Mexican restaurants with IBS, celiac disease or food allergies

Often, yes. Mexican food is built on corn, and Monash University has tested corn tortillas and found them low FODMAP, noting you should choose tortillas made from corn rather than wheat flour. The things to ask about are beans, garlic and onion in salsas and marinades, whether corn tortillas and chips share oil or griddles with wheat, cheese and cream if lactose bothers you, and peanuts or sesame in sauces like mole if you have an allergy.

Because so many dishes are assembled from separate parts (a tortilla, a filling, rice, toppings, salsa), Mexican menus can be easier to adjust than dishes where everything is cooked together. The trick is knowing which parts to ask about.

These are starting points, not guarantees. Every kitchen is different, so you'll still need to check your own triggers or allergens.

Monash's general advice for eating out is to choose protein-based meals with vegetables, salad, potato or rice, and to ask for dips, sauces and dressings to be served separately, since they often contain garlic and onion.

For people following a low-FODMAP approach, the main things to look out for on a Mexican menu are beans and the garlic and onion that flavor many fillings and sauces.

• Beans. Monash describes beans as high FODMAP and, in its own beef tortilla recipe, swaps them out. Refried and whole beans are often served as a side, so you can usually leave them off. Our guide to beans, lentils and chickpeas explains more.
• Salsas, guacamole and other dips. Monash notes that dips and sauces are often where hidden garlic and onion are, so ask what's in them or have them on the side.
• Fillings and marinades. Ground meat, shredded chicken and slow-cooked fillings are often seasoned with garlic and onion. Ask whether a plain grilled option is available.
• Rice and soups. Ask whether the rice or soup is made with a stock that contains onion or garlic. Monash suggests being wary of stock-based dishes.
• Wheat tortillas. Flour tortillas are wheat-based, and Monash recommends choosing tortillas made from corn rather than wheat flour.

If heat is one of your triggers, it's fine to ask for a milder version; see spicy food, IBS and reflux. For the wider picture, start with hidden garlic and onion.

Corn is naturally gluten-free, but that doesn't make every corn dish celiac-safe. A University of Arizona dietitian handout suggests asking Mexican restaurants specific questions about their tortillas, because wheat can reach them in several ways.

• Tortillas. Ask whether the corn tortillas are pure corn or have wheat flour added for texture.
• Preparation. If tortillas are made on site, ask whether corn tortillas are made in a separate area from flour tortillas, and whether they're heated and served separately.
• Oil and fryers. Ask whether corn tortillas are dipped in the same oil as flour tortillas. For chips and tostadas, the Celiac Disease Foundation suggests asking whether there is a dedicated fryer or whether the oil is changed for gluten-free food.
• Marinades. The Arizona handout notes that soy sauce is often used in marinades and that some restaurants use beer, which is made with barley.
• Sauces. Ask whether sauces are thickened with flour. The Celiac Disease Foundation suggests asking if a sauce contains flour, soy sauce or teriyaki sauce.
• Rice. Ask whether the rice is cooked in a broth, and check the broth.
• Fried and coated dishes. Ask whether anything has been dusted with flour before frying.

Our guides to eating out with celiac disease and hidden gluten sources cover the wider picture. If you think you might have celiac disease but haven't been tested, talk to your doctor about testing before going gluten-free.

Cheese and cream-based toppings appear on many Mexican dishes, and they are usually easy to leave off or have on the side.

• If lactose is one of your triggers, Monash notes that harder cheeses are lower in lactose than soft cheeses, so it helps to ask what type of cheese is used.
• Ask for cheese and cream toppings on the side if you're unsure.
• A milk allergy is different from lactose intolerance. If you have a milk allergy, tell staff it's an allergy, and ask about butter, cheese and cream in sauces, rice and fillings.

See which cheeses are low in lactose and lactose-free vs dairy-free for more.

Food Allergy Research & Education (FARE) lists Mexican restaurant food among places where peanuts may be used, noting a high risk of cross-contact even if you order a peanut-free dish. The same page lists mole sauce, enchilada sauce, chili sauce, hot sauce and chili as possible sources of peanut. The AAAAI also names Mexican mole among sauces where peanut, tree nuts and sesame are common.

• Peanut, tree nuts and sesame: mole, other sauces and salsas. FARE also lists tortilla chips among foods that may contain sesame.
• Milk: cheese, sour cream and cream sauces.
• Wheat: flour tortillas, and anything fried in shared oil with them.
• Fish and shellfish: seafood tacos and ceviche; ask about shared fryers and griddles if you have a fish or shellfish allergy.

FARE recommends calling ahead between meal periods to speak with a manager or chef, and asking whether they have separate cutting boards and utensils. Read any packaged food labels every time, since ingredients change, and take "may contain" statements seriously. If you have a severe reaction, use your prescribed epinephrine and call emergency services.

1. Check the menu online and look for an allergen guide or a note about dietary requirements.
2. Call outside busy hours if you have celiac disease or an allergy, and ask about fryers, griddles and tortillas.
3. Say your most important need first. "I have celiac disease" or "I have a peanut allergy" tells the kitchen this is about safety. For IBS, name the ingredients you avoid.
4. Build your plate from parts. A protein, corn tortillas or rice, simple vegetables, and sauces on the side.
5. Leave off what you don't need. Beans, onion, cheese or cream can usually be removed without changing the rest of the dish.
6. Check the plate when it arrives, especially that tortillas are corn if that's what you ordered.

If you eat at chains, our Chipotle guide looks at one chain's own allergen information.

• "Are your corn tortillas 100% corn, or is any wheat flour added?"
• "Are the corn tortillas heated separately from the flour tortillas?"
• "Are the chips fried in a dedicated fryer, or shared with anything breaded or made with flour?"
• "Is there garlic or onion in the salsa, the marinade or the rice?"
• "Could I have the chicken grilled plain, with sauces on the side?"
• "Is the meat marinated in soy sauce or beer?"
• "I have a peanut allergy. Does the mole or any sauce contain peanuts, nuts or sesame?"
• "Could I have it without beans, cheese or sour cream?"

For more on wording, see talking to restaurant staff about allergies and eating out with IBS.