Feeling confused about how canned champignon (button) mushrooms can be low FODMAP? That’s not surprising, as button mushrooms are well known for being high FODMAP! The good news is that manufacturing processes, like canning, can have a huge impact on the FODMAP content of food. Both the type of food and the liquid it is stored in can influence the overall FODMAP level of canned foods.
How does canning the food decrease the FODMAP content?
FODMAPs are water-soluble carbohydrates. This means when a high FODMAP food is stored in water or brine the FODMAPs can leach out of the food and into the liquid, lowering the overall FODMAP level (1).. However, it can be hard to predict if enough of the FODMAP content will leach out of the food to reduce the FODMAPs from high to low levels (2). This means to get accurate data on FODMAPs the canned food needs to be tested by a FODMAP trained laboratory.
What high FODMAP foods become safe to eat when canned?
Canned Champignon (Button) Mushrooms in Brine
Fresh button mushrooms are high FODMAP for mannitol in ½ cup servings and contain both high levels of mannitol and moderate levels of fructans in 1 cup servings. Canned champignon mushrooms are popular in Asian cuisine, and they are low FODMAP in ½ cup serves1. This is most likely because the mannitol & fructans in the champignon mushrooms leach into the brine, lowering the overall FODMAP content of the mushrooms themselves. Just remember to buy champignon mushrooms in brine (NOT sauce) and rinse them well before using them.
Canned Lentils
Boiled lentils contain moderate amounts of FODMAPs (some of the FODMAP content leaches into the water as you boil them), however, canned lentils are lower in FODMAPs and can be enjoyed in 1/4 cup serving sizes1. This is because the water-soluble GOS (oligosaccharides) and fructans leach out of the lentils into the water content1. Always rinse canned lentils well before using!
Canned Chickpeas (Garbanzo beans)
Dried chickpeas are considered high FODMAP, however, their canned counterparts are much lower in FODMAPs. Again the GOS in the chickpeas leaches out into the water and lowers the chickpea FODMAP level, making a ¼ cup serve of canned chickpeas low FODMAP (1). However, always remember to rinse them before using them.
Canned Baby Corn
Baby corn is an immature ear of corn that is picked before it has a chance to mature. Canned baby corn is low FODMAP in 1 cup serves. However, be careful to avoid canned sweet corn kernels as these are high FODMAP even in small serves (1).
Does canning reduce the FODMAP content of all legumes/beans?
Unfortunately, while canning reduces the FODMAP content of some legumes/ beans, it doesn’t make all of them low FODMAP. Canned baked beans, borlotti beans, four bean mix, butter beans, and black beans are still high FODMAP, although some may have a smaller serving size that only contains low to moderate levels of FODMAPs (1). Check the Monash Low FODMAP App for more information.
What about canned fruit?
Monash University is yet to test a wide range of canned fruit. We do know that canned guava is low FODMAP in 27g serves (1).
If you want to consume canned fruit, then my team of registered dietitians would recommend that you test your tolerance to low FODMAP fruit that is canned in syrup not fruit juice. Fruit juice can contain excess fructose and polyols, which can increase the overall FODMAP level of the product. Instead, buy canned fruit in syrup. Look for ones that contain water and sugar, and avoid any syrups that contain high fructose corn syrup or high FODMAP sweeteners. Then rinse your fruit well using a sieve before consuming, to remove any additional FODMAPs in the liquid.
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Be Aware of Canned Tomato…
Just before you throw two cans of plain crushed tomatoes into your spaghetti bolognese… be aware that canned tomatoes appear to have higher levels of FODMAPs compared to fresh tomatoes. According to the Monash App a ½ cup (92g) serve of canned tomato is low FODMAP, however, contains moderate FODMAPs at a 115g serve, and becomes high FODMAP at a 1 cup (180g) serve (1). This means you need to split a 400g can of tomatoes between four serves. You can make your tomato sauce go further by adding low FODMAP chicken stock, a little bit of tomato paste, and some cornflour (starch) to thicken.
Watch Out For Sneaky FODMAPs
Avoid canned food that has added high FODMAP ingredients like onion, garlic, or high fructose corn syrup, as these will increase the FODMAP content of the food.
Final Thoughts
Canning high FODMAP foods can reduce their FODMAP content, however, it is hard to predict if enough FODMAPs will leach into the water to make the food low FODMAP. This means you should check the Monash low FODMAP app to see if your canned food is low FODMAP before consuming.
Rich says
June 12, 2019 at 8:39 amThanks for the great article! However, just having a look at the Monash App it looks like that most forms of tomato are now allowed, except for sun-dried which need to be eaten in moderation.
Alana Scott says
June 12, 2019 at 9:01 amHi Rich,
Thanks for the comment! Monash is still in the process of updating the traffic light information in the Monash University FODMAP app so you need to check for additional notes by clicking into each food. When you click into ‘tomato, canned’ in the app you will see a note that says larger serves of 115g contain moderate amounts of FODMAPs, and past data in the app indicated that 180g serves were considered high FODMAP.
A lot of recipes using canned tomatoes use well over 115g of tomato per serve which is why we include a warning note in this article. We hope this helps!
Nick says
June 25, 2019 at 11:34 pmI’m confused on olives. Most green olives that are pitted have pimentos, red peppers, or some other kind of vegetable. I’ve never seen if a pimento is Low FODMAP. Also, some of the ingredients in the water are not low FODMAP compliant. Can you wash the olives off so they could be compliant? Thank you! Nick
Alana Scott says
June 26, 2019 at 5:59 amHi Nick
Thanks for commenting. Okay so Monash FODMAP has tested pitted green olives and pitted black olives and both are low FODMAP. So far red pepper and red chili have come back with low FODMAP serves. This means if your symptoms are settled you could test your tolerance to green olives stuffed with pimento – if the brine contains onion or garlic powder make sure you rinse them well before eating.
I hope that helps!