Dances with Dieticians: Learning more about Fructose Intolerance

I’ve been worrying about fructose intolerance for some time now.  Not worrying that I have it – I’m fairly sure that I don’t, and it would take a pretty high level of symptoms to drive me away from my fruit in any case – but worrying because I don’t understand it and I’m terrified of feeding someone the wrong thing (or giving them the wrong advice, not that anyone in their right mind would take dietary advice from me, I hope) and making them sick.

So – good grief, four months ago now, I am so slack – I decided to finally try to get a handle on this.  Exploring the Shepherd Works website led me to actual peer-reviewed published information about fructose intolerance and FODMAPs, which relieved my mind no end, because one of the biggest difficulties I’ve had with figuring out fructose is that everyone writing about it – even people who seem to be writing quite sensibly and scientifically – seems to have very strong opinions about it, and many of these opinions conflict with each other or are about how everyone else is wrong, wrong, wrong.

But one has to start somewhere.  I emailed Shepherd Works and asked if I could speak to a dietician sometime about fructose intolerance, explaining that I was a blogger, not a prospective patient, but that I really did want to get this right. And a few days and phone calls later, I found myself in a telephone appointment with a Katherine who knows much more about Fructose than I do.  And who likes food!  (You have no idea how terrified I was about talking to a dietician – the only one I’ve spoken to previously seemed to view food as the enemy, and I was entirely traumatised by the experience.)  This is vital.

Actually, before I go any further, I do want to stop and make one thing very clear.  While I took extensive notes during this conversation, and was quite fascinated by some of the information Katherine imparted, I am in no way an expert on nutrition (and really, a brief glance at the sheer volume of sweet recipes on this website should make that obvious).  What I am trying to do here is write up my conversation and provide people who do not have fructose intolerance but who might have friends who do with a reasonable starting point.  If you have fructose intolerance, please, please don’t use anything I write here as a substitute for consulting a dietician.  And if you have friends or family with fructose intolerance, while I hope that this will serve as a useful starting point for you, your best bet when catering for them is still to check with them what they are comfortable eating.  Everyone has different abilities to tolerate fructose and other FODMAPs (of which more later), and it’s important to *listen* to what people with an allergy or intolerance say about what they can and can’t eat, and respect that, not go believing random bloggers who may or may not know what they are talking about.

And I’ve bolded that, because for all my writing about how to vary recipes to make them suitable for different dietary requirements, that is probably the most important thing I can say about cooking for people food allergies, food sensitivities, or any other ethical or health issues around food.  (In fact, it’s probably a pretty good foundation for life in general, to listen to what people say, pay attention to their boundaries, and grant them the respect of assuming that they know their own needs better than anyone else does.)


One thing that Katherine mentioned early in the consultation is that the goal is *not* to keep people on restrictive diets, but to work out which fruits and vegetables they could cope with, and essentially work out the point at which symptoms are manageable but dietary variety is maximised.  This is a philosophy I can entirely get behind, probably because the very idea of fructose intolerance and giving up lots of fruit and vegetables makes me want to cry…

We started by talking about what fructose malabsorption was, and the difference between allergies and sensitivities.  I hadn’t previously realised that fructose malabsorption was essentially the same as Irritable Bowel Syndrome, and that it can thus be exacerbated by things such a stress, over-eating or eating late at night.  Unlike allergies, which are systemic immune reactions and can be life-threatening, fructose malabsorption can make you extremely uncomfortable, but it won’t kill you.  Fructose malabsorption is also distinct from conditions such as coeliac disease, where even tiny amounts of contamination with gluten (and good grief, even a fan-forced oven that has been used to bake products containing gluten can be a threat) will build up over time to cause issues.  In short, you are not going to poison someone with fructose malabsorption by feeding them food that once touched an apple, or even by feeding them a small amount of apple, though they won’t thank you for the after-effects.

In fact, while the list of problem ingredients is longer than that associated with many other dietary requirements, fructose malabsorption is actually rather low-stress in the sense that you aren’t going to send anyone to hospital if you get it wrong.  And that should be a weight off your mind.

Katherine then talked about FODMAPs.  This increasingly popular acronym stands for Fermentable Oligo-, Di-, Mono-saccharides and Polyols, which I’m sure you find just as enlightening as I do. My personal favourite thing about this acronym is that it doesn’t actually stand for any words I find useful – the actual list of FODMAPs is fructose, lactose, fructans, galactans and polyols, which still isn’t a terribly obvious or helpful list, but does at least contain a few words that non-scientists might have heard of!  But I suppose FLFGAP doesn’t make a very good acronym (though I feel one could make a good case for a mnemonic such as Fluffy Little Gorillas From Paris…).

Essentially, the FODMAPs are a collection of carbohydrates, sugars and alcohols that people can be difficult for the digestive system to absorb.  At one end of the scale, there are things like the galactans, which aren’t actually absorbed very well by anybody (think legumes – and their windy reputation).  Polyols, likewise, tend to be something that most people don’t cope with in large quantities (see, for example stonefruit – such as prunes).  At the other end of the scale, lactose and fructose tend to be problematic only for people whose guts are a bit more sensitive in the first place – but these people are also going to have issues with polyols and galactans and the like, and these are likely to affect them more strongly than they would the general population.

Which kind of sucks.

So if you are the sort of person who has difficulty absorbing fructose, you will often be recommended a diet low in FODMAPs, rather than just in fructose, because you don’t want your sensitive inner bits to have to work any harder than they have to.  And, of course, it’s also a good plan to try to avoid things like the aforementioned stress, overeating, or eating late at night, because these are also things that make your gut sad. And nobody wants to be a misery-guts.

Katherine very kindly sent me a list of FODMAP foods, but since I’m not sure whether I’m permitted to reproduce it here, I’ll just give you the brief highlights.  I did notice that the Monash University / Sue Shepherd group seem to be active on the Wikipedia page for Fructose Malabsorption, so that’s not a bad place to look for more information either. (And Australians should be aware that the conversation about fructose differs a lot between here and the USA, simply because we don’t have the same tendency to have high-fructose corn syrup in all our pre-prepared goods – I have it on good authority that fructose is not a poison and does not cause obesity any more than anything else eaten in excess does.)

Fructose – mostly found in fruit, particularly apples, pears, figs, and many dried or tinned fruits.  Citrus, berries, bananas and rhubarb are OK in moderation, as are many tropical fruits.  Also found in asparagus.

Lactose – found in dairy products such as milk, cheese, and yoghurt.  Hard cheese seems to be the lowest in lactose, and skim milk the highest.

Fructans – malabsorbed in everyone and particularly likely to lurk in legumes and members of the onion family, as well as in wheat.

Galactans – malabsorbed in everyone, and once again, the legumes are key offenders.  Poor legumes.  I still love you.

Polyols – partially absorbed in everyone, and frequently found in all those sugar substitutes ending in ‘ol’ – think xylitol and sorbitol.  I always suspected sugar substitutes were evil and now I know!  Polyols also tend to hang out in mushrooms and cauliflower.

I then asked about spelt, about which I have had conflicting reports, and Katherine went into a truly fascinating and illuminating explanation of the Spelt Issue.  It turns out that spelt, as a variety of wheat, is just as bad for someone with coeliac disease as regular wheat.  People with wheat allergies need to be careful about spelt, too, though some people can manage one and not the other.  And spelt is fine for people with fructose intolerance if – and I absolutely love this if – it has had a chance to rise.  So spelt bread, or spelt flour baked into a cake, are both fine, but spelt flatbread cooked in a frying pan is not.  This is possibly the coolest food fact I know.  Essentially the process of leavening breaks down the proteins in spelt just enough to render it low fructose.  I always suspected that baking was a form of magic, and now I know it is true…

Oats are also fine for people with FODMAPs, but not with Coeliac disease, and rye is full of fructans *and* gluten, so it isn’t too useful for either.

I got the gossip on non-dairy milks and coconut oil, while I was at it.  Apparently, all those lovely organic nut milks and oat milks that one gets at the supermarket may well be organic, but they aren’t a good dairy substitute in terms of calcium – the non-organic brands are generally fortified with calcium, but the organic ones work under different rules, and can’t be fortified at all.  So that’s something to bear in mind when you are buying your non-dairy milks – I suspect what you should buy depends on what your priorities are, but don’t assume that your milk has calcium in it unless it says so.

If you are avoiding FODMAPs, incidentally, you should also avoid wholebean soymilks, because of the aforementioned galactans.  But coconut milk seems to be fine, though a bit high in cholesterol.  Incidentally, I hadn’t realised that Copha was coconut oil too (I always rather suspected it was made of candle wax, actually.

We went into a cheery digression regarding the wonderful world of glucose matching, which is apparently not scientifically proven, though there is good anecdotal evidence for it. This is essentially about balancing glucose and fructose, because generally, if the sucrose to fructose ratio in something is at least 1:1, it’s going to be OK for someone with fructose intolerance. The basic sugars one buys at the supermarket are sucrose, which is 1:1 glucose to fructose, so obviously adding any fructose to a dish containing table sugar will push it over the edge – but if you have pure glucose syrup, you can use this to bring a fruity dish back to a point where it is fructose friendly.

Of course, at this point, it will be very sweet and not recommended by any sensibly nutritionist, but it’s useful knowledge to have in theory, I think.

All in all, a fascinating and useful conversation to have.  Lots of information, lots of science, and lots of love of food.  If you are in the market for a dietician, especially one who is knowledgeable about food sensitivities, I would definitely recommend the Shepherd Works group.

And yes, I need to re-vamp my Low Fructose page in a big way – please stay tuned for updates!

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3 responses to “Dances with Dieticians: Learning more about Fructose Intolerance

  1. This was useful Catherine so thanks for inquiring and blogging. E.g. I now understand why I can eat spelt bread but spelt pasta is a no go. Also my probs with onions and wheat mean fructans are not fun for me. Some days I think I should just live on steak and cabbage or fish and chips.

    • Oh, interesting! I hadn’t thought of the pasta aspect. I think the onions would be the hardest to manage, personally speaking.

  2. I’m really glad you found the appointment so useful! Melbournian FODMAP folks are very lucky – the main research on FODMAPs is being done at Monash Uni so we’ve got access to the people in the know. Both Shepherd Works and Diet Solutions dietitians are fantastic for this stuff.

    You’ve done a really good job of explaining a lot of stuff, but I hope you don’t mind if I correct a couple of things?

    First, fructose malabsorption/FODMAP sensitivity isn’t the same as IBS, it’s a leading cause of it. While about 75% of people with IBS respond well to a low FODMAP diet, there are people with IBS that’s distinct from FODMAP sensitivity. But, like all forms of IBS, FODMAP sensitive people experience worse systems and more sensitivity with stress et al (ask me about essay deadlines! :P)

    Also, people use the term “fructose malabsorption” rather than “fructose intolerance” in relation to FODMAP sensitivity – there’s a decent bit in the wiki article explaining why.

    For all that it’s one of the most well-researched food sensitivities, it’s still the most complicated in my book!

    Thank you for sharing that information about spelt! I haven’t been to a dietitian in a few years so I’m not up to date with the most recent research. Given the trouble I have with wheat I’m not sure I’m game to try it, but it’s interesting to know.

    Another nifty thing about FODMAPs is that they’re water soluble but not oil soluble. So garlic- or onion-infused oil is safe (as long as you remove all the plant matter) while making stock with onion then removing it isn’t. The water-soluble thing can be used to advantage, as well – if you soak dried legumes for a long time before boiling they end up lower in galactans. (I still love legumes too. I miss them. I can have some hummus every now and then, but gosh I’d kill for a giant chickpea curry…)

    Monash Uni recently released an app for FODMAPs (which I will forever call the FODMapp) that’s got a lot of great info:

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