An anti-inflammatory diet with olive oil, whole foods, and limited ultra-processed food may help lower inflammation associated with ulcerative colitis (UC).

Ulcerative colitis (UC) is a type of inflammatory bowel disease (IBD) characterized by chronic inflammation and ulcers, or sores, in the innermost lining of the colon and rectum.

When severe, UC can be very painful and debilitating, causing symptoms such as abdominal pain, diarrhea, and rectal bleeding.

Because UC is an inflammatory condition, many people with the disease have found relief by consuming an anti-inflammatory diet.

There isn’t a one-size-fits-all diet for UC, as it affects each person differently, and what works for one may not work for another.

However, several studies have demonstrated the benefits of lowering the intake of ultra-processed foods, added sugar, refined grains, and saturated fats for managing inflammation associated with conditions such as UC.

Mediterranean diet

There’s notable evidence that the Mediterranean diet, a popular anti-inflammatory diet, may be beneficial for UC.

In general, the Mediterranean diet includes the following characteristics:

  • being rich in plant foods (olives, fruits, vegetables, legumes, seeds, cereals)
  • high to moderate intakes of fish and seafood
  • moderate consumption of eggs, poultry, and dairy products (cheese and yogurt)
  • low consumption of red meat
  • moderate consumption of alcohol (mainly red wine with meals)
  • olive oil serving as the primary source of fat

One of the protective effects of the Mediterranean diet is the fatty acid profile (35% total fat; high in monounsaturated fatty acids and low in polyunsaturated fatty acids).

A Mediterranean diet is also rich in fruits and vegetables, and this may be helpful for UC prevention. Research from 2021 found that eating more fruits and vegetables is linked to a lower risk of IBD.

The diet may also be beneficial for children with the disease. One study found that the Mediterranean diet reduced inflammatory markers and disease symptoms in 100 children and adolescents with IBD.

Olive oil

Olive oil, the Mediterranean diet’s main source of fat, may be a major driver of the diet’s beneficial effects. Olive oil is a rich source of monounsaturated fats and antioxidants, both of which have anti-inflammatory effects on the body.

One study of 40 people with UC found that consuming extra virgin olive oil improved UC symptoms. In particular, olive oil reduced inflammatory markers and significantly reduced:

  • bloating
  • constipation
  • fecal urgency
  • incomplete defecation

Specific carbohydrate diet

Another anti-inflammatory diet often used for UC is the specific carbohydrate diet (SCD), a restrictive diet that eliminates grains, legumes, and processed foods and focuses on providing nutrients from whole, unprocessed foods (select vegetables, fruits, meats, and dairy products).

The SCD is based on the idea that certain complex carbohydrates, such as those found in grains and legumes, can contribute to inflammation and digestive problems in people with IBD.

Is fiber beneficial for UC?

The effects of fiber on UC have been mixed. Though fiber is well-known to be beneficial for gut health, some people with UC say their symptoms get worse when they eat high fiber foods.

Some evidence suggests this can be solved by increasing the consumption of anti-inflammatory foods that are higher in soluble fiber and lower in insoluble fiber.

Insoluble fiber is that which isn’t easily digested by the body. It includes foods such as whole grains, wheat bran, and the skin of fruits and vegetables.

For instance, foods that contain higher levels of soluble dietary fiber and limited insoluble fiber and may be easier for people with UC to tolerate include:

  • bananas
  • broccoli
  • nuts
  • tomatoes
  • carrots
  • mushrooms
  • peeled apples
  • citrus fruits

Fermented foods

Fermented foods, such as yogurt or kefir, are also helpful for people with UC. According to research from 2022, this is because many people with UC have a depletion of certain bacteria found in fermented dairy products known as Fusicatenibacter saccharivorans, which help support microbiome diversity in your gut.

Research suggests that anti-inflammatory diets, such as the Mediterranean diet, may be therapeutic for IBDs such as ulcerative colitis because of their ability to lower inflammation and modulate the gut microbiome.

This is important because people with IBD have an imbalance in the types of bacteria in their gut compared with those without IBD. This imbalance, called dysbiosis, is linked to inflammation in the digestive tract.

UC has increased significantly in the last few decades because of an increase in the typical Western diet, which includes excess sugar, refined carbohydrates, and high amounts of unhealthy fats.

It’s been shown that ultra-processed foods can worsen IBD. Two recent studies show that soft drink consumption is linked to a 69% increased risk, and intake of sucrose, a specific type of sugar, is related to a 10% increased risk of UC development.

Research from 2022 reported an association between intake of red meat, poultry, and processed meat and the development of UC.

Certain additives, such as carrageenan, may also exacerbate UC. One study found that a carrageenan-free diet reduced relapse in people with UC.

Carrageenan is a very common food additive used for its gelling, thickening, and stabilizing properties. Carrageenan, which is “generally recognized as safe” by the Food and Drug Administration (FDA), has been shown to cause inflammation in thousands of cell-based and animal studies.

UC symptoms vary from person to person, depending on the severity of inflammation and where it occurs.

Most individuals with UC have mild to moderate symptoms, and some have long periods of remission.

Signs and symptoms of UC may include:

  • abdominal pain and cramping
  • diarrhea, which may include blood or pus
  • rectal bleeding (passing a small amount of blood with stool)
  • rectal pain
  • inability to pass stools despite urgency
  • tenesmus (feeling like you have to pass stools even though your bowels are empty)
  • weight loss
  • fever
  • fatigue
  • failure to grow (in children)

An anti-inflammatory diet, such as the Mediterranean diet, may help lower inflammation in the digestive tract and alleviate some of the symptoms of UC, including abdominal pain, rectal bleeding, and diarrhea.

If you live with UC, it’s important to discuss any new diet with a healthcare professional or a registered dietitian before you get started.