The Surprising Science of Canned Vegetables and FODMAPs
For those on a low FODMAP diet, packaged foods can present challenges due to potential trigger ingredients. Canned vegetables offer an advantage. The FODMAPs (fermentable oligo-, di-, mono-saccharides, and polyols) in many vegetables are water-soluble. During canning, these carbohydrates can move into the brining liquid. Draining and rinsing canned vegetables can significantly lower their FODMAP content, making options that might be high-FODMAP when fresh, suitable for a low FODMAP diet.
Approved Low FODMAP Canned Vegetables
Stock your pantry with these specific canned vegetables. Remember that portion control is essential on a low FODMAP diet.
- Carrots: They have no detectable FODMAPs, making them a safe and versatile choice.
- Green Beans: These are low FODMAP, but be aware of the serving size. A standard low FODMAP serving is about 75g or 15 green beans.
- Hearts of Palm: Naturally low in FODMAPs, and a good choice for salads.
- Baby Corn: Canned baby corn is suitable in a ½ cup serving.
- Bamboo Shoots: Both raw and canned bamboo shoots are considered low FODMAP.
- Water Chestnuts: A crunchy, low FODMAP addition for stir-fries and salads.
- Canned Beets: Canned, pickled beets are low FODMAP in a ⅓ cup serving, but fresh beets are high.
- Canned Tomatoes (Drained): A ½ cup (100g) serving of canned plum tomatoes is low FODMAP, but larger amounts increase the fructan content.
- Mushrooms (Canned): While most fresh mushrooms are high in FODMAPs, a small 6-mushroom serving of canned mushrooms can be low FODMAP, due to the canning process.
- Pumpkin (Canned): Canned Japanese or Kent pumpkin are low FODMAP in a ⅓ cup serving.
The Importance of Rinsing and Draining
For any canned vegetable that is conditionally low FODMAP, it is crucial to drain and rinse it thoroughly. For example, canned green peas are only low FODMAP in a small, drained, and rinsed portion. The liquid in the can contains the leached-out FODMAPs and should be discarded. Pour the contents into a colander, rinse under running water, and make a high-FODMAP food more gut-friendly.
A Note on Additives
Always read the ingredient list when buying canned goods. Many canned vegetables are in sauces or with seasonings that contain high-FODMAP ingredients like onion or garlic powder, high fructose corn syrup, or other fructans. Choose plain canned vegetables with minimal ingredients and no added sauces.
Canned Vegetables: Low FODMAP vs. High FODMAP
To make informed choices, it helps to know which vegetables to avoid entirely in their canned form and which are generally safe. The following comparison table provides a quick reference.
| Canned Vegetable | Low FODMAP? | Safe Portion Size (Monash University App Reference) | What to Look Out For | Reason (FODMAP Category) | 
|---|---|---|---|---|
| Carrots | Yes | No FODMAPs detected | Additives, garlic or onion powder | None | 
| Green Beans | Yes (conditional) | 75g or 15 beans | High portions can contain sorbitol | Sorbitol (Polyol) | 
| Peas | Yes (conditional) | 53g (about 1/4 cup), drained and rinsed | Over 75g is high in GOS | GOS (Oligosaccharide) | 
| Mushrooms | Yes (conditional) | 6 small mushrooms (canned) | Fresh mushrooms are high in mannitol | Mannitol (Polyol) | 
| Artichoke Hearts | No | Avoid during elimination phase | High in fructans, canning doesn't remove enough | Fructans (Oligosaccharide) | 
| Sweet Corn | Yes (conditional) | 1/2 cup canned | Larger portions contain sorbitol | Sorbitol (Polyol) | 
| Asparagus | No | Avoid during elimination phase | High in fructans | Fructans (Oligosaccharide) | 
How to Safely Incorporate Canned Vegetables
Incorporating low FODMAP canned vegetables into meals is easy. Use canned carrots and green beans in soups and stews. Add drained and rinsed canned mushrooms to a low FODMAP pasta sauce made with canned plum tomatoes (in the correct serving size). For a quick side dish, sauté canned green beans with olive oil and a sprinkle of salt. Treat canned vegetables as you would fresh ones—avoiding high-FODMAP seasonings and sticking to the approved serving sizes. For a comprehensive guide on low FODMAP portion sizes, the Monash University FODMAP Diet app is an invaluable resource.
Conclusion: Making Smarter Choices with Canned Goods
A low FODMAP diet does not mean you have to give up the convenience of canned vegetables. By understanding the effects of the canning process on FODMAP content, using proper draining and rinsing, and paying close attention to ingredients, you can include a variety of canned vegetables. Keeping low FODMAP options like carrots, green beans, and water chestnuts ensures you can prepare quick, gut-friendly meals. Always listen to your body and consult with a healthcare professional or registered dietitian. For more scientific information, refer to the National Institutes of Health.