Ulcerative colitis: Symptoms, diet, causes, and treatment

Ulcerative colitis is a fairly common chronic, or long-term, disease that causes inflammation of the large intestine. It is a form of inflammatory bowel disease that has some similarity to Crohn’s disease.

The colon, or large intestine, removes nutrients form undigested food and gets rid of waste products through the rectum and anus when we pass feces.

In ulcerative colitis, the colon becomes inflamed. In severe cases, ulcers form on the lining of the colon. The ulcers sometimes bleed and produce pus and mucus.

According to a study published in the American Family Physician, ulcerative colitis affects between 250,000 and 500,000 people in the United States, with an annual incidence of 2 to 7 per 100,000 persons.

The rectum is the end of the colon. It is always involved in ulcerative colitis. If the inflammation is only in the rectum, the disease is called ulcerative proctitis. However, the inflammation can extend into the upper parts of the colon. Universal colitis, or pancolitis, is when the whole colon is affected.


Ulcerative colitis
Abdominal pain is a common symptom of ulcerative colitis

The first symptom is diarrhea. The feces become progressively looser and there may be crampy abdominal pain with a severe urge to have a bowel movement.

Diarrhea may begin slowly or suddenly. Symptoms depend on how much of the colon is affected and how inflamed it is.

The most common symptoms include:

abdominal pain

bloody diarrhea with mucus

The following are also possible:

fatigue or tiredness

weight loss

loss of appetite


elevated temperature


feeling the urge to empty the bowels constantly

Symptoms are often worse early in the morning.

There may be very mild symptoms or no symptoms at all for months or years, but symptoms will return without treatment.

Signs and symptoms vary depending on which part of the bowel is affected.

Ulcerative proctitis

Inflammation is just inside the rectum. Signs and symptoms include:

rectal bleeding, which may be the only symptom

rectal pain

an inability to move the bowels, despite an urge to do so

Ulcerative proctitis is usually the mildest form of ulcerative colitis.


This involves the rectum and the sigmoid colon, which is the lower end of the colon.

Signs and symptoms include:

bloody diarrhea

abdominal cramps

abdominal pain

constant urge to use the bathroom

Left-sided colitis

Inflammation includes the rectum, up the left side through the sigmoid and descending colon.

Signs and symptoms include:

bloody diarrhea

abdominal cramping on left side

weight loss


The whole colon is affected. Signs and symptoms include:

bloody diarrhea (some bouts may be severe)

abdominal cramps

abdominal pain


considerable weight loss

Fulminant colitis

A rare form of colitis that can be life-threatening. The whole colon is affected.

Signs and symptoms include:

severe pain

severe diarrhea, which can lead to dehydration and shock

With fulminant colitis, there is a risk of colon rupture and toxic megacolon. The colon can become severely distended.


Some dietary tips may help relieve symptoms.

Tips include:

eating smaller meals, more often, for example five to six small meals a day

drinking plenty of fluid, especially water, to prevent dehydration

avoiding caffeine and alcohol, as they can increase diarrhea

avoiding sodas, as they can increase gas

keeping a food diary, and noting which foods make symptoms worse

The United Kingdom’s National Health Service (NHS) suggest that, during a flare-up, temporarily following a low-fiber diet may help. This includes refined foods, such as white rice, lean meat or fish, eggs, and cooked vegetables. This should be discussed with a healthcare professional first.

It may help to take supplements or to eliminate specific foods, but this should only be done after talking to a doctor about it.

Foods to eat and avoid with ulcerative colitisFoods to eat and avoid with ulcerative colitis
Find out more about what to eat and what not to eat
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It remains unclear exactly what causes ulcerative colitis. Genetics, the environment, and the body’s own immune system are thought to be involved.

Genetics: About one-fifth of people with ulcerative colitis have a close relative who has had the same disease, suggesting that the disease can be inherited.

Environmental: Diet, air pollution, cigarette smoke, and poor hygiene may contribute.

Immune system: One possibility is that the body’s response to a viral or bacterial infection causes the inflammation linked to ulcerative colitis. After the infection has gone, the immune system continues responding, resulting in ongoing inflammation.

Another theory is that ulcerative colitis is an autoimmune condition, in which a fault in the immune system causes it to fight non-existent infections, leading to inflammation.

High intake of linoleic acid: One study has found that one third of all cases are linked to a high intake of linoleic acid, a common fatty acid. It can be found in red meat, several cooking oils, and some types of margarine.

Risk factors

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