people with IBDs are obese, and 20-40 percent are overweight,” said Professor Park Sang-hyoung of the Department of Gastroenterology at Asan Medical Center (AMC) on the YouTube channel with the same name as the hospital. “Underweight people account for only 0.5 percent of ulcerative colitis patients and less than 3 percent of those with Crohn's disease.”

That means many IBD patients are overweight or obese. But does being overweight or obese affect inflammatory growth diseases? Yes. Obesity can affect IBDs because it activates cytokines that cause inflammation, according to the AMC specialist.

“Reports say that obesity increases the risk of Crohn's disease but not ulcerative colitis,” Professor Park said, “Other studies show that controlling obesity reduces the risk of IBDs.”

He reiterated that weight control is essential for IBD patients.

There's another reason why weight management is so important for people with IBDs: They are also at higher risk for fatty liver, a metabolic disease deeply linked to obesity, which can worsen the course of the IBD.

“Regardless of their weight and whether or not they have dyslipidemia, diabetes, or hypertension, they (IBD patients) are known to have a higher risk of fatty liver. Having these conditions can worsen the course of the disease,” Park said.

There's yet another reason why weight management is vital for people with IBDs: They are also at increased risk for obesity-related type 2 diabetes.

“IBDs are known to increase the risk of type 2 diabetes. We don't know the exact cause of IBDs, but they reportedly are caused by gut bacterial abnormalities,” Park said. “Type 2 diabetes is also known to be caused by gut bacterial abnormalities, so there is some commonality between the two diseases.”

Moreover, IBD patients with diabetes have a more difficult time managing their disease. “Compared to patients without diabetes, they have higher levels of inflammation, lower albumin, higher rates of hospitalization, and higher rates of antibiotic use,” the AMC physician said.

Patients with IBDs need to manage their disease by maintaining a healthy weight through lifestyle management. One of the dietary habits that IBD patients should avoid is an “overindulgence of simple carbohydrates.”

“Excessive intake of simple carbohydrates causes inflammation in the gut,” Park said. “Epidemiological studies have shown that it is associated with the development of IBDs, especially when fast food consumption increases and diets become more westernized.”

It's also recommended that IBD patients remain physically active.

“Studies that have analyzed the association between physical activity and inflammatory growth disorders have shown that people with Crohn's disease who were physically active had significantly lower disease severity than those who were not,” Park said.

In addition, preserving muscle mass, which is lost with age, through regular exercise is also very helpful in managing inflammatory growth disorders. “In Crohn's disease patients with sarcopenia, we found an increased risk of bowel resection and a significantly increased incidence of surgical complications,” Professor Park said.

“The response rate to drugs, including anti-tumor necrosis factor that is the primary treatment for inflammatory growth disorders, is lower in patients with sarcopenia,” Park said. “Therefore, it is necessary to prevent sarcopenia, or muscle atrophy in IBD patients.”

However, the gastroenterology specialist does not necessarily recommend vigorous exercise for IBD patients. Instead, mild exercise, such as walking, is recommended for those with the disease.

“High-intensity exercise can reduce blood flow to the digestive system, and prolonged exercise can lead to hypovolemia due to dehydration, so light exercise is recommended rather than high-intensity exercise,” he said.

Even so, doing a lot of light exercise, such as walking, is not always recommended for patients with inflammatory growth disorders.

“The amount of exercise can vary depending on the individual, but it is generally recommended to walk at least 7,000 steps a day until you are slightly out of breath,” Professor Park said. “Because there are individual differences, some people may need more than 7,000 steps, and some may only need 4,000 steps, so adjusting it according to the individual's condition is very important.”