Coeliac disease or IBS: how do you tell?

Two different conditions

Coeliac disease is an autoimmune condition. The NHS explains that your immune system attacks your own tissues when you eat gluten, damaging the small intestine so your body can’t properly take in nutrients.

IBS is a disorder of gut-brain interaction. The NIH says it causes repeated tummy pain and bowel changes without visible damage to the gut.

They’re very different, but the symptoms can look alike.

Where the symptoms overlap

The NHS lists coeliac gut symptoms as:

• diarrhea, which may smell particularly unpleasant
• stomach aches
• bloating and farting
• indigestion
• constipation

Coeliac disease can also cause tiredness, unintentional weight loss, an itchy rash and other general symptoms.

The NHS IBS list includes stomach pain or cramps, bloating, diarrhea and constipation. See the overlap?

Why testing comes first

The NHS diagnosis page says you should be tested for coeliac disease if you have, among other things:

• persistent unexplained gut symptoms like diarrhea, stomach ache and bloating
• prolonged tiredness
• unintentional weight loss
• unexplained iron, B12 or folate deficiency anemia
• IBS (in adults)
• a parent, sibling or child with coeliac disease

The NIH also says doctors ask about a family history of coeliac disease when assessing IBS.

The gluten rule

This is the bit people miss. The NHS says: while you’re being tested for coeliac disease, you need to keep eating foods containing gluten, so the tests are accurate. You also shouldn’t start a gluten-free diet until a specialist confirms the diagnosis, even if a blood test is positive.

Testing starts with a blood test for antibodies. If it’s positive, you’re referred to a gastroenterologist, who may arrange a biopsy of the small intestine.

So if you’re thinking of cutting gluten to “see what happens”, talk to your GP about testing first.

Where gluten hides

The NHS says gluten is found in wheat, barley and rye, so it’s in:

• pasta, cakes and breakfast cereals
• most types of bread
• certain sauces and some ready meals
• most beers (made with barley)

Keeping a useful log while you wait

Since you’ll be eating gluten until you’re tested, your log can capture what happens:

Mon 13:00  Lunch (photo): ham sandwich, crisps  tags: gluten
Mon 17:00  Poop: type 6
Tue 13:00  Lunch (photo): pasta salad  tags: gluten
Tue 16:30  Poop: type 6
Wed 13:00  Lunch (photo): rice bowl
Wed  (no poop logged)

PoopAI has a gluten trigger tag, so tagged meals and Bristol types sit side by side in your weekly report. Tiredness or stomach ache are notes to keep yourself.

When to see a GP

See a GP if you have symptoms of coeliac disease or IBS, or if gut symptoms have lasted more than 4 weeks (NHS IBS page). Get urgent help for bleeding from your bottom, bloody diarrhea or a lot of weight loss for no reason.

Questions to ask yourself

Before your appointment, a few answers help your GP a lot. How long have symptoms been going on? Do they seem worse after bread, pasta or other wheat foods? Has anyone in your family been diagnosed with coeliac disease? Have you lost weight, felt unusually tired or had mouth ulcers? Have you already cut back on gluten? That last one matters, because testing needs gluten in your diet. Log your meals and poops for a couple of weeks while eating as normal, then bring the record with you. It turns a vague worry into something your GP can work with.

Wrap-up

Coeliac disease and IBS can look alike, but they’re handled very differently. Get tested before you change your diet. Keep eating gluten until your doctor says otherwise, and keep a simple log in the meantime.