Spicy food with IBS and reflux: chili, capsaicin and hidden garlic

Not for everyone, but it is a common trigger. Chili itself is generally low in FODMAPs, yet Monash University explains that capsaicin, the compound that makes chili hot, can worsen abdominal pain and diarrhea in some people with IBS. For reflux, the 2022 American College of Gastroenterology guideline names spicy foods among those that can potentially aggravate symptoms.

Often the bigger issue isn’t the chili at all. Spice blends, curry pastes and hot sauces can carry garlic and onion, which are high in fructans. So when a spicy meal disagrees with you, it is worth asking whether it was the heat, the garlic and onion, the richness of the dish, or the portion.

Capsaicin acts on a receptor called TRPV1, which can produce pain and a hot sensation in the gut. A review by gastroenterologist Sutep Gonlachanvit in the Journal of Neurogastroenterology and Motility sums up the research this way:

• A single spicy meal can aggravate abdominal pain and a hot, stinging sensation in people with dyspepsia and IBS. In one study of people with diarrhea-predominant IBS, meals with chili caused more of these symptoms than standard meals.
• Regular chili over several weeks improved dyspepsia and reflux symptoms in a few small studies.
• The evidence is limited. The studies are small, and the author calls the idea of chili as a helpful food a hypothesis that needs more research.

In other words, the research doesn’t support a blanket rule in either direction. It supports noticing your own response, because people with the same condition can react to the same dish quite differently. Monash’s advice is simple: if spicy foods seem to trigger your symptoms, limit chili and try milder spices.

Spicy food is one of the classic reflux triggers people mention. The ACG guideline notes that in lab studies, spicy food had little to no effect on pressure in the lower esophageal sphincter, the valve that keeps stomach contents down, while still listing it among foods that can potentially aggravate symptoms. Its recommendation is to avoid the foods that are triggers for you, rather than a fixed list.

With reflux, the whole dish matters. If a spicy meal is also rich, large or eaten late, any of those could be playing a part. The ACG suggests avoiding meals within two to three hours of bedtime. See acid reflux and GERD food triggers for the full picture, and our guide to tomatoes, reflux and histamine if your spicy dishes are tomato based.

For many people with IBS, the trigger in a spicy dish is the garlic and onion, not the chili. Monash suggests avoiding seasoning mixes and blends during elimination unless you can check every ingredient.

US labeling helps a little. Under the FDA regulation 21 CFR 101.22, garlic and onion don’t count as "spice", and garlic powder and onion powder must be named on the label. But "natural flavor" isn’t broken down, and spices can be listed together simply as "spice".

Our guide to hidden garlic and onion goes deeper, including how garlic-infused oil can carry the flavor without the fructans.

Coeliac UK’s gluten-free checklist puts individual herbs and spices, ground pepper and mustard powder in its gluten-free column, and lists blended and powdered seasonings, curry powder, packet sauces and mixes under "need to check". If you have celiac disease, look for a gluten-free label on blends, and see hidden sources of gluten.

For allergies, FARE notes that allergens outside US labeling law, such as mustard, may be hidden in terms like "natural flavorings". Advisory statements like "may contain" are voluntary, and their absence doesn’t mean a product is free of your allergen. Contact the manufacturer if you are unsure. Our guide to reading food labels for allergens explains US and EU/UK rules.

You don’t have to give up flavorful food. In its guide to herbs and spices by cuisine, Monash lists many spices as low FODMAP, including cumin, coriander, turmeric, ginger, cinnamon, cardamom, fenugreek, paprika and black pepper, and includes curry powder in its Indian and Sri Lankan list. If you have celiac disease, curry powder is still one to check for gluten, as above.

Serving sizes matter for FODMAPs, and the Monash app has the current tested amounts for individual spices and chili products. Our guide to FODMAP portion sizes explains why dose matters.

• Turn the heat down, not off. Use less chili and see whether that is enough.
• Make your own blends from single spices, so you know there is no garlic, onion or wheat.
• Use garlic-infused oil, chives or the green part of spring onion for savory depth.
• Choose milder warmth from ginger, black pepper or smoked paprika.
• Order milder when eating out, and ask for sauces on the side. See Indian restaurants and Thai and Vietnamese restaurants.

Some questions that help when ordering a spicy dish:

• "Can this be made milder, or with the chili served on the side?"
• "Does the sauce or spice paste contain garlic or onion?"
• "Is the spice blend made in house, and does it contain wheat flour?"
• "I have a food allergy to ___. Can you check the sauce, the paste and the garnish?"

Staff may not know every ingredient in a ready-made paste or sauce. If they aren’t sure and you have an allergy or celiac disease, it is reasonable to choose something simpler. Our guide to talking to restaurant staff about allergies has more on how to ask.

1. Talk to your doctor or a registered dietitian ahead of cutting out foods.
2. Separate the heat from the garlic and onion: try a dish made with chili but no garlic or onion, and note how you feel.
3. Change one thing at a time: the amount of chili, the type of chili, or the time of day.
4. Record what you ate and how you felt in a food and symptom diary.
5. Keep the version that works for you, and revisit it from time to time with your dietitian.

If you have reflux as well as IBS, test the timing of spicy meals too, since a late dinner can matter as much as the heat. Get medical advice for frequent heartburn, trouble swallowing, vomiting, blood in your stool, unexplained weight change, or symptoms that wake you at night. If you are working through a low-FODMAP approach for IBS, a dietitian can help you test both chili and fructans.