Fructose Malabsorption and Fructose Intolerance

Fructose Malabsorption and Fructose Intolerance

Or how raisins kicked my butt!

A woman holding fruits and diarrhea pills.
Most of the time fruits can be good for you, but not if you are chasing them with diarrhea pills.
© Can Stock Photo

Fructose malabsorption or fructose intolerance basically means that your body has problems digesting fructose. Fructose is the sugar in fruit and lots of other foods. It was one of the last pieces of the IBS puzzle for me and may be important for you.

Here’s what happened to me, is it happening to you?

I stopped eating all kinds of junk food and put together a good, healthy diet. I admit I used to have terrible eating habits. So I added all kinds of fruit, nuts and lean meat etc.

I added lots of fruits because I’ve never been good about eating vegetables. Besides fruit is supposed to be good for you, right?! And it usually is…

But my IBS symptoms started to get worse!

So back I went back to the food elimination diet .

And unbelievably the trouble turned out to be the large amounts of fruit (or fruit sugar) I was eating!

I could eat a banana and a couple of apples, but throw in a cup of raisins, and I felt like my guts were in a grinder!

My Gastroenterologist (the gut doctor ;) told me that fructose causes trouble for a lot of people. I wish he had mentioned it earlier :(.

It turns out that I can tolerate some fructose, but when I eat raisins or other high fructose foods (especially without anything else), I get very sick with IBS symptoms.

What’s the difference between fructose malabsorption and hereditary fructose intolerance?

Sign saying fructose intolerance
© Can Stock Photo

First of all, it really is fructose malabsorption with a P, not malabsorbtion with a B, even though the P just looks wrong to me.

Either way, the medical establishment changed the name to avoid confusion with a condition called “hereditary fructose intolerance” which is very similar to fructose malabsorption.

In both cases the body has trouble digesting fructose, which causes all the symptoms of IBS (except constipation).

The difference is that hereditary fructose intolerance is a genetic problem that runs in families.

Hereditary fructose intolerance causes all kinds of health problems for children including IBS symptoms, vomiting, jaundice, poor appetite, sleepiness and more. It affects about 1 in 10,000 people (so it’s pretty rare), and it’s there from birth.

Fructose malabsorption is MUCH more common. At least 30% of the population (3 out of 10 people) or even more, have some level of fructose malabsorption.

Also fructose malabsorption can develop over time and worsen as people get older (like everything else ;).

Why you need to know about fructose malabsorption and fructose intolerance:

Man with belly pain and toilet paper
Fructose intolerance can keep you heading for the toilet.

A study published in “The American Journal of Gastroenterology” shows that a HUGE number of people with IBS symptoms have may have problems with fructose.

Researchers tested 50 men and 133 women (183 total). 101 tested positive for fructose intolerance. That’s more than half the people!

When the people in the study drank water mixed with fructose, they got:

Water mixed with fructose??? Just about every drink you can by at the store is water mixed with fructose. Iced tea drinks, soda, juice, etc. Is this where many or all of your symptoms are coming from?

Research on fructose malabsorption shows that some people can digest small amounts of fructose, others can digest a bit more, and some people can’t handle fructose at all.

UPDATE: Avoiding fructose may cure your IBS symptoms!

According to another study I just found in the Journal of Clinical Gastroenterology, about one-third of patients with suspected IBS really had some form of fructose intolerance! When those people stayed on a fructose-restricted diet there symptoms improved or disappeared; Some of them couldn’t stand being on the fructose-restricted diet, and their symptoms stayed the same. Fructose intolerance is another piece of the IBS puzzle that may respond to dietary changes!

What is fructose and where is it hiding?

Fructose is the sugar found in fruit. It’s also in fruit juice, and is added in all kinds of foods and drinks as a sweetener. Check the labels and you will see it in lots of places.

A very common form is called “high fructose corn syrup” which seems to be in just about everything these days.

Fructose is often used as a sweetener to make food sound healthier (i.e. sweetened with “natural fruit juice,” etc.). Some manufacturers may actually believe that it IS healthier.

In some cases (like high fructose corn syrup) it is a LOT cheaper to use fructose to sweeten things.

Picture of fresh fruits.
Some of the best food, or some of the worst food. It all depends on how your bowels handle it.
© Can Stock Photo

Fructose hides in lots of foods as:

  • High-fructose corn syrup
  • Table sugar (sucrose)
  • Confectioner’s sugar or powdered sugar
  • Fruit and fruit juices
  • Honey
  • Regular soda
  • Flavored water
  • Sorbitol (a sugar substitute known to cause diarrhea)
  • Sports drinks and bottled iced tea
  • Wine
  • Many other foods (make sure to check the label for fructose, etc.)

Different foods have different amounts of fructose.

If you have trouble with fructose malabsorption, you (and hopefully your doctor or nutritionist) will need to figure out how much your body can handle, or cut out fructose entirely.

Why does fructose malabsorption cause problems?

If you eat or drink more fructose than your small intestine can absorb, then the remaining fructose travels into the large intestine (the colon or large bowel).

The fructose attracts water, which leads to loose stool and/or diarrhea. Yeast and bacteria that live in the digestive tract eat the fructose, and give off hydrogen, methane and other gasses.

All of this can set off an attack of IBS symptoms.

Fructose Malabsorption Symptoms:

Fructose malabsorption causes all of the classic symptoms of IBS, usually leaning toward diarrhea rather than constipation.

Tests for Fructose Malabsorption:

The most common test for fructose malabsorption is the hydrogen breath test. That’s where you drink a fructose sweetened drink, and they check your breath for hydrogen and other gasses.

The medical people can use that information to see if you’re not digesting fructose properly.

Then of course there’s the food elimination diet , where you remove suspected foods for a little while, and then add them back one at a time to see if they cause problems.

Fructose Malabsorption or Fructose Intolerance Diet:

Some people can completely cure their IBS symptoms by eliminating fructose from their diet. For others (like me), it’s just one piece of the IBS puzzle.

Here’s what works for me, and maybe for you:

I find that I can eat medium amounts of non-sugary fruits, and small amounts of high fructose corn syrup (in barbecue sauce for instance). Also, If I eat fructose as a small part of a meal I’m fine.

No fruit juices, or syrupy drinks and no dried fruits.

If I eat too much fructose all by itself I’m in so much pain I feel like I need to go to the hospital!

Going all the way. Cutting fructose out of your diet.

If you can’t handle fructose at all, getting it out your diet is going to be a real challenge. You’ll to remove the items in the list above, and you’ll have to check food labels constantly. Fructose hides everywhere!

You should really talk to a Nutritionist to help you develop a plan. You don’t want to get sick (with malnutrition) while trying to get well.

Some other things you may need to know:

The Food Elimination Diet page has information about finding which foods may be sensitive to.

See the Food Intolerance page for other foods that may be causing you problems.

The Lactose Intolerance page – Lactose is a sugar like fructose that many (most) people have trouble digesting.

14 Replies to “Fructose Malabsorption and Fructose Intolerance”

  1. I came across this article because I’ve just found out for myself that I can’t tolerate fructose very well. I’ve been having bowel problems for the last 8 years which gradually got worse. I’ve blamed all kinds of things, artificial sweeteners, alcohol, wheat, antibiotics. I constantly felt like I needed the toilet and had a pain in my lower left abdomen. It got to a stage where I was terrified to leave the house in case I needed the toilet.

    A friend suggested that I might be lactose intolerant so I cut out milk and cream and yogurt (I can tolerate cheese really well thankfully as most of the lactose is eaten by bacteria during fermentation) it worked really well for me, I felt better but it didn’t cure me completely.

    In January 2018 I moved in with my girlfriend. She never eats fruit because she says it doesn’t satisfy her and it just makes her want to eat more food. Naturally I stopped eating fruit too as there wasn’t any around. After a few weeks I began to notice that my bowel condition was improving. Four months later I barely ever feel like I need to rush to the toilet. My diarrhea has cleared up and I don’t panic at all now when I leave the house. I’m having normal bowel movements and I can tell the difference between needing a fart and needing to poop.

  2. Makes sense. I’ve always had a weird thing about fruit and or fruit drinks. Not all the time though. Could just very well explain why my tastes for desserts are so different than anyone else.
    Like, I love pumpkin pie, but that’s pretty much the only one I will eat. I love donuts, but not with any sort of fruit type jelly in them. No pie with fruit in it. Once in a great while I might survive a slice of Apple pie, but why chance it right?

    Now at least I have an explanation , wish I had it for all those times my family, friends, etc would wonder what was wrong with me that I don’t like desserts that have fruit mixed up in them. Because they know how big of a junk food junkie I am

    Fruit doesn’t always cause me trouble, I mean in yogurt like activia I’m fine , if I eat fruits in the morning for breakfast on an empty stomach I’m fine although for some reason never seems to cure that hunger pangs (pains?) I just seem to get hungrier , like my stomach has some strange sarcastic negative personality that comes out growling even louder as if to say, OK very funny now give me some real food lol.

    Can’t drink any sort of fruit juice with food , but soda I’m fine with food or any time usually lol.

    Thanks for putting in words what I couldn’t but explains finally what makes me weird for choosing no desserts rather than one involving fruit and breads mixed. Maybe it’s the bread thing too
    Anyhow, I need to keep eliminating stuff out of my diet

  3. Hi there, I suffer from FM. I run marathons at a decent pace (3hr) and have really struggled to find gels/drinks that I can stomach without getting the dreaeded “runners trots”. Any suggestions please?


  4. hello to all. i have read many sites regarding this problem but i never really read common issues with myself. start old time ago with diet coke,soft drinks, candies, sugar juices, to pure fruit juices. i have really severe issues that none till now express and that makes me worry. since i am fructose intolerance same as many other as far i read none have the symptoms of severe headaches that i do. start in the morning around 9 they get worse at noon, after 5 pm seems the pain is gone 50% of the time. headaches keep me in bed from 1-3 days. sometimes nausea and vomit. terrible behind eyes pain, i avoid the light and the strong sounds. the only common as other describe is the bloating since i have 3 times large belly compare to my body.iam curious if there is someone with same symptoms. i dont have clinical prove of my issues since were i live docs doesnt know were headaches come from and i found it myself. if i avoid fructose life seems brighter:)

    1. Wow, that sounds awful, Demian. Those sound like my wife’s migraine headaches. I’m glad you found SOMETHING that helps. I’m wondering if it could be related to blood sugar??? I’ve read that high blood sugar or low blood sugar can cause headaches. I’ve also read that drinking or eating a lot of sugars (like fructose)or other carbohydrates, can cause blood sugar levels to bounce up and down. I wish that you had some competent medical help in your area. I’M SO GLAD SOMETHING MAKES LIFE BRIGHTER- Shawn

  5. Can some fructose malabsorbers tollerate onions and garlic or is it not even worth a try? i am a new diagnosis and on strict FODMAP illimination at the moment

    1. Hi Sam,
      From what I’ve read, onions and garlic are a no no for a strict fodmaps diet.

      Also onions and garlic are not recommended (in some places), if you have fructose malabsorption.

      Now, I’m not a doctor, or dietitian, but here is how I approach things like that. I wait until my guts are not giving me any trouble. Then I try the food (whatever it is), in small amounts and see if it causes me problems. Sometimes there is a BIG difference between a little of something and a LOT of something. I can actually eat very small amounts of wheat for instance, if it’s mixed in with lots of other food. Lots of wheat = unhappy Shawn.

      All that being said, neither onions or large amounts of garlic work well for me.

  6. Please change your sentence stating that FM causes IBS symptomes EXCEPT CONSTIPATION. FM most certainly can cause constipation. One of the studies I read concluded that FM was even more likely to cause constipation-predominant IBS than the diarrhea-dominant type.

    1. Hey there M.L.,

      I scoured the Internet for reliable information and studies that Fructose Malabsorption causes constipation. I couldn’t find anything reliable. I’m anxious to fix this if I have incorrect or incomplete information. If you could please provide me a link to the study, I would be grateful and correct this immediately!


      1. Hi Shawn,
        Just came across your site. I was diagnosed by Hydrogen Breath Test for Fructose Malabsorption nearly 12 months ago.

        I’d been having constipation and sometimes diarrhea but mostly stomach pains…I even had my gall bladder out! It may have been fructose all along!

        A very good gastro asked me some specific questions (can you eat onion…garlic?) …I have had big issues with these, and he said ” I think you may have a fructose issue” and sent me for a proper test.

        I’d never heard of it before but it certainly changed my like.

        Garlic is very very bad for me as is wheat. Fortified wines like port always made me feel sickly, now I know why.

        The sad thing is, many people diagnose themselves as “gluten intolerant” and that is only if you are a coeilac. It is more likely to be a wheat issue (eg fructose, fructans etc).

        Dr Sue Shepherd is a huge info source on this.

        But yes constipation can certainly be a problem with “frucmal”.

        And for us, an apple a day keeps the doctor in pay!

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