Each diet is simple enough on its own. Together, they take away exactly what the other one leaned on: the vegetarian loses seitan, wholemeal pasta and a good share of meat substitutes; the celiac loses the meat and fish that were the easy source of iron. It isn’t impossible, plenty of people do it well, but this is a plate you build, not one you get by avoiding things.

What leaves the menu, and why

  • Seitan, the classic vegetarian answer to texture, is pure gluten. Out, no discussion.
  • Textured wheat protein, the base of many veggie burgers, nuggets and mince. Out.
  • Processed meat substitutes: some are soya or pea based and gluten-free, some contain wheat flour or wheat gluten as a binder. No rule here: every product has to be read, and the scanner finds wheat even when it is hidden.
  • Wholemeal bread, wholemeal pasta, bulgur, couscous, spelt, which were bringing fibre and protein to the vegetarian plate.
  • Nutritional and brewer’s yeast flakes, common in vegan cooking for the flavour and the B vitamins, to be bought labelled gluten-free.
  • Soy sauce, barley miso, marinated tempeh: often wheat or barley.

What stays, and it is a lot

Protein. Legumes are the backbone: lentils, chickpeas, beans, split peas, broad beans, labelled gluten-free where you can find them. Soya in all its forms: tofu, plain tempeh (check the marinade), edamame, soya milk and yoghurt. Quinoa, amaranth and buckwheat, pseudo-cereals that carry a complete protein. Seeds (pumpkin, sunflower, hemp, chia, sesame) and nuts. Pea or rice protein powders, labelled. And for vegetarians, eggs and dairy, which settle a good part of the question.

Starches. Brown rice, potatoes, sweet potato, corn, polenta, buckwheat, millet, legume pastas (lentil, chickpea) that are both a starch and a protein, and cost very little.

Dishes from around the world that never needed wheat or meat: Indian dhal, chilli sin carne, potato tortilla, chickpea curry, quinoa buddha bowls, buckwheat galettes, hummus and falafel (bound with chickpea, not flour), stir-fried rice with tofu and certified tamari.

The deficiencies to watch closely

This is where the two diets stack up, because celiac disease already absorbs poorly what a plant-based diet supplies less easily.

  • Iron. Plant iron is less well absorbed than iron from meat, and a celiac gut absorbs it badly, it is the most common symptom. Legumes, tofu, quinoa, pumpkin seeds, spinach, with vitamin C at the same meal and tea kept well away from it. Ferritin test at the start, supplement if needed.
  • Vitamin B12. Absent from plant foods. If you are vegan it is always supplemented, celiac or not; if you are vegetarian, eggs and dairy provide some, but celiac absorption can be reduced. Get it measured at the start.
  • Calcium and vitamin D. Without dairy, calcium comes from fortified plant drinks, calcium-set tofu, green vegetables, almonds, sesame, calcium-rich mineral waters; vitamin D is nearly always supplemented. Celiac bone needs it.
  • Zinc, iodine, omega-3: seeds, seaweed, rapeseed and flaxseed oil, or supplements, depending on your blood work.
  • Protein, finally, if the plate narrows: it is not a problem when legumes and soya are there every day, it becomes one when dinner turns into “vegetables and rice”.

The real risk: the plate that shrinks

It has to be said, because dietitians see it: two restrictive diets stacked on top of each other can drift towards eating that is far too narrow, out of weariness, out of fear, or out of perfectionism. Fatigue, weight loss, missed periods, obsessing over labels: these are warning signs. Someone who is both celiac and vegan needs a more carefully built plate than average, not an emptier one, and a dietitian, at least at the start, to put together meals that cover everything. That is the most useful piece of advice in this article.

Eating out

Combining the two makes going out harder, but less than you would think: the cuisines that suit one usually suit the other. Indian food (dhal, vegetables, rice; watch out for naan and pakora), Mexican with corn tortillas (beans, guacamole), Thai and Vietnamese built on rice (with certified tamari in your bag), poke and bowls, and fully gluten-free venues, almost all of which have vegetarian dishes. The Nutrixe map flags dedicated kitchens; the vegetarian question comes afterwards, and it is usually the easier of the two.

In short

  • Seitan, wheat protein, a good share of meat substitutes and wholegrain cereals are out: every product has to be read.
  • Legumes, soya, quinoa, buckwheat, seeds, nuts, plus eggs and dairy for vegetarians: the protein is there.
  • Iron, B12, calcium, vitamin D: blood work at the start, supplements based on the results; B12 always if you are vegan.
  • The real risk is the plate that shrinks: build it, don’t only avoid, and do it with a dietitian.
  • When eating out, the cuisines that suit both diets are often the same ones.

This information does not replace medical advice. Combining a gluten-free diet with a vegetarian or vegan one should be built with a dietitian and backed by blood tests, especially for children, teenagers, and during pregnancy.