UC and Nutrition: What Is Your Diet Missing?

Medically Reviewed by Neha Pathak, MD on May 03, 2024
5 min read

What you eat doesn't cause or cure ulcerative colitis. But eating a diet that’s good for you is always a wise idea. It may even help you spend more time in remission and feel better.

Malnutrition isn’t usually a problem. Your small intestine is where you absorb vitamins, minerals, and proteins. And UC usually doesn’t affect that part of your body.

Still, it can be tricky to eat a well-balanced diet. Many people with UC find certain foods don't agree with them. And loss of appetite or fear of eating can cause you to lose weight or miss out on nutrients.

The best time to think about nutrition is when you're not having a flare.

Most experts say that people with UC should simply try to eat a well-balanced diet whenever possible. This should include a variety of foods:

  • Lean meat, fish, and poultry
  • Low-fat dairy products
  • Bread, cereal, and whole grains
  • Fruits and vegetables
  • Healthy fats such as vegetable oils

Keep a food diary to help you figure out which foods cause problems for you and whether or not you're getting enough nutrients.

If you lose weight because of your ulcerative colitis, try to eat five or six small meals and snacks during the day instead of two or three large meals.

When you have chronic diarrhea, drink plenty of water or other fluids to stay hydrated.

A dietitian can plan a diet that meets your calorie and nutrient needs. Before you take any dietary supplements, talk to your doctor or dietitian. Find out how to make a diet plan for ulcerative colitis.

You may not have to say goodbye to foods such as whole grains, fruits, and vegetables because you have UC. Besides its nutritional benefits, fiber soaks up extra water in your system and can firm stools.

Even if a high-fiber food seems to worsen your UC symptoms during a flare-up, it may be OK when the flare is over. The only way to know if a particular food is a problem for you is to remove it from your diet and then gradually start to eat it again.

Aim for 20 to 30 grams of fiber a day. Steaming, baking, or stewing fruits and vegetables before eating them may be easier on your digestive tract than eating them raw.

If your doctor has recommended a low-fiber diet, you may miss out on the vitamins and minerals that are naturally in many high-fiber foods. Ask your doctor or dietitian if you should take a supplement. Know how to identify foods that can trigger ulcerative colitis flares.

Fish oil -- found in salmon, mackerel, sardines, herring, and black cod, as well as supplements -- acts as an anti-inflammatory. Though early studies are mixed, fish oil and flaxseed oil may help tame colon inflammation. Learn more about the benefits of fish oil supplements.

Probiotics are "good" bacteria that live in your intestines. You can also find them in foods like yogurt and in supplements. Some researchers, as well as people with inflammatory bowel disease, think probiotics help ease symptoms.

Researchers think adding more probiotics to your digestive tract might help treat the disease. In European studies, the probiotic E. coli Nissle helped prevent UC flares, but it isn't available in the U.S. Other studies are testing different probiotics to help control UC. If you and your doctor decide to try probiotics, you'll need to keep taking enough of the right kind for it to work. Get more information on how probiotics can help ease symptoms of ulcerative colitis.

People with UC often think they have lactose intolerance, which means they can't properly digest the sugar in milk and milk products, because some symptoms are similar. But UC doesn’t make you more likely to have lactose intolerance. Your doctor can do a simple test to find out.

If you can, keep milk and dairy products in your diet. They are a very good source of calcium and vitamin D, which keep your bones healthy. Using steroids such as prednisone for a long time can thin your bones and make it harder for your body to absorb calcium, raising your chance of having osteoporosis.

If dairy products cause you discomfort, see if you can eat them in small amounts. Or try a lactase supplement to break down the lactose in dairy products.

If you just can't stomach dairy products, your doctor may want you to take calcium and vitamin D supplements. Watch a video on how dairy affects ulcerative colitis.

It may be best to avoid more fibrous foods like whole grains, greens, and nuts when you’re having a flare up. Instead, look for easy-to-digest foods like:

  • White bread (instead of whole grain)
  • Refined breakfast cereals like cornflakes (instead of oats, bran, or granola)
  • White rice instead of harder-to-digest brown or wild rice
  • Low-fiber fruits like bananas, cantaloupe, honeydew melon, and cooked fruits
  • Fully cooked non-cruciferous vegetables like asparagus tips, potatoes, squash without the peel, seeds, or stalks
  • Refined, low-fiber pasta and noodles
  • Lean meat and fish
  • Eggs

For some people with UC, it also helps to break meals up into five or six smaller meals instead of three larger ones. You can talk to your health care team about going on an elimination diet. That’s when you stop eating different foods one at a time to see which ones tend to cause symptoms so you can remove them from your diet. It’s important to work with your doctor or dietitian when you do this to make sure you get enough nutrients.

If you find that you are losing weight during a flare up, talk to your health care team. They might need to test to see if you’re getting enough of certain vitamins and minerals. They also may be able to help you zero in on foods that worsen your symptoms and help you replace them with healthy alternatives that will help you maintain a healthy weight. These might include some of the foods above, like bananas, eggs, lean meat, and noodles.

If you still have trouble finding foods that agree with you or you continue to lose weight, talk to your doctor about possible liquid nutritional supplements. 

People with UC need to be especially careful to get enough folate, iron, and potassium.

Folate helps prevent cancer and birth defects. Some medications such as sulfasalazine (Azulfidine) can make it harder for your body to absorb folate.

Blood loss due to inflammation and ulcers in the colon can cause low iron levels. A simple blood test can tell.

Diarrhea or taking steroids can cause low potassium and magnesium levels.

Talk to your doctor about whether these nutrients could be a problem for you. You may need to take vitamins just in case. Nutrition supplement drinks can also make up for missing nutrients, but they may cause diarrhea. Find out more on vitamins and supplements for ulcerative colitis.