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How do I know I have Fructose Malabsorption?
Fructose malabsorption is diagnosed with a fructose tolerance test. This measures hydrogen produced by gut fermentation, which is then absorbed into the bloodstream and exhaled on the breath. It is a simple test, that captures about 90% of cases. The remaining 10% typically produce methane instead of hydrogen. A test can also measure for that, but it may not always be available.
Some people self-diagnose with a food trial - removing the most at-risk foods from their diet for a period of time (4 days to 6 weeks), keeping a journal of symptoms, and then re-trying the offending foods to see what happens. While this gives a very good idea in many cases, it doesn't always capture the whole picture. However, when a breath test is negative, a diet challenge of this sort (usually with medical guidance) serves as the basis of a formal diagnosis.
A diet challenge or 'detection diet' is the final proof with your own body. As one doctor told us, the test is just a test, your body still 'knows' what does and doesn't work - even if we don't. Many of the best doctors will follow a negative screening test with a diet challenge to be sure either way.
What else could these symptoms mean?
Fructose malabsorption has symptoms that are very similar to 'classic' IBS, celiac disease, depression, and anxiety. It is always worth checking for celiac disease or other underlying conditions, since those can cause long-term physical damage to the body, and may be the underlying cause of the fructose malabsorption (by damaging the area where the fructose would have been absorbed). Rule out more serious long-term causes if possible.
It is also important to test for SIBO or SBBO (small bowel bacterial overgrowth), which can happen as a result of FM, or as a cause of FM. Bacterial overgrowth creates a layer of bacteria that block absorption of nutrients, including fructose, making matters worse. A round of antibiotics can trigger SIBO, by killing off the gut flora that would normally prevent the bacterial layer from forming. The same kind of testing (breath testing) can be done to rule out SIBO.
What symptoms might I have?
Symptoms may be gastrointestinal (about 50% of cases have some GI signs), including:
gas/flatus (often fairly bad smelling, but not always)
IBS or IBS with constipation
Constipation
'rumbling' in the belly
cramping
diarrhea or generally soft stools
reflux (reported by patients as 'may be worse after consuming polyols' in some cases)
sugar cravings and fruit cravings
fruit and vegetable avoidance (especially in kids, though this is hard to separate from normal pickiness)
Non-gastrointestinal symptoms (rate unknown, though may be present with or without GI symptoms)
depression (noted frequently in research, more common in female patients)
anxiety, may be worse after meals ('small bowel hurry')
mood disturbance related to low tryptophan absorption (fermentation blocks absorption of tryptophan, and low serum tryptophan is common in people with FM) (some people observe that the outbursts and anger type responses seem to be more common in males, but this may be culturally mediated - one young male patient had ADHD-like social behavior and mood swings/rages, which resolved with the diet change)
cycles of easy bruising or under-eye circles (also related to low serum tryptophan, which is needed to create serotonin, which support blood clotting function)
poor sleep (tryptophan is also necessary for normal melatonin production, so sleep difficulties may also be found)
Symptoms also noted in many children, but without known clinical cause:
joint pain
greater sensitivity to growing pains
What can I eat?
Both selectivity (choosing 'safer' foods) and moderation are key. The body can only absorb a certain amount of fructose at a time, and each body has its own level of 'acceptable' - so moderation has to be tested out individually. For some people, a 'normal' serving of fruit (1/2 cup) is fine, if they have only 1 or 2 servings per day (especially with other foods). For others, that is too much, and servings have to be smaller. Some people can have small servings more often. Also, adding glucose (dextrose) to a meal supports absorption of fructose. There's still a maximum limit, but to absorb fructose, glucose is necessary. Smarties candies (in the US, small roll of round, lightly colored candies) are a common source, but glucose tabs for diabetics, and dextrose powder (often sold for weight training) are fine sources of glucose. Eating foods that slow down digestion (fats, proteins) along with fructose-bearing foods can also help maximize absorption.
General guidelines:
- Meat, eggs, and fish are fine - no fructose.
- Cheeses and dairy are fine if there is no lactose intolerance, too.
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White rice is generally considered safe. Tolerance to other grains varies. Some examples of grains (and non-grain starches) that are tolerated by some, but not all, people with FM are: brown rice, refined corn meal and corn starch, 100% rye, spelt (which is an ancient variety of wheat, but is better tolerated by some than modern wheat), quinoa, teff, amaranth, potato starch, tapioca starch, buckwheat, and millet.
- In general, sour citrus (lime, lemon, some grapefruits) are reasonably safe to try. Other citrus will have individual tolerance levels, but are a good first choice.
- Some varieties of kiwi are fine, others are not (at least not without glucose).
- Banana may be tolerated.
- Some people tolerate pineapple.
- Some people tolerate apricots and other pit fruits (but these contain sorbitol, and some people react poorly to them).
- Most berries are tolerated well. Wild blueberries (the tiny ones) are an exception (very high fructose).
What can't I eat?
There are a few 'key' foods that should be avoided by everyone with this diagnosis.
- Onions
- Leeks
- Apples
- Pears
- Pit-fruits like peaches (if polyols are a problem - test individually!)
- Jerusalem artichoke
- Watermelon
- Mango
- Fructose, such as in High fructose corn syrup ('plain' corn syrup is fine, but check ingredients!) and corn syrup solids
- Honey
- Agave
- Wheat (both whole and white - note that in the US, guidelines still recommend white wheat flour as 'safe' - but this is without considering the fructan issue, and many people appear to do better off wheat. Note that this is not 'no wheat as an ingredient' but 'no wheat-is-main-ingredient' - small amounts of wheat as a lesser ingredient, or wheat-derived foods are fine. Dextrose is often wheat-derived, and it's safe.)
Beyond those, tolerance level may need to be tested individually. Fructose and glucose values of many foods can be found on Nutritiondata.com, and on the FDA website of the US government. Note that values are often averages, and may cover many varieties of any given food. There are few sources of information for polyol content, and nearly none for fructans (which vary based on conditions during growth, age of plant at harvest, storage, and so forth).
Monash University in Australia is the world leader in research on fructose malabsorption, and is constantly updating their listing of food fructose and glucose content, in relation to consumption by people with FM.
Can I eat out?
Yes! Gluten free meals are more and more common at restaurants, though not everything gluten free is safe, there are many more options available without wheat. Rice noodles and rice are staples of many ethnic foods, as are potatoes. Sauces often are an issue - high fructose corn syrup or other sweeteners can be present, plus onion and wheat. Usually a simple dish that is not breaded and is accompanied by a safer starch can be found.
Can I eat gluten-free?
Most gluten-free foods are fine, though some specifically gluten-free foods have enough bean flour to cause trouble for some individuals, or may be sweetened with fruit concentrates, agave, or honey.
How do I feed a child with fructose malabsorption?
It may seem frustrating, but it can be done! Picky eaters or kids with multiple other dietary or medical issues are the most challenging to work with. Consider seeing a feeding clinic or pediatric nutritionist - though be aware that many know little to nothing about Fructose Malabsorption, so you'll have to provide them with the basics and see what they can come up with - more of a team function than an expert guidance scenario.
Things that some kids have accepted as safer foods:
- dried cranberries (check to see how they're sweetened and still limit, - we use 5 as a max for now - but good source of vitamin C and fiber)
- blueberries (large type, not the small 'wild' type)
- clementine or mandarin oranges - trial for tolerance and quantity
- Thai-style or Chinese or Japanese rice noodles (white rice, not brown rice)
- kiwi (test varieties by size - the small ones seem to be tolerated better for us than the extra large)
- white rice (converted long grain, Chinese rice, basmati, jasmine rice (Thai rice))
- rye crisps (if rye is tolerated) with a thin layer of orange marmalade (again check the sweetener)
- bananas (ripe is better for fructose levels)
- rice/corn cereals sweetened with sugar
- corn puffs sweetened with sugar
- any meat or fish
- baked potatoes
- home-cooked fries (my kids have trouble with commercial fries, and one nutrition list shows commercial fries with a poor balance of fructose to glucose - trial quantities by child.)
- cucumber (in moderation)
- uncooked carrots (in moderation)
- summer squash (in moderation)
- gluten-free treats (checked for flour source and sugars - my kids don't do well with either a lot of soy flour or a lot of bean flour - but we've found safer pancake mix, brownie mix, biscotti, cereal, and rice bread they love)
Does this mean I can't eat fruit at all?
No. You can either choose 'safer' fruits, or add dextrose to 'less safe' fruits. Individual trialing of each fruit will help you figure out how much of what will work for you. Eating fruits with other foods is generally recommended.
What kinds of things set off the symptoms?
Some people have symptoms that are aggravated by more than just food. Warmer weather affects a portion of the population with worsening symptoms (reason unknown, but definite pattern).
Some people have symptoms that are aggravated by things that affect their other conditions, either as underlying causes or co-morbidities. For example, people who have recurrent or underlying yeast overgrowth are likely to get worse symptoms if they consume excess foods that feed yeast or (for some) foods that contain molds or yeast (bread, wine, cheeses).
Can I travel?
Yes. Some people find their symptoms may even improve while traveling, while others have worse symptoms. Being careful of the key ingredients is essential, and how severe your initial symptoms are may affect this choice. Travel to areas that use white rice over wheat as a staple may make life a little easier. Treating any underlying conditions (such as small bowel bacterial overgrowth or SBBO/SIBO) before travel may make the trip more comfortable, as well.
What other health problems might occur as a result of this?
Small bowel bacterial overgrowth (SBBO, or SIBO referring to small intestine bacterial overgrowth) can be associated with fructose malabsorption. This can also be an underlying cause of FM, first blocking absorption, and then interacting with the reduced absorption in a cyle that makes the infection more robust (more fructose to feed the bacteria).
Most symptoms are related to either fermentation directly (gas/flatus, osmotic diarrhea, constipation, cramping, bloating), or are secondary results of the process (such as inability to absorb tryptophan, which is needed for the body to create serotonin, leading to an imbalance of serotonin in the brain, which may cause depression, anxiety, and mood disruptions).
The typical list of symptoms is shown above.
In addition, if the condition is extreme, malnutrition due to malabsorption might occur. Some cases of childhood Failure to Thrive appear to be associated with severe cases of fructose malabsorption, but these may also have comorbidities (other problems at the same time) or other underlying conditions. So far, clinical studies do not tend to line up with FTT being a typical direct result of Fructose Malabsorption (though the combination of FM and lactose intolerance does tend to create growth problems, and there is clinical evidence that excess apple juice consumption results in overweight low stature children. Apple juice overconsumption mimics FM.). Individual cases have found growth rebound with an appropriate diet for Fructose Malabsorption, or with use of probiotic therapy, or both. If there is FTT, make sure to pursue both allergy (dairy, wheat, especially) and celiac disease testing, as both are more commonly associated with growth delays.
Will it ever get better?
Maybe. If you have an underlying condition that may be improved or repaired, then it can certainly get better. But better also has to do with where your natural capacity to absorb fructose falls - there's a range, and some people will just naturally be on the lower end of the range. If you're in that lower range, you are, and will remain there. There may be ways in the future of managing the symptoms in such as way as to give back the freedom to eat what we choose when we choose and how much we choose - but for now, it is dietary management, and handling the underlying condition (if any). Current research direction is toward changing gut biota (probiotic balance) but the complexity of creating an entire balanced gut environment is substantial, given that there can be 600 or more types of gut bacteria in a healthy individual. There are also enzymes that may help break down some of the other fermentable compounds, and even (in Europe) enzymes for breaking down fructose (converts to glucose, which results in an increase in blood sugar for some people, which also may cause other problems). As research continues, the best approach is management.
What is a Polyol and why do I need to watch for them?
Polyols are a sugar alcohol - non-caloric, we don't break them down, digest them at all. They block fructose absorption. If ALL you ate for three days had zero fructose but did have polyols, you'd probably be okay. BUT. Since we do tend to consume some fructose (even if in balance with glucose), consuming polyols along with causes problems. This is why on sugar-free items there is often a note saying 'may cause diarrhea if consumed in excess' - because they'll turn a normal digestion into a Fructose Malabsorbing one just by being present. Hence the diarrhea. For people with FructMal, they should be avoided, but it isn't because we malabsorb them, rather because consuming them makes the malabsorption worse. So, they're still on the 'AVOID' list, just not because they somehow create fructose. They just make it even harder for us to absorb fructose. Instantly, just by being present in the gut.
What are Fructans?
Fructans are long chains of fructose molecules 'stuck together' with a glucose molecule at the end (called a 'polymerized fructose chain with a terminal glucose' in the technical terms). Short chains of these are called Inulin, prebiotics, and/or fructo-oligo-saccharides ('FOS' - basically long-chain-of-fructose-sugar). They're all fructans. They vary in chain length. Inulin is shorter chain lengths in particular. They're all very very good at feeding gut bacteria in the lower small intestine and beyond. This is because (if I have this right) it takes some time in the digestive process to start breaking off the fructose molecules from the chain. So as it goes down the tract, it bypasses where fructose is NORMALLY absorbed (upper small intestine), and then keeps going, breaking down further as it goes. This creates more fructose 'downstream' which then feeds the bacteria, and ta-DA! Happy bacteria. Only, with fructose malabsorption, we already have plenty of fructose that far down, and instead of just causing 'a slight boost to the food supply' for the bacteria, it becomes a huge feast, they go nuts, reproduce like mad (including ones we don't want), start dropping byproducts of metabolism to the gut and bloodstream (methane, hydrogen), plus producing plenty of gas that doesn't go to bloodstream, plus the whole fermentation process triggers the body to drop fluids through the lining of the intestine to balance the body ('osmotic diarrhea' - fluid from the bloodstream transports over to the GI tract, just like someone pumped water into your intestines)... and hello, symptoms! The issue with fructans seems to be that the shortest chain ones seem to break down the most, and soonest, so they have the biggest free fructose response in the intestines. And we've already GOT that, so it becomes way excess. Bad.
Why is yogurt a problem?
Fructans/inulin/prebiotics are added to many yogurts to 'support the benefits of the probiotics (bacteria cultures)' - essentially, they're saying 'we've included good bacteria, and to improve the benefits from them, we've sent along a care package of food for them, too'. Fine if you don't already overfeed your gut flora naturally. Not fine for those of us too good at doing that already.
Also, probiotics themselves may cause trouble for people with fermentation already ongoing in their intestines. Until we know more about which probiotic strains help, and which don't, proceed with caution.
Can I use probiotics separately?
The advice I've seen from the experts on Fructose Malabsorption is that for now, probiotics are not recommended. There is too much variability in the reactions, there's no good data supporting their use (especially as they're being used willy-nilly - in yogurt, in probiotic drinks, different strains, strains not controlled for, no structured dosing, possible overdosing, no targeting for underlying conditions, etc.), and for many many people with FM, increasing the probiotic load = catastrophic reactions.
Advising the use of probiotics for people with FM would be like saying 'take antibiotics' for all fevers. Not even specifying WHICH antibiotics, just 'some' - and not how much, how often, or for how long. The medical standard begins with 'cause no harm', so proceeding with suggestion to use probiotics would be unethical. There may BE harm for some people, in some conditions (or many), with different underlying conditions, with various strains of probiotics.
This does not mean you must avoid finding a probiotic that works for you. It means that it is most advisable to talk to your care provider about what your underlying condition is (if any), and whether any probiotics may help. (In one case, both Culturelle and the Metagenics Lactobacilus plantarum 299v seem to help, but dosing has to be adjusted individually - the former helps with lactose digestion, which may help some specific individuals, and the latter is for reducing IBS-related fermentation symptoms in the lower small intestine. These should be discussed with the care provider, as misuse of probiotics could cause greater trouble.)
Anecdotally, probiotic therapy tends to make things worse for about two weeks before the new probiotic strain integrates into the gut ecology. That can be really challenging if things are already bad. Very slow small dose introduction has worked for some people. Also, results may not be visible for 5-6 weeks (it takes a while to get the colony stable), so it is easy to stop too soon, as well. This approach can be expensive, and disappointing if it doesn't help.
What about enzymes?
Some people are finding good results with taking broad spectrum enzymes (like Digest Gold from Enzymedica). Dosing may need to be fine tuned for individuals, and the benefit is also highly variable, with some people getting amazing results, others getting no notable difference.
Comments (2)
Christina Bradford said
at 8:31 pm on Apr 4, 2010
What can be done to help with Small bowel bacterial overgrowth?
hedra said
at 7:14 am on Apr 5, 2010
SBBO Small Bowel Bacterial Overgrowth can be treated medically - usually with antibiotics, antibiotics plus antifungals, antifungals alone, or any of those combined with probiotic therapy. Plus diet, for some. For people who are physically sturdy (and fully grown), some will do fasting to starve off the overgrowth, but this can be pretty hard on even an adult. Diet change can also help - unfortunately what works for SBBO is often not what works for FM. A lot of the people I know who have had SBBO only found long-term relief after doing a long run of antibiotics or antifungals, plus diet changes to help keep it down while their bodies rebalanced. There are also many alternative treatments, though you will need to research those carefully and if possible find a reputable practitioner to guide you through the process. It is easy to oversimplify the alternative therapies - in reality, doing them right is as potentially complex as taking an allopathic/western-medicine route.
SBBO is pretty common - I've been told by doctors that nearly everyone will have it at least once in their lives. Talk to a really good GI doc about management and treatment would be my first choice. Finding the really good ones is the harder part of that. If you have a child with FM, a major pediatric hospital like CHOP is worth the effort.
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