If you’re following a low FODMAP diet due to IBS, the high FODMAP content in most mushrooms can pose a challenge. This blog explores the fascinating world of mushrooms, looking in detail at low FODMAP mushrooms, as well as high FODMAP mushrooms. And how to incorporate them into your diet during the elimination and reintroduction phases of the low FODMAP diet.
What Are Mushrooms?
Mushrooms, as fungi, are biologically different from plant and animal derived foods, although they are typically classified as a vegetable for food grouping. They are in fact the fruiting bodies of macroscopic filamentous fungi that grow above the ground. More than 2000 varieties of mushrooms are edible and the most eaten mushroom in the world is the white button mushroom.
The Health Benefits of Mushrooms
Mushrooms offer a unique nutrient profile that supports a variety of health benefits and contributes to improved diet quality. They are rich in essential nutrients, such as B vitamins, selenium, potassium and fibre, addressing some common dietary deficiencies.
Mushrooms contain ergosterol, which converts to vitamin D2 upon exposure to UV light, enhancing their nutritional value. This could be especially beneficial for those with limited sun exposure or are otherwise at risk of vitamin D deficiency.
Research has indicated potential health benefits such as immune support, anticancer properties and improved metabolic health. They contain bioactive compounds with antioxidant and anti-inflammatory actions. For example, ergothioneine, another unique compound found in mushrooms, acts as a potent antioxidant. More recently, mushrooms have been highlighted for their anti-aging properties.
Some studies of limited quality have found that diets including mushrooms, categorised as ‘healthy plant-based’ improve cognitive function, mood and sleep and reduce the risk of all-cause death, dementia and depressive symptoms in diverse populations. However, it is unclear if the effect is due to the plant-based diet or the use of mushrooms themselves.
For individuals following plant-based diets, mushrooms serve as an excellent meat substitute due to their umami flavour and meaty texture. Their sustainable production further enhances their appeal as a nutritious and environmentally friendly food choice. making mushrooms a valuable component of a balanced diet.
What Are FODMAPs?
FODMAPs stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols. They are short-chain carbohydrates that can be poorly absorbed in the small intestine and are prone to fermentation by gut bacteria.
The low FODMAP diet was developed by researchers at Monash University. It has been shown to reduce symptoms of Irritable Bowel Syndrome in up to 86 % of people with IBS. It is designed as a second line diet for IBS after trying to improve symptoms with traditional dietary advice for IBS.
Are Mushrooms Low FODMAP?
If you’re trying to follow the low FODMAP diet, you might have found a huge variety of mushrooms that have been tested for FODMAPs by Monash University. But it may have left you feeling confused about which are the low FODMAP mushrooms.
Unfortunately, the majority of mushrooms are not low FODMAP or FODMAP friendly and can cause symptoms in IBS for many sufferers. Why are mushrooms high FODMAP? They are mostly high in the polyol mannitol, with the polyol sorbitol and fructans occasionally cropping up.
Mannitol is a polyol (a sugar alcohol) that can contribute to IBS symptoms due to its role as a fermentable carbohydrate. It is also present in other foods, including watermelon, cauliflower, celery, butternut squash, sweet potato and mange tout.
Sorbitol, another polyol, is less common in mushrooms and present in only chanterelle mushrooms. Other foods high in sorbitol include the fruits apple, blackberry, coconut and nectarines, as well as sweetcorn.
Low FODMAP Mushrooms
Fresh Oyster Mushrooms
Oyster mushrooms are low FODMAP in any amounts, making them a great staple in your diet if you’re following a low FODMAP diet or if you already know you are sensitive to mannitol and need to avoid other mushrooms.
They have a mild, delicate flavour that is often described as slightly sweet with a hint of anise. Their taste is subtle compared to more robust varieties like shiitake or portobello. The texture is tender and velvety, becoming slightly chewy when cooked. The texture can vary depending on the variety, with some being more meaty than others.
Oyster mushrooms are great as a meat substitute in plant-based recipes due to this texture. However, they are low in protein so this would need to be provided from an alternative source. They can be stir-fried, grilled and made into soups and stews, amongst other uses.
Canned White Button Mushrooms / Canned Champignon Mushrooms
White button mushrooms when fresh are high in the FODMAPs mannitol and fructans, however canned mushrooms are suitable on the low FODMAP diet. But why are canned mushrooms low FODMAP? Well, when they are canned, the water soluble FODMAPs leach out into the water. This makes drained canned button mushrooms low FODMAP mushrooms in a generous serving size of up to 250 g.
Canned white button mushrooms have a mild, slightly salty flavour due to the brine in which they are packed. The taste is less earthy and more neutral compared to fresh mushrooms, as some of the natural flavours are diluted in the canning process.
The texture of canned white button mushrooms is softer and more uniform compared to fresh mushrooms. They are tender and can sometimes be slightly rubbery, depending on the canning process and storage time.
Canned button mushrooms, as well as being low FODMAP mushrooms, are convenient and versatile so can be used in quick and easy recipes. Some ideas include use in soups and stews, pasta or rice dishes, in salads, stir-fries and casseroles and in sauces and gravies.
Shimeji Mushrooms
Fresh shimeji mushrooms are suitable on a low FODMAP diet in amounts of up to 750 g as they have been found to contain no FODMAPs. They are more of a speciality mushroom and it may be tricky to find them.
Shimeji mushrooms have a slightly nutty, umami-rich flavour with a hint of bitterness and a firm and crunchy texture when raw. Cooking them removes the bitterness and a savoury, buttery taste develops, making them a flavourful addition to various dishes. On cooking they maintain their shape and firmness, adding a pleasant bite to dishes.
They are versatile and can be used in many dishes, including stir-fries, soups, stews and rice dishes and can be added to salads or used as a garnish due to their attractive appearance.
Mushrooms with a Moderate FODMAP Serving Size
Dried Porcini Mushrooms
Porcini mushrooms, also known as penny bun mushrooms, when dried are high in mannitol in large amounts. However, a moderate serving size is 15 g, which is 2 tbsp. This amount is low enough in FODMAPs to be suitable for use in a dish, as long as you avoid any other moderate FODMAP foods in the same meal.
Dried porcini mushrooms have a rich, deep, and earthy flavour with some nuttiness and a hint of smokiness. Their umami intensity is increased compared to the fresh mushroom, making them a powerful flavour enhancer in various dishes. When rehydrated, dried porcini mushrooms become tender but retain a slight chewiness. The rehydration process also helps release their concentrated flavours into the soaking liquid, which can be used as a flavourful low FODMAP mushroom broth. They can be added to many meals to add their unique flavour, including soups, stews, risotto, sauces, gravies and in many vegetarian or vegan recipes.
Slippery Jack Mushrooms
Slippery Jack, or sticky bun, mushrooms have a decent moderate FODMAP serving size of 61 g, about ¾ of a cup. In larger amounts they are high in the FODMAP mannitol. Again, you would need to ensure you avoid other moderate FODMAP portions of foods in the same meal to avoid potential IBS symptoms.
Slippery Jack mushrooms have a mild, slightly nutty flavour with a subtle earthiness. Their taste is relatively delicate compared to more robust mushrooms, making them versatile for various culinary applications.
When fresh, Slippery Jacks have a slippery, sticky cap surface, which gives them their name. The flesh is firm and spongy. After cooking, they become tender with a slightly chewy texture. The sliminess of the cap disappears, making them more palatable.
Slipper Jacks are used in many European and Russian recipes and are suitable in a variety of dishes. They can be fried, used in soups and stews, pickled, used in stuffings and sauces and in rice dishes.
High FODMAP Mushrooms
Button Mushrooms (Champignons)
Fresh button mushrooms are the most commonly eaten mushrooms in the world. Unfortunately, they are also high FODMAP mushrooms in their fresh form. They contain large amounts of mannitol and are the only mushroom so far tested to contain fructans. This means that they would need to be tested separately to see if you are able to tolerate them, even if your mannitol challenge has been successful in showing no symptoms.
White button mushrooms have a mild, earthy flavour that becomes more pronounced and savoury when cooked. Their taste is often described as slightly nutty and subtle, making them versatile for a variety of cooking method. They retain a slightly chewy texture when sautéed or grilled. They are great to use in stir-fries with rice or quinoa, in casseroles and in soups.
Shiitake Mushrooms
Unfortunately fresh shiitake mushrooms are high in FODMAPs as they contain large amounts of mannitol. They have a moderate serving size but it is too small, at 17 g (or just over half a mushroom), to be worth using.
Shiitake mushrooms have a rich, savoury flavour with strong umami notes. Their texture is firm and slightly spongy. When cooked they become tender and maintain some chewiness. They are used in a wide variety of dishes, especially in Asian cooking.
Dried shiitake mushrooms are also high FODMAP mushrooms, with large amounts of mannitol. They have a low FODMAP serving size of 7 g, however this only equates to about 2 dried mushrooms, which makes them unsuitable during the low FODMAP diet.
Shiitake mushrooms are a valued ingredient for their intense flavour and versatility, enhancing a wide range of dishes with their rich umami profile. They are a staple in many cuisines and are particularly prized in Asian cooking for their ability to elevate the taste of many dishes.
Enoki Mushrooms
Fresh enoki mushrooms are high in mannitol. They have a moderate serving size of 12 g, or 3 medium sized mushrooms, otherwise are considered high FODMAP mushrooms.
Enoki mushrooms have thin, long stems and small, white caps that give them a distinctive appearance. They are prized for their unique texture and mild flavour, making them a versatile ingredient in a wide range of culinary applications. They are especially popular in Japanese, Korean and Chinese cuisines, where they are used to enhance soups, stir-fries, and salads.
Dried Black Chanterelle Mushrooms
Chanterelle mushrooms, or black trumpets, when dried, are unique in that they are high in the polyol sorbitol, whereas most mushrooms are high in mannitol. These may be a suitable option for you if you discover a sensitivity to mannitol, but not sorbitol.
Dried black chanterelle mushrooms are a highly prized ingredient in gourmet cooking, valued for their intense flavour and versatility. Chanterelles have a rich, earthy flavour with subtle smoky and fruity undertones. Their taste is more intense when dried, adding depth to various dishes. They need to be soaked before using in dishes but have a wide range of uses, including adding a meaty texture and umami flavour to many recipes, such as soups, stews, risotto, stuffings and sauces.
Portobello Mushrooms
Why are portobello mushrooms low FODMAP? Fresh portobello mushrooms, also known as portabella or giant cremini mushrooms, are high in mannitol and are unsuitable on the low FODMAP diet in amounts over 15 g. With one portobello mushroom weighing about 85 g, it really isn’t worth using them while you’re following a low FODMAP diet.
They are widely used in vegetarian and vegan dishes as a meat substitute for their meaty texture and their size means they are perfect as a burger substitute. They have a rich, earthy flavour with pronounced umami notes. Even after cooking they retain their texture and become tender and juicy. They are good for grilling and stuffing due to their large size, but can also be chopped up and used in a variety of ways.
Red Pine Mushrooms
Red pine mushrooms, also known as saffron milk caps, are high in mannitol in amounts over 27 g. This makes them high FODMAP mushrooms at a reasonable serving size.
They have a distinctive, robust flavour. They offer a slightly nutty and earthy taste with hints of fruity and spicy notes. Their flavour is rich, savoury, and can have a slightly resinous quality. When cooked, they become tender but retain a firm and crunchy texture, which makes them suitable for various cooking methods. They are particularly used in Mediterranean and Eastern European cuisines.
Swiss Brown Mushrooms
Swiss brown mushrooms are another high mannitol mushrooms, therefore unsuitable on the low FODMAP diet in any amount.
Also known as cremini or baby bella mushrooms, Swiss brown mushrooms have a slightly deeper and earthier flavour compared to white button mushrooms. Their taste is mild, with a subtle nuttiness and rich, savoury undertones. They are versatile and can be used in a variety of dishes from simple sautés to elaborate casseroles as their firm texture holds up well with various cooking methods.
Lion’s Mane Mushrooms
Lion’s mane mushrooms (Hericium erinaceus) are edible mushrooms found mainly in East Asia. They have been widely used as a food and herbal medicine in traditional Chinese medicine. They are known for their strong bioactive properties and have potential to be used as a neuroprotective agent. Supplement use based on medicinal mushrooms is still in very early stages of development and further research is needed to evaluate the effects and safety of its use.
Some studies investigating Lion’s mane mushrooms have shown improvement in mood and cognitive function with daily supplemental use. It is the only mushroom to so far show beneficial effects, which were only see in middle-aged and older adults.
Lion’s mane powder is low FODMAP in the serving size of 2 g, which is around the standard size of supplements available. It contains both mannitol and fructan, so care would need to be taken over the use in case of sensitivity to either FODMAP.
Studies investigating the effects of Lion’s Mane have typically used up to a maximum of 10 g per day. Even this amount is significantly lower than the moderate FODMAP serving size of 115 g.
What Can I Use Instead of High FODMAP Mushrooms? Mushroom Alternatives.
If you get bored of using the same low FODMAP mushrooms (oyster, canned white button and shimeji mushrooms) or you can’t find them easily, you can get a similar taste and texture from the following alternatives on a plant-based diet.
Low FODMAP plant-based mushroom substitutes:
- Tofu
- Tempeh
- Aubergine / eggplant
- Courgette / zucchini
Try leaving them to marinade, then roast or stir-fry. They all soak up flavours well due to their spongy texture, which is similar to mushrooms. You can add flavour with the following low FODMAP marinade ingredients:
- Soy or tamari sauce
- Lemon or lime juice
- Garlic infused olive oil
- Herbs
- Mustard
- Coconut milk (up to 60 g)
- Tomato puree (up to 36 g)
- Vinegar (rice wine, red wine, balsamic, apple cider)
- Maple syrup
- Sweet chilli sauce (up to 40 g)
- Sweet and sour sauce
- Satay sauce (up to 40 g)
Reintroducing Mushrooms After The Low FODMAP Diet
The low FODMAP diet isn’t forever, as it may potentially lead to unnecessary restrictions and nutrient deficiencies as well as a reduction in healthy gut bacteria. Once you’ve tried the elimination phase of the low FODMAP diet for 2-4 weeks, start reintroducing foods high in FODMAPs in a structured way. The best results have been found using the support of a specialist Dietitian to help optimise your health and gut symptoms. With mushrooms, the reintroduction of mannitol is the most important one to determine your mushroom tolerance.
If you find after reintroduction that you can tolerate mannitol, you should be able to eat the following mushrooms: button, fresh and dried shiitake, enoki, portobello, porcini, red pine and Swiss brown mushrooms.
On the other hand, if you can tolerate sorbitol but not mannitol, you should be able to eat dried black chanterelle mushrooms.
If you are lucky enough to be able to tolerate sorbitol and mannitol but have sensitivities to some fructans, be careful eating button mushrooms as they contain fructans. They would need to be tested separately during the FODMAP reintroduction phase.
Conclusion
Mushrooms are a unique and nutritious food that offers a variety of health benefits, including essential nutrients and bioactive compounds with antioxidant and anti-inflammatory properties. Despite their widespread use and popularity, most mushrooms are high in FODMAPs, particularly mannitol, sorbitol, and fructans, which can cause symptoms if you have IBS.
However, there are several low FODMAP mushrooms available for those following a low FODMAP diet which may improve your gut worries. Fresh oyster mushrooms, canned white button mushrooms and shimeji mushrooms can be enjoyed without triggering IBS symptoms. These varieties provide versatile options for cooking and can serve as excellent additions to or meat substitutes in plant-based diets.
For those with moderate FODMAP tolerance, mushrooms like dried porcini and slippery jack can be consumed in controlled portions. Understanding and selecting the right type of mushroom is crucial for managing a low FODMAP diet effectively.
Incorporating mushrooms into your diet, whether low or moderate FODMAP, can contribute to overall health and dietary diversity. Always remember that the low FODMAP diet is not meant to be permanent. Teintroducing high FODMAP foods, including various mushrooms, should be done gradually with professional guidance to ensure optimal health and well-being. If certain high FODMAP mushrooms can be tolerated after reintroduction, they can add rich flavours and textures to your meals, enhancing both nutrition and food enjoyment.
If you’re looking for a Dietitian to help support you in the low FODMAP diet and beyond, book a free discovery call with me here.
I really hope you found this article on low FODMAP mushrooms useful. Please let me know if you have any questions. I would love you to join my mailing list so you can get plant-based IBS updates and information from me, a Registered Dietitian specialising in IBS and gut health.
