The dietary management of ulcerative colitis

the dietary management of ulcerative colitis

Ulcerative colitis (UC) is an inflammatory bowel disease that causes an imbalance of the colonic mucosa and a relapse function of the colon. In proctitis, which is around 50% of the ulcerative colitis cases, the affected area is just the rectum. In left-sided colitis (30% of cases), the inflammation extends to part of the colon. In 20% of the cases, the entire colon is affected, which is called pancolitis. UC is a lifelong disability that has no cure yet, and the cause of the disease is also unknown. The life expectancy of patients with UC isn’t reduced because of the illness, although life quality is severely influenced. The inflammation can come in periods, which means there are flare-ups and remissions.

Regarding the remission period, it can last from weeks even to years, when the patient is entirely symptom-free and does not have any pain. Patients are most likely to develop the illness from age 15 to 30. According to the latest findings, men are just as likely to become ill as women. Thus, there is no significant difference between the two genders.

The causes of ulcerative colitis are today unknown to the scientific community, but some speculations can play a role. A combination of genetics, environmental factors, and an overly active immune system could trigger this illness.  The most potent factor seems to be the presence of an overactive immune system. In this case, the patient’s immune cells turn against the large intestines’ inner lining, causing severe inflammation. Why precisely the excessive immune response is triggered is unknown. Environmental factors include antibiotics, NSAIDs (anti-inflammatory drugs), oral contraceptives, or a high-fat diet can increase the risk of developing UC.

Regarding genetics, it is not clear which gene makes it more likely to generate the disease, but there are correlations between the genetic factors and the illness. In approximately 20% of the cases, the patient with ulcerative colitis has a close family member suffering from the disease. Physical and emotional stress and certain types of food could trigger the disease, but they do not cause it exclusively.

Signs and symptoms of ulcerative colitis

signs and symptoms of ulcerative colitis

The symptoms of UC are varying from episodic or chronic diarrhea, abdominal cramps, constant stomach ache or discomfort, tenesmus, which is a continual or recurring inclination to abandon the bowels, a sense of wanting to go to the bathroom all the time, even when the bowels are empty.  In many cases, diarrhea can present with blood or mucus. The frequent and consequential symptoms include severe weight loss, anorexia, fever, and malaise.

There aren’t any signs of predicting the disease. Once the patients start developing symptoms, a thorough examination is needed. Initial symptoms may include fevers, abdominal pain, diarrhea, tachycardia, and a distended abdomen. The extra-intestinal signs include clubbing, oral aphthous ulcers, erythema nodosum, pyoderma gangrenosum, conjunctivitis, episcleritis, sizeable joint arthritis, ankylosing spondylitis, cholangiocarcinoma, iritis, nutritional deficit, or amyloidosis.

Tests to diagnose Ulcerative Colitis

test to diagnose ulcerative colitis

Multiple tests can diagnose ulcerative colitis, including a broad span blood test checking the following factors: FBC, ESR, CRP, U&E, LFT, blood culture. Stool samples must be taken and analyzed to exclude other bacterial infections caused by Campylobacter, Salmonella, Shigella, C. difficile, E. coli, or amoebae. In most cases, colonoscopy allows the doctor to take a biopsy and show the severity of the disease. It also helps look for inflammatory infiltrate, goblet cell depletion, glandular distortion, mucosal ulcers, and crypt abscesses.



Different drug therapies can manage symptoms. Maybe one of the obvious choices that the doctors can start treating the patient with is steroid drugs, for example, sulfasalazine, mesalazine, or prednisolone. These medications, however, can present with severe side effects, such as joint pain caused by the swelling and fluid retention, fat deposits on the neck, face, and abdomen, fatigue, and high blood pressure. It can cause psychological problems, including delirium, memory loss, or constant mood changes that can lead to severe depression. In the most severe cases, hydrocortisone can help.


Immunomodulators can also help when the steroids have failed or when prolonged therapy is required. They can support the immune functions by modifying the immune response to a stimulus. They create a more beneficial way to respond to threats by training the immune system. There is a wide variety of immunomodulators: azathioprine, methotrexate, infliximab, adalimumab, or calcineurin inhibitors such as ciclosporins)

Biological therapy

Biological therapy has achieved a form of revolution with regards to UC. The therapeutic biological agents target specific mediators in the biochemical process of inflammation. Infliximab, adalimumab, and golimumab have been approved in recent years as a treatment, and it can help bring the patients in remission or keep them in that state. These medications are all TNF-alpha antagonists, which means they stop the inflammation at the very beginning of the process. The severity of the disease does not matter; biological therapy can help in moderate or severely developed situations. There are many studies still undergoing to develop more effective drugs, and the feedback report of biological therapy treatments is very promising so far. It can help induce years of remission, and the side effects are nearly as severe as they are for steroids.

Initially, the doctor injects the medication into the abdomen or the thigh muscle, but later the patient can self-administer the therapy. For general improvement, it is necessary to take the medication every two weeks. The first milestone is after eight weeks. If the patient’s situation hasn’t improved by then, then maybe the dose needs to be adjusted. If there is no progress, then the patient isn’t susceptible to the drug and needs to stop taking it, which can happen in a few cases.


Approximately 20% of the cases need surgery to remove the inflamed part of the colon and rectum’s lining. After most types of operations, patients can still have their bowel movements, but in some less common cases, the patient needs to wear an ostomy bag that removes the stool from the body.

CBD products

In the last five years, CBD products have received increasing attention due to their potency in reducing inflammation. For this reason, it is considerable to use it for alleviating the symptoms of UC or any inflammatory bowel disease (IBD). Cannabidiol or CBD is one of the active ingredients of cannabis. It has no psychoactive effect, but it can relieve stress, reduce inflammation and pain, and strengthen the immune system. According to the most recent studies, the effects of CBD is uncertain in UC patient, and there’s no evidence that it can put people in remission. However, there is no doubt that it is useful for chronic abdominal pain and reducing inflammation. It can also help with lack of appetite, reducing blood in stool, fatigue, weight loss, and reducing diarrhea. CBD is mostly advertised more like a dietary supplement than medication, which is essential to point out. Combining CBD with a specific diet can reduce the symptoms, and people with UC generally report improvement in their state of health after trying it.   

Dietary management of ulcerative colitis

Dietary management of ulcerative colitis

Finding the right diet for ulcerative colitis is challenging. My previous article on Chron’s Disease’s dietary management describes a dietetic approach that has many similarities to other inflammatory bowel diseases, including UC. I recommend you read that article and have a full picture of inflammatory bowel diseases’ dietary management. In this post, we will dig into some specificities of UC.

Usually, it’s a good idea to start with an elimination diet, which means the patient is eating only a reduced variety of food and incrementally adds types of food to the diet.  The elimination process starts with cutting down or altogether leaving behind certain food types that make the symptoms worse. Diet doesn’t cure or change the disease’s outcome; it only helps to manage the problem and keep the symptoms at bay. This way, the patients’ quality of life can improve, and they can be in a generally better health condition. One type of diet can work for one patient while it can fail to bring benefits to another. Therefore choosing the right diet is always going to be a trial and error process.

Low residue diet plan

From a dietary perspective, residue means everything human digestion cannot process; hence it ends up in the stool. Foods that are low in fiber are recommended because they are easier to digest. They are capable of slowing down bowel movements; hence diarrhea is limited to some extent. A low residue diet is naturally low in fiber and, despite it being called a low fiber diet, the two are not precisely the same. In a low residue diet, the variety of consumed food is wider; one can eat milk products such as yogurt or cottage cheese and milk, peanut butter, fruit juices but without pulp, and meats are thoroughly cooked, for example, chicken, pork, or fish. One can also eat pasta, white bread, or cereals if they contain less than 0.5 grams of fiber per serving. Fruits and vegetables are also a good idea, especially ripe and raw bananas, watermelon, peaches and apricots, lettuces, spinach, squash, carrots, and onions.

Specific carbohydrate diet

There is much interest in the specific carbohydrate diet (SCD) role for the treatment of intestinal bowel disease (IBD). This diet should change the fecal microbiome from a pro‐inflammatory to a non‐inflammatory state by excluding foods high in complex carbohydrates. This diet excludes most starchy carbohydrates (potatoes, corn, gluten, and rice) and food additives and preservatives while allowing certain fruits and vegetables, nuts, homemade fermented yogurt, meats, eggs, butter, and oils. Improved clinical and biochemical parameters have been shown in pediatric IBD patients. A proportion of IBD patients following this diet were able to discontinue immunosuppressive agents.

Foods Allowed on the SCD

  • Meats without additives, poultry, fish shellfish, and eggs
  • Certain legumes, including dried navy beans, lentils, peas, split peas, unroasted cashews and peanuts in a shell, all-natural peanut butter, and lima beans
  • Dairy limited to cheeses such as cheddar, aged Parmesan, Colby, Emmentaler, dry curd cottage cheese; and homemade yogurt fermented for at least 24 hours
  • Most fresh, frozen, raw, or cooked vegetables and string beans
  • Fresh, raw or cooked, frozen or dried fruits with no added sugar
  • Most nuts and nut flours
  • Most oils, teas, coffee, mustard, cider or white vinegar, and juices with no additives or sugars
  • Honey as a sweetener

Foods that are not allowed on the SCD

  • Sugar, molasses, maple syrup, agave syrup, sucrose, processed fructose including high-fructose corn syrup or any processed sugar
  • All grain including corn, wheat, wheat germ, barley, oats, rice, and others. The latter includes bread, pasta, and baked goods made with grain-based flour
  • Canned vegetables with added ingredients
  • Legumes not included in the list above
  • Seaweed and seaweed byproducts.
  • Starchy tubers such as potatoes, sweet potatoes, and turnips
  • Canned and most processed meats
  • Canola oil and commercial mayonnaise (because of the additives)
  • All milk and milk products high in lactose, such as mild cheddar, commercial yogurt, cream, and sour cream, and ice cream.
  • Candy, chocolate, and products that contain FOS (fructo-oligosaccharides)

Low FODMAP diet

FODMAP stands for Fermentable Oligo-Di-Monosaccharides and Polyols. It is based on the idea that poorly absorbed carbs and sugar can lead to an overflow of gut bacteria, which causes inflammation. Therefore, the medium that the bacteria use as a source of food needs to be changed, implying that the patient’s diet must be low in fermentable oligo-di-monosaccharides and polyols since the bacteria can use as a source of food to grow. A low FODMAP diet cannot reduce inflammation, but it can reduce bloating and gas and alleviate discomfort. A dietitian can help to determine which sugars one can consume on this diet and what to avoid. In general, those who choose this diet can eat many bananas, celeries, corn, eggplant, lettuce, rice, oats, hard, cheese, honey, milk products, chicken, pork, and fish. Patients on this diet should stay away from apples (high in oligo-fructo-saccharides), cherries, pears, Brussels sprouts, wheat, rye, sweeteners high-fructose corn syrup.

General recommendations for ulcerative colitis

inflammatory bowel disease
Doctor Giving Advice On Healthy Diet

Some foods and drinks can increase inflammation in the bowels. As a rule of thumb, the following types of food must be reduced or avoided with ulcerative colitis:

  • Alcohol
  • Products high in caffeine, such as coffee, energy drinks, sodas, cocoa
  • Carbonated drinks
  • Foods that contain sulfur or sulfate (food additive)
  • Foods rich in sugar
  • Dairy products high in lactose (besides lactose-free dairy products in general, aged cheese tend to have a lower lactose concentration naturally)
  • Processed meat (canned meat, cured meat, etc.)
  • Spicy sauces

It is beneficial to write a food journal while trying out new diets. Different things can work for different people, and finding the right diet for ulcerative colitis patients is not a one-size-fits-all solution. Keeping a log about what you eat can help the doctors and dietary consultants figure out the best diet for the patient and expose which type of food one needs to avoid because they most likely trigger the inflammation and cause the flare-ups.

Future perspectives connected to fecal microbiota transplantation

fecal microbiota transplantation

Studies from the last couple of years suggest that the intestines’ microbiome plays a significant role in the pathogenesis of UC. The species of the microflora of the patients differ substantially from healthy subjects’ microflora. The unhealthy subjects generally show low levels of Firmicutes and Bacteroidetes and an increased level of Lactobacillus. The members of Desulfovibrio and Clostridium seems to be linked to the illness. The question is whether it is a cause or an effect.

Fecal microbiota transplantation is another possible way to treat the disease, and it could help bring patients into remissive states. The demand to develop a cure for ulcerative colitis increases and the research on fecal transplantation is rising. Other therapies, such as hormone therapy, biological therapy, and surgery, can have low efficacy compared to the possible outcomes of the fecal transplant. The transplantation’s main idea is to remove the gut bacteria from the patients and reintroduce a healthy intestinal flora.

During the transplantation, the healthy flora will colonize the intestines’ mucosal cells, which will increase its function of barrier. The gut bacteria works as a chemical barrier against the digested food. This process controls the intestines’ immunity; therefore, a healthy microbiome can lead to a healthy, not over-active immune response and reduced inflammation. One of the disadvantages of the therapy is that after the transplantation, the patient will be more susceptible to intestinal infections because the gut’s homeostasis is disturbed.

Gianluca Tognon

Gianluca Tognon

Gianluca Tognon is an Italian nutrition coach, speaker, entrepreneur and associate professor at the University of Gothenburg. He started his career as a biologist and spent 15 years working both in Italy and then in Sweden. He has been involved in several EU research projects and has extensively worked and published on the association between diet, longevity and cardiovascular risk across the lifespan, also studying potential interactions between diet and genes. His work about the Mediterranean diet in Sweden has been cited by many newspapers worldwide including the Washington Post and The Telegraph among others. As a speaker, he has been invited by Harvard University and the Italian multi-national food company Barilla.

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About Me

I’m an Italian nutrition coach, speaker, entrepreneur and associate professor at the University of Gothenburg. I started MY career as a biologist and spent 15 years working both in Italy and then in Sweden.

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