Microscopic Colitis (MC) is a type of inflammatory bowel disease, it is a chronic inflammation of the large intestine; the lining in particular, which can only be observed under a microscope. As a chronic condition, MC can come and go, being worsened by certain triggers; usually specific foods, so diet has a very big role in microscopic colitis. Microscopic colitis mainly causes watery diarrhoea that can occur several times per day. This comes and goes, in line with the inflammation and can occur along with other symptoms of gastrointestinal distress, such as stomach cramps, bloating and others.

Diet is important in the management of microscopic colitis as there are certain foods that can trigger episodes. These can be different for each person who suffers from MC, but there are certain foods that are more common than others such as airy, gluten, sugar, caffeine and alcohol. These can be removed from the diet, to lessen the chance of microscopic colitis flaring up. Diets that can be useful in managing microscopic colitis are low fat and fibre, an elimination diet or an anti-inflammatory diet. Whilst there is no definite way to ‘cure’ yourself of microscopic colitis, closely managing your diet (identifying and eliminating triggers) can reduce the chance and frequency with which episodes may occur.

Understanding microscopic colitis

Microscopic Colitis (MC) is a form of inflammatory bowel disease, specifically chronic inflammation of the lining of the large intestine. It is referred to as ‘microscopic’ colitis as this inflammation is only visible under a microscope when a biopsy of the large intestine lining has been taken.

There are two types of Microscopic Colitis, these are:

• Lymphocytic Colitis - there are more white blood cells (lymphocytes) present in the lining of the large intestine than usual
• Collagenous Colitis - The inner lining of the large intestine has a thicker layer of collagen (protein important in structure)

These changes in the gut mean that the large intestine cannot absorb as much liquid as it normally would; from the food waste that has made its way to this part of the gastrointestinal tract. This results in the watery poo (diarrhoea) that is typical of MC.¹ 

Symptoms of microscopic colitis

The most common symptom of Microscopic Colitis is chronic diarrhoea (watery poo) that occurs frequently. There are other secondary symptoms that can be common, these are: 

• Fatigue
• Gluten sensitivity
• Abdominal pain
• Bloating
• Trouble holding in poop

Other more severe symptoms include : 

• Dehydration
• Nausea and vomiting
• Weight Loss

These are not a definite group of symptoms that would be suffered by someone with MC, all are possible and symptoms may come and go alongside the inflammation of the intestinal lining.² 

Diagnosis

To diagnose microscopic colitis, your doctor would ask about the symptoms being suffered, medical history and current medications, They would then order a battery of tests; blood, stool and imaging, to rule out any other disorders that have a similar presentation as MC, such as coeliac disease or other inflammatory bowel diseases. If there is nothing out of the ordinary with the tests more must be done to confirm MC.

To confirm a diagnosis of MC a doctor would perform a colonoscopy during which they would take a biopsy (removal of some tissue) of the lining of the large intestine. Microscopic colitis can then be confirmed by viewing the biopsy under a microscope, where the inflammation will be visible.³

Causes and treatment

Upon diagnosis of MC, your doctor would go over any medications you are currently taking, with the hope of identifying whether any are causing the condition and whether changing current medications could help manage MC. Medications that can trigger MC are:

• Non-steroidal anti-inflammatory Drugs (NSAIDs) such as ibuprofen
• Proton pump inhibitors (lansoprazole), reduce stomach acid levels
• Selective serotonin reuptake inhibitors, used to treat depression
• Hormone replacement therapy (HRT)
• Beta Blockers
• Statins

Other causes may include damage to the gut lining caused by bacteria, genetic factors and lifestyle factors (smoking, diet)⁴ 

There is no cure for Microscopic Colitis, as it is a chronic condition, and the treatment focuses on managing and limiting symptoms. The main medications used to combat symptoms of MC are:

• Antidiarrheals - Loperamide is mainly used to reduce the amount of liquid in excrement, by slowing muscle contractions in the gut and allowing food to move slower through the intestines
• Corticosteroids - Budesonide reduces the inflammation in the large intestine
• Bile acid sequestrants - Binds to bile acids in the stomach if you suffer from bile acid malabsorption, improves symptoms of diarrhoea²

Surgery can be an option if there are no positive results after the use of medical intervention, however, this is rarely used as a treatment for MC. The surgery involves the removal of some length of the intestine.

Lifestyle changes can be key in avoiding triggers of MC, these would be to quit smoking, reduce alcohol consumption and reduce caffeine intake, as all of these can be common triggers.

Dietary management of microscopic colitis

There is no set diet that can guarantee a reduction in the symptoms of MC, and the foods that may trigger it are different for everyone. There are however certain common triggers these are: 

• Alcohol
• Caffeine
• Gluten
• Dairy
• Sugar

Removing or reducing these in your diet can help manage the symptoms. You can identify which foods, in particular, are your triggers by eliminating all, then gradually adding back each food, one at a time, a dietitian can aid in doing this in a safe and systematic way to ensure results.

Specific diets can be recommended for those attempting to manage MC, such as : 

• Low fat-low fibre diet - this gives the gastrointestinal system less work to do and can be recommended by healthcare providers
• Anti-inflammatory diet - polyunsaturated have been seen to reduce inflammation, a Mediterranean diet is an example²

The best diet for managing MC is different for each person; as their triggers may be different so finding and avoiding these triggers is vital.

Newer research suggests that a diet high in calcium may be beneficial and protective for those who suffer from MC. However, this may pose an issue, with dairy (a good source of calcium) can often be a trigger for those with Microscopic Colitis.⁵ 

Summary

Microscopic Colitis (MC) is a form of inflammatory bowel disease that is characterised by chronic inflammation of the large intestines lining. The main symptom is diarrhoea (watery poo), there can be other secondary symptoms that cause gastrointestinal distress (stomach ache, bloating etc.). MC can only be diagnosed through a biopsy of the large intestine’s lining that is then viewed under a microscope, revealing inflammation and confirming the diagnosis.

There is no cure for MC, but the symptoms can be managed with medication in extreme cases where medication has no effect, surgery can occur to remove some large intestines, this is however rare.

The greatest way to manage MC is through dietary control. Each person has different triggers that cause the inflammation to flare up. Once a person understands what their triggers are, they can avoid these foods in the hope of avoiding episodes of inflammation.