The Core Difference: Protein vs. Carbohydrates
Gluten-free and low FODMAP diets are often confused, but they address different dietary components. Gluten is a protein found in wheat, barley, and rye, requiring strict avoidance for individuals with Celiac disease. FODMAPs, however, are fermentable carbohydrates that cause symptoms in people with IBS. While there's overlap because grains like wheat and rye are avoided in both, a food's gluten-free status doesn't indicate its FODMAP content. The low FODMAP diet is a temporary process, while the gluten-free diet for Celiac disease is lifelong.
Naturally Gluten-Free Foods That Are High in FODMAPs
Many naturally gluten-free foods are high in FODMAPs, and should be limited during the low FODMAP elimination phase. This includes certain fruits (apples, pears, mango), sweeteners like honey and agave, larger portions of some legumes and nuts (cashews, pistachios), and vegetables such as garlic and onions. Additionally, some gluten-free flours (chickpea, coconut) and additives like inulin can be high in FODMAPs.
Navigating a Combined Gluten-Free and Low FODMAP Diet
Managing both diets simultaneously requires careful label reading and planning. Prioritize checking ingredient lists for high FODMAPs in gluten-free products. Look for certifications from Monash University or Fodmap Friendly on packaged goods. Cooking at home allows for better control over ingredients, and techniques like using garlic-infused oil can add flavor without fructans.
Combining Gluten-Free and Low FODMAP: A Comparison
| Food Category | Standard (High FODMAP/Gluten) | Gluten-Free (Can be High FODMAP) | Gluten-Free and Low FODMAP Options |
|---|---|---|---|
| Grains | Wheat bread, Rye pasta | Gluten-free bread with high FODMAP flours, plain GF oats (check portion) | Rice, Quinoa, Oats (certified GF), Buckwheat, Cornmeal |
| Flours | Wheat, Rye, Barley | Chickpea flour, Coconut flour, Soy flour | Rice flour, Corn flour, Oat flour, Sorghum flour |
| Sweeteners | High Fructose Corn Syrup, Honey, Agave Syrup | Any of the aforementioned high FODMAP sweeteners | Maple syrup, Table sugar, Stevia (some types) |
| Protein Sources | Marinated meats, sausages, some legumes | Cashews, Pistachios, Soybeans, some dried legumes | Eggs, Plain meats/fish, Firm tofu, Tempeh |
| Sauces/Condiments | Store-bought sauces with onion/garlic | Packaged GF sauces containing onion/garlic/concentrates | Garlic-infused oil, Plain mayonnaise, Soy sauce (limited amounts) |
The Role of a Dietitian
Given the complexity, consulting a registered dietitian is highly recommended. They can help ensure nutritional needs are met, especially for vital micronutrients, and guide the FODMAP reintroduction process. A dietitian can also help differentiate Celiac and IBS symptoms.
Conclusion
In summary, being gluten-free does not mean a food is low FODMAP. While both diets exclude high-FODMAP, gluten-containing grains, gluten-free certification doesn't guarantee the absence of fermentable carbohydrates. Managing both conditions effectively involves paying close attention to ingredients and portion sizes, often with professional dietary guidance. A diverse and enjoyable diet that is both gluten-free and low FODMAP is achievable with the right knowledge.
How to get started on your combined diet
If you have Celiac disease and persistent IBS-like symptoms, your doctor might suggest a low FODMAP diet trial. Start with a strict gluten-free diet, then undertake the 3-phase low FODMAP process, beginning with a 2-6 week elimination phase. Symptom relief during this phase often indicates FODMAPs as triggers. Reintroduce each FODMAP group systematically to find your personal tolerance levels for a more flexible diet. The Monash University FODMAP app can be a useful tool.
