What is Mannitol?
Love sweet potato? But can’t tolerate large serves? Then you might have issues absorbing mannitol. Mannitol is a high FODMAP sugar alcohol and it belongs in the ‘Polyol’ group within the FODMAP acronym. This sneaky FODMAP occurs naturally in a range of fruits and vegetables, and it can also be manufactured and added to our food. Check out my article to find out where mannitol likes to hide.
Where is Mannitol Found?
Mannitol naturally occurs in high levels in a range of fruit and vegetables like watermelon, clingstone peaches, button mushrooms, cauliflower, celery, snow peas, butternut squash and sweet potato (1 2). It’s important to remember that many high FODMAP foods like butternut squash, sweet potato and snow peas, have smaller serves that are low FODMAP (explore the Monash Low FODMAP app for more information).
Mannitol can also be manufactured from fructose sourced from cornstarch (3). Manufactured mannitol is used as a sweetener and is added to a wide range of products from ‘sugar free’ foods and beverages, through to protein powders, baked goods, and chewing gum. It is also added to some liquid medications like cough syrups, cold medicine, and liquid pain relief.
Can Mannitol be Called Anything Else?
Check processed products for mannitol food additive number e421 or 421 (4). In the USA mannitol should be called by its full name in the ingredient list.
Why is Mannitol an Issue?
Mannitol is a polyol and only one-third of the polyols consumed are actually absorbed by our bodies. The level of absorption depends on the type of polyol and the individual. When polyols are poorly absorbed, our gut bacteria feast on the sugars and rapidly ferment them, causing IBS symptoms (1 5). Polyols are also natural laxatives, as they draw water into the large intestine when they are poorly absorbed, which stimulates bowel movements (1 5).
Do Mannitol Levels Vary Between Foods?
According to a research paper published by a Monash University research team in the Journal of Agricultural and Food Chemistry, the mannitol levels between different fruits and vegetables do vary. Below is a table with a few examples.
| High FODMAP Fruit | Grams of Mannitol per 100g of fresh weight of sample | Low FODMAP Serving Size |
|---|---|---|
| Clingstone peach | 0.52 | N/A |
| Watermelon | 0.24 | N/A |
| Vegetables | ||
| Butternut squash* | N/A | 30g |
| Button mushrooms | 2.63 | N/A |
| Cauliflower | 2.96 | N/A |
| Celery* | N/A | 12g |
| Fennel bulb* | 0.32 | 49g |
| Mange tout* | N/A | 17g (5 pods) |
| Snow peas* | 1.16 | 17g (5 pods) |
| Sweet potato* | 0.27 | 70g |
*These vegetables have small serves that are low FODMAP. N/A stands for ‘Not Available’.
(Information in table sourced from: Monash University App, 2016; Muir et al., 2009)
Can You Cook With Foods High In Mannitol?
During the first phase of the low FODMAP diet, make sure you avoid cooking with foods that are high in mannitol, unless they have a low FODMAP serving size (check the Monash Low FODMAP app for serving size guidelines). For example, in the low FODMAP phase you can enjoy a low FODMAP 75g serve of sweet potato. However, be careful when adding other low FODMAP serves of foods that also contain mannitol. For example, combining a full serve of butternut pumpkin and sweet potato in one meal, as this might take you over the FODMAP threshold level. Otherwise, it is recommended that you avoid cooking with foods that are high in mannitol (button mushrooms, cauliflower, clingstone peach, watermelon), instead focus on low FODMAP ingredients.
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Also keep in mind that mannitol is water soluble (6), just like the fructans in onion and garlic. This means that the mannitol will leach out of the food and into the liquid in the meal. For example, if you cook a soup using button mushrooms, the mannitol will leach out of the mushroom and into your soup, raising the overall FODMAP content. Even if you pick the mushrooms out of the meal you could still consume a high FODMAP load.
Final Thoughts
Mannitol is a sugar alcohol that can sneak into our diet through certain fruits, vegetables, and processed products. Make sure you check food labels for mannitol food additive name e421. During the first phase of the low FODMAP diet, make sure you avoid foods that are high in mannitol, unless they have a safe serving size.
Image Credit: mama_mia/Shutterstock.com
This is great. Thanks so much. After a few weeks on the low FODMAP diet I’m reintroducing mushrooms this week. Well I’m trying & seeing how we go! Wish me luck !
Hi Sharon,
I’ve got my fingers and toes crossed for you and really hope that your mannitol challenge goes well. Let me know how you get on!
Hi! What a wonderful page on mannitol, thank you very much. I have an intolerance for high levels of mannitol (and garlic and onion) unfortunately. I can eat some and it looks like the heating process might be of influence. Raw cauliflower is horrible for my intestines but steamed is ok if I don’t eat it two days in a row.
I have a question. In your list, it says butternut squash and button mushrooms. Does that mean that any other squash/pumpkin or mushroom is ok to eat?
Thanks for commenting. It’s great to hear that you can tolerate small amounts of mannitol and enjoy a bit of steamed cauliflower! Japanese Squash also known as Kombucha Squash or Buttercup Squash is low FODMAP and can be enjoyed. Many other mushrooms are high FODMAP so make sure you check out this article for more information: https://alittlebityummy.com/fodmap-guide-to-mushrooms/
This is so helpful thanks. A sneaky little problem that recurs for me’.
Hi! I’m now re-introducing and next week is mannitol week. I’m going to use cauliflower to re-introduce. Fingers crossed. Few questions for you: (1) I’m using the Monash approach and reintroducing small, medium, and large amounts of the food and then 100% FODMAP for the rest of the week. It’s worked well for fructose (which I can only take in small doses) and sorbitol (which I can take in all doses). My question for you, what is a small, medium, and large amount. I tend to go w/1/2 cup, 1 cup, and 1.5 cups. Is that right? (2) I’m using cauliflower for mannitol. Should I eat it raw or cooked? Many thanks!!
Hi Kimberley,
Thanks for messaging. With your cauliflower challenge I would look at doing a 2 floret serve, 1/4 cup serve (about 4 florets), and then a 3/4 cup serve and see how you go with that. With the challenge, think about how you would normally eat cauliflower. If you like eating it raw then you can challenge it that way. If you prefer it cooked, then cook it and add it to your meal.
What about celery juice?
Hi Patricia,
Celery juice is currently untested. However, we do know that juicing foods often concentrates the FODMAP content. This means we would recommend that you avoid celery juice until your symptoms are settled and then test your tolerance to a small amount.
Thank you for this advice. Mannitol is my worst FODMAP by far after I’ve been through the process and keep having to remind myself where it’s hiding in foods eg larger serving of celeriac. I love most of these natural mannitol-containing foods and it’s good to know some have a safe portion. Thanks!
I am new to learning about all these hidden things like Mannitol and learning to eat a Low FODMAP diet. Any tips to get started would be greatly appreciated. I have suffered from gas/bloating/and feeling like gas is trapped with abdominal cramps. I don’t get diarrhea or constipation, just lots of gas discomfort. I’ve pretty much eliminated all dairy. I’m hoping I’m moving in the right direction by trying the low FODMAP way. Any advice would help save me time and be appreciated. Thanks
Hi Jessie,
Thanks for commenting. We are happy to help you get started on the low FODMAP diet. What we’d recommend you do is check out our FODMAP Wellness Club – it has everything you need to make the low FODMAP diet easy all in one place. It gives you instant access to our FODMAP101 Course (this has everything you need to know to get started), downloadable guides, 700+ low FODMAP recipes, meal planning tools, symptom tracking tools, email tips and email support from FODMAP experts. You can also access a range of dietitian led classes that can help you troubleshoot your symptoms. You can find out more here: https://alittlebityummy.com/join-our-low-fodmap-club/
Hello, I’m very mannitol sensitive, and not sure about sorbitol yet. I read in lots of places that clingstone peaches are high in mannitol. Someone mentioned to me that freestone peaches might be more ok, but I can’t seem to find anything about freestone peaches, all the resources only mention clingstone. Would you have advise for me?
Hi Elaine,
Thanks for commenting. Monash University hasn’t tested freestone peaches for FODMAPs yet, this means we don’t know what the mannitol levels are in this fruit. We do know that white peaches and yellow peaches contain sorbitol and sometimes fructans. This means if you aren’t sensitive to these FODMAP groups you might tolerate those varieties better. You can find more information in the Monash University FODMAP Diet app.
Thank you for making this page. Would you have any thoughts on whether it might be the mannitol in this situation? If I make canned pureed organic sweet potatoes made by Farmers Market brand, I can eat about 70 grams in a meal (reheated either in a steamer or in oven). If I buy fresh sweet potatoes, peel them and then either boil them, or steam them, or bake them, or a combination of all of those … I have gut trouble starting in less than half a day. Have tried multiple varieties of sweet potatoes (but only tested purple once and am not sure yet if I reacted or not – I might not have to purple). Thoughts? I’m making my brain hurt trying to figure out the culprit. I so love sweet potatoes! Thank you so much. (Celiac and multiple autoimmune and other issues.)
Hi LM,
Thanks for commenting. We know that cooking methods can change the FODMAP content of foods, however we currently don’t have information on how much different cooking methods can change the FODMAP levels. Additionally, the effectiveness of cooking methods at reducing FODMAP content is likely to vary based on the ingredients. If you know that you can tolerate canned pureed sweet potatoes – then that’s great – you can keep eating those. The low FODMAP diet only needs to be as strict as needed to manage symptoms. When you are ready to do your mannitiol reintroduction challenge we’d recommend you try that using portobello mushrooms – if you react to those then you will know you’re sensitive to mannitol and that might be why you are reacting to sweet potato.
Thanks so much for the helpful article! I have just been given the diagnosis of IBS so this is all new to me, but making so much sense now!!
This also explained really well how the FODMAP ‘stacking’ can happen. Which was something I was a bit confused about. Thanks for sharing with us!
Hi Kelsie,
It’s great to hear you found the article useful. Thanks for commenting!
I am in the reintroduction stage and pretty sure Mannitol is one of my triggers. Just ate a very small amount of mushrooms and had almost instant reaction. Although had a small amount of pumpkin yesterday so could have been that 😢
Hi Julie,
Thanks for commenting. We are sorry to hear that you are potentially reacting to mushrooms. Just keep in mind that FODMAP reactions take place in the small and large intestines. This means if you have an instant reaction to a food, it’s often something else that was triggering it – either an earlier meal, a reflex that is triggered when a meal is eaten (this is more common if you have ‘instant’ reactions to meals all the time), or a different type of food intolerance or food allergy. To test that it is the mushroom causing this issue we’d suggest trying a smaller serving size on a day when your symptoms and stress levels are well managed. In terms of testing mannitol we’d also recommend trying a different food that contains mannitol and see how you go with that.
I have reflux issues and find that the antacids I need all have Mannitol in them, and so cannot have them.
Hi Christopher,
We are sorry to hear that you are reacting to the mannitol in antacids. We’d suggest you have a chat to your healthcare team as they might be able to prescribe an alternative medication.