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.
Sharon Pavey says
September 26, 2018 at 12:12 pmThis 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 !
Alana Scott says
September 26, 2018 at 9:43 pmHi 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!
Lucky_Strike says
January 10, 2019 at 2:02 pmHi! 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?
Alana Scott says
January 12, 2019 at 7:14 amThanks 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/
Janet says
November 9, 2019 at 7:25 amThis is so helpful thanks. A sneaky little problem that recurs for me’.
Kimberly says
January 14, 2020 at 12:04 amHi! 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!!
Alana Scott says
January 17, 2020 at 12:52 amHi 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.
Patricia Mass says
June 6, 2020 at 9:58 pmWhat about celery juice?
Alana Scott says
June 6, 2020 at 10:09 pmHi 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.