Ulcerative colitis (UC) symptoms such as diarrhea and reduced appetite may increase the risk of malnutrition. Working with a UC-focused registered dietitian can help people ensure that they get the nutrients they need.

UC is a form of inflammatory bowel disease (IBD) that causes inflammation and ulcers in the inner lining of the large intestine, or colon. People with UC can experience a variety of digestive issues, such as bloody diarrhea, weight loss, and decreased appetite. These effects can lead to other complications, including problems related to nutrition and health.

Malnutrition is a common problem in people with IBD and affects up to 62% of people with UC. Malnutrition is a deficiency or imbalance in the intake of energy or nutrients the body needs to carry out its everyday functions. It can result from a variety of factors and may have important implications for gut health and overall well-being.

Here, experts discuss the link between UC and nutritional health, including steps people can take to help prevent malnutrition and its associated complications.

Several factors can cause malnutrition in UC. Many of these factors work simultaneously to impair gut health and nutritional status.

“Active inflammation in the colon can lead to malabsorption of nutrients, loss of protein in the stool, and loss of vitamins and minerals,” said Christopher Steevens, MD, a Minnesota-based gastroenterologist. “Meanwhile, the nutritional needs of a person’s body increase when inflammation is present.”

“Patients may avoid certain foods they associate with increased symptoms of abdominal pain, diarrhea, etc., or they may avoid eating altogether,” he added.

“Certain medications people with UC may be on can decrease absorption of certain nutrients, leading to deficiencies as well,” said Brittany Rogers, MS, RDN, CPT, an IBD registered dietitian.

Collectively, these factors can affect how well the body absorbs nutrients from the food people eat, contributing to vitamin deficiencies, energy deficits, and a host of nutrition-related complications.

“The people most at risk of developing malnutrition are individuals with the highest symptom and disease burden,” Steevens explained. “Inflammation of the colon is the driving factor, so we would expect individuals such as those with severe pancolitis (involving the entire colon), those who are hospitalized, and those requiring advanced types of medical therapy or surgery to be the most likely to have malnutrition.”

Rogers noted that other potential risk factors for malnutrition may include:

  • missing or avoiding meals due to decreased appetite or a desire to avoid symptoms
  • avoiding multiple foods or food groups
  • experiencing nausea or vomiting

“The main sign or symptom of malnutrition that patients and caregivers are likely to notice is sudden unintentional weight loss or having a very low weight for an individual’s height,” said Steevens. “Sudden weight gain in a patient with uncontrolled UC can also be another sign of malnutrition.”

Other symptoms that people may notice include:

  • significant hair loss or a change in hair texture
  • loss of muscle mass or decreased muscle strength
  • visible changes in the appearance of the face or body
  • delayed wound healing
  • bruising
  • swelling of the legs, ankles, or feet
  • fatigue
  • frequent illnesses or prolonged recovery periods
  • depression or anxiety

“There are two easy questions that people can ask themselves to self-screen for malnutrition: ‘Have I lost weight recently without trying?’ and ‘Has my food intake decreased due to a decreased appetite?’” Rogers said. “If they answer yes to either question, they’re at risk for malnutrition and would benefit from seeing an IBD-focused registered dietitian.”

A note on weight loss

Weight loss and the commentary that often accompanies it can be challenging for many people and can lead to complicated feelings about body image and self-confidence.

“Remind yourself that it’s never appropriate for others to be commenting on our bodies and that this weight loss is not healthy,” Rogers emphasized. “If you lose weight without trying, you may have active UC, and if your body doesn’t have enough calories to maintain its weight, it doesn’t have enough calories to devote to wound healing.”

“It’s really important that you provide your body with enough nutrients to correct malnutrition,” she continued. “If you’re experiencing decreased body confidence, work with a dietitian and a therapist experienced with helping individuals improve their body image.”

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Malnutrition in UC often involves deficiencies of a variety of micronutrients, including:

  • vitamins such as vitamins A, B6, B12, D, E, and K
  • minerals such as iron, calcium, and magnesium
  • trace elements such as selenium, zinc, and manganese

Deficiencies of these compounds can affect the body’s ability to carry out its functions and may lead to health problems such as:

  • anemia or low blood counts
  • increased risk of bone fracture
  • impaired wound healing
  • blood clots
  • worsening inflammation

Malnutrition can also reduce the effectiveness of treatment for UC.

“When protein loss and malnutrition occur, many of our best therapies, such as biologic medications, do not work as well because they rely on protein in the blood to be transported,” said Steevens. “The medication can be lost in the stool if there is ongoing protein loss, rendering these infusions or injections ineffective.”

“Likewise, if a person requires surgery for their disease, malnutrition can make it much more difficult to have a successful surgery and be able to recover,” he added.

Rogers also noted that malnutrition has been linked to a variety of healthcare-related complications in UC and IBD, including hospitalization, increased healthcare costs, and death.

“The best thing people can do is to make sure they are really engaged with their gastroenterology team,” said Steevens.

This includes regular monitoring for signs of malnutrition, such as changes in appetite, unexplained weight loss, or changes in nutrient lab results. A gastroenterologist can also help people with UC get into remission to help reduce the likelihood of complications from the condition.

“I also encourage all of my patients with UC to meet with a registered dietitian who has a special interest in helping people who have IBD,” Steevens said.

Dietary recommendations to avoid malnutrition will be personalized based on an individual’s needs and symptoms but may include:

  • eating a varied diet rich in fruits and vegetables
  • avoiding highly processed foods and sugary beverages
  • refraining from keto-style diets

“For the individuals losing weight due to fear of eating pro-inflammatory foods, I tell them that there’s nothing you could eat that would be more pro-inflammatory for your body than being malnourished,” Rogers said. “So don’t worry as much about what you eat and more about eating more right now.”

People with UC and malnutrition should have close monitoring from their UC care team and nutritional team to make sure they are getting the care they need.

“I aggressively monitor the status of the UC and make medication adjustments to make sure they are working toward getting into remission,” said Steevens. “More frequent lab testing is sometimes needed to keep track of vitamin, nutrient, and inflammation marker levels.”

In severe cases, hospitalization may be necessary to help a person regain safe electrolyte and nutrient levels and prevent serious complications.

As a dietary specialist, Rogers recommends a variety of steps to help increase nutrient and calorie intake, including:

  • aiming for three balanced meals per day plus three snacks
  • drinking oral nutrition supplements or protein drinks on top of or between regular meals
  • adding healthy fats — such as avocados, olive oil, nut or seed butter, or tahini-based sauces — to meals
  • eating homemade baked goods

An IBD-focused registered dietitian or gastroenterologist can provide additional support and more tailored recommendations as needed.

“Malnutrition in people with UC is very common and is often underrecognized,” said Steevens. “People with UC should ask their providers about malnutrition and ask to work with an IBD dietitian for advice on management and preventing malnutrition. Good nutrition is increasingly being recognized as a crucial aspect in achieving the best outcomes and quality of life for patients with UC.”