Microscopic colitis is a digestive condition that leads to long-term, fluctuating episodes of diarrhea. Many foods seem to trigger diarrhea in microscopic colitis patients, while other foods are easier on the gut. A low-FODMAP diet is a popular option for gut conditions like irritable bowel syndrome (IBS) and ulcerative colitis. But can it help your microscopic colitis? Let’s find out.

What is microscopic colitis?

Microscopic colitis is inflammation of the large intestine that’s only visible under a microscope. Contrast this to ulcerative colitis, where the inflammation is visible to the naked eye in the form of ulcers.

Doctors are not sure why microscopic colitis occurs — there seems to be white blood cell or collagen infiltration of the gut under a microscope. As you approach 60 years of age, your chances of developing the condition increase.

If you have microscopic colitis, you may experience:

• Long-term, non-bloody diarrhea that lasts more than a month
• Weight loss
• Abdominal pain
• Dehydration
• Fatigue
• Muscle pain 

There’s an association between microscopic colitis and a class of drugs called NSAIDs. NSAIDs are pain-killers, and examples include Advil and Aleve. If you take a lot of over-the-counter NSAIDs, your microscopic colitis may get triggered, which is why doctors recommend patients to avoid them.

Is a low-FODMAP diet good for microscopic colitis?

A low-FODMAP hasn’t been studied specifically in relation to microscopic colitis. This is why it’s difficult to say whether it’s effective in the condition. Currently, doctors don’t use (or recommend) a low-FODMAP diet to microscopic colitis patients. In fact, no dietary recommendations exist for the disease.

However, because FODMAPs are osmotic (meaning they draw in water in your gut), a diet rich in FODMAPs may make the diarrhea associated with microscopic colitis worse. When you’re experiencing a flare, talking to your doctor about a low-FODMAP diet may be useful.

How to follow a low-FODMAP diet for microscopic colitis?

Following a low-FODMAP diet for microscopic colitis involves eliminating all FODMAP-containing foods from your diet and adding them back slowly.

FODMAP is short for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols. Examples of FODMAP sugars include fructose and fructans. These sugars are fermented by bacteria in your gut, leading to the release of gas. In addition to giving you bloating, cramping, and abdominal pain, FODMAPs can trigger the symptoms of IBS.  

This is why the diet is very effective in patients with IBS. If you have microscopic colitis and IBS together, you should definitely talk to your doctor about a low-FODMAP diet. 

When you begin a low-FODMAP diet, you stop eating FODMAP-containing foods for 2-6 weeks. Here’s a list of foods you need to avoid:

• Milk
• Most fruits
• Vegetables like onions, okra, garlic, and mushrooms
• Beans
• Barley
• Wheat
• Nuts
• Sweeteners

Once all your symptoms resolve, you start adding these items back one by one. The goal is to catch specific foods that have been triggering your symptoms and avoid only those. That’s because avoiding all FODMAP foods will lead to nutritional deficiencies.

Before implementing a low-FODMAP diet for microscopic colitis, talk to your doctor. As mentioned earlier, there are no studies that support its use for microscopic colitis and your doctor will make a decision based on whether you have other coexisting gut conditions. 

It’s also important to consult a doctor because during the elimination phase, you may get malnourished. The low-FODMAP diet is very restrictive (you have to avoid most fruits and veggies), and your doctor will ensure you get adequate nutrition via alternative sources during the elimination phase.

What triggers microscopic colitis?

Although a low-FODMAP diet is not very useful in treating microscopic colitis, several foods and lifestyle activities can trigger the condition, and avoiding them is useful.

Fatty, high-fiber foods, dairy products, gluten-containing items, caffeine, sugar, inadequate hydration, spicy foods, and eating large meals can all make microscopic colitis worse. If you have the condition, consider avoiding the following items:

• Coffee
• Tea
• Chocolate
• Ice-cream
• Milk
• Cheese
• Yogurt
• Beans
• Potatoes
• Raw fruits
• Whole-grain food items
• Raw veggies

Many patients with microscopic colitis also have celiac disease. If you have microscopic colitis, your chances of developing celiac disease are higher than the average population. In celiac disease, your body is intolerant to a protein called gluten. Gluten is found in bread, pasta, breakfast cereal, and cakes.

If you develop abdominal symptoms after eating gluten-containing items, you may have celiac disease on top of microscopic colitis. The only treatment for celiac disease is lifelong avoidance of gluten.

Note that food sensitivities vary between patients. What worsens your symptoms might be completely fine for another patient and vice versa. Instead of eliminating everything in this list, keep a food diary.

In a food diary, you write everything you eat, the serving size, and the how you feel after eating a particular food. At the end of a month or two, you can analyze the diary (preferably with a doctor or a dietitian) and identify the foods that trigger your microscopic colitis. You can then avoid those items.

What to eat in microscopic colitis?

Eating a soft, easy-to-digest diet is helpful in microscopic colitis. Consider increasing the following in your diet:

• Bananas
• Rice
• Well-cooked veggies
• Probiotics — although the evidence for these is not strong, so talk to your doctor
• Water — because diarrhea in microscopic colitis can lead to dehydration
• Broth

You should avoid alcohol.

Takeaway

Microscopic colitis is inflammation of the large intestine that’s not visible to the naked eye. It leads to long-term, non-bloody diarrhea, and may lead to weight loss if severe.

A low-FODMAP diet has not been studied with regards to microscopic colitis, so we’re not sure how effective it is in the condition. However, it may ease your diarrhea during a flare-up because FODMAPs normally draw water in your gut. A low-FODMAP diet is also useful if you have IBS and microscopic colitis together.

Finally, many foods seem to make microscopic colitis worse. It’s best to avoid them. Other foods are easier on the gut, and you may want to increase them in your diet.  

If you’re still thinking about a low-FODMAP diet, make sure you consult your doctor first.

 Medically Reviewed by Onikepe Adegbola, MD PhD