Fructose Malabsorption and Depression

Do an internet search for the terms "fructose malabsorption" and "depression" and you will find a lot of buzz over the possibility that the two are linked. Google returned over 6,800 hits on this combination. The idea seems to be taking on a life of its own, and is treated as fact on a number of web sites and blogs. I wondered if there was any of that pesky old evidence on the subject.

I've spent several evenings poking around the internet, reading abstracts and peer-reviewed research reports, most of them published in Europe. In fact there are a number of interesting published research reports that suggest there may be a link worthy of further study. It is far from proven, however. The handful of studies that have been done, most by a particular workgroup at the University of Innsbruck, Austria, included a very small number of study subjects. The researchers have tried to discover whether there was an association between fructose or lactose malabsorption and depression. They did find such an association, but only in females. But the studies simply weren't designed to prove that fructose malabsorption causes depression. It is intriguing, though, isn't it?

The researchers did some more small scale studies to explore possible mechanisms for the fructose or lactose malabsorption-depression link. They have discovered that there may be an association between fructose malabsorption and lower levels of tryptophan, zinc and folate in the blood. It is the job of scientists to speculate about how these observations could all fit together, and speculate they do. Could these nutrients be poorly absorbed because the fructose malabsorption causes diarrhea and reduces contact time between the contents of the GI tract and the absorptive surfaces of the small intestine? Could unabsorbed sugars be interfering with the absorption of tryptophan? Could fructose malabsorption be encouraging small intestinal bacterial overgrowth (SIBO)? Could the lower serum levels of tryptophan, zince and folate cause depression?

There are far more questions than answers, here. Scientists are choosing their words with care, using the terms "may" and "suggest" and "associated with," and they point out that further studies are needed.

What is the take-away message here for people with fructose and/or lactose malabsorption? If you're a woman, removing excess amounts of these sugars from your diet might make you feel better mentally as well as physically! That's all, folks.

The report that started it all? Fructose malabsorption is associated with early signs of mental depression, Ledochowski M, Sperner-Unterweger B, Widner B, Fuchs D. Eur J Med Res. 1998 Jun 17;3(6):295-8.

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Comments

[Linda Simon]

Thanks for your critical eye and keeping us up to date. There is so much we don't know yet.

[Julie]

Patsy-
REALLY interesting. It never ceases to amaze me how the body throws out signals that there are problems...and even more amazing, the research that goes into discovering these signals and what to do about them. Thanks for sharing!

[Linda Simon]

Patsy,
Thanks for your thoughtful and even handed review.

[Janice]

I discovered fructose malabsorption during the spring of 2009. I had already given up anything that was wheat related, but kept having abdominal pain. I tried going to dextrose (glucose), but since it is made from corn it has residual sulfites in it (and, of course, I have a sulfite sensitivity also). Went cold-turkey a few months ago, and don't use any type of sweetener, except that I can use milk products. My diet is quite simple, which makes shopping very very easy.

I eat steaks, ground buffalo meat (mostly because I've never heard of a recall of ground buffalo), green vegetables, potatoes, butter, and whole milk. I make a tea blend of peppermint, spearmint, and black tea, which I drink with half-and-half to give it the illusion of sweetness. I will sometimes cook up a little rice, but I have to be careful not to do that more than once a week. I also will sometimes grate up unsweetened chocolate, mix it with half-and-half, and nuke it.

Now, I have never been known as an even-tempered person. I fly off the handle easily, and always have. Been known to feel depressed at times, too. After being on a sugar free diet for two or three months, I turned to my beautiful husband, and asked him if he felt my behavior had improved. He said that I had become quite even-tempered, with mood swings that were very slight compared to what they had been previously.

In addition to that, though, my complexion has cleared up, hemorrhoids aren't acting up as much, abdomen does not hurt at all any more, and some persistent sores on my lips have disappeared.

I won't say it isn't hard to maintain this diet, because so many social activities involve food. But having lived with pain for most of my 57 years, I would say the decrease in pain is well worth it. I think my husband feels the decrease in mood swings is well worth it.

[Patsy Catsos]

Always interesting to hear how powerful diet change can be. Clearly,
you had some serious food sensitivities! The diet you have worked out
sounds very strict, but Im glad it is working for you, both physically
and emotionally. Perhaps eventually youll be able to liberalize it a
bit so you can enjoy a greater variety of foods. Time will tell.

[Patsy Catsos]

It makes me very happy to hear that you are feeling better! Thanks for letting me know. Its always good to know we are doing everything we can to help our health by managing our diet.

[sugar]

Fructose may lead to health problems, but both sugar & HFCS contain fructose in similar amounts

[Patsy Catsos]

Im glad you brought this up, as people are hearing a lot of this controversial message lately from ads on TV and elsewhere. On the face of it your statement is accurate, sugar and high fructose corn syrup (HFCS) contain similar amounts of fructose. But the devil is in the details.

First of all, I think we can agree that fructose is absorbed best in the presence of an equal amount of glucose, in other words when the sugars present in the food or beverage are 50% fructose and 50% glucose. During a FODMAPS elimination diet, it is foods with excess fructose that need to be avoided. Workers in the field define free fructose in excess of glucose as greater than .5 grams/100 grams of the food. So a food with 50.5% fructose and 49.5% glucose has enough fructose to be considered a potential problem.

Granulated sugar is always 50% fructose and 50% glucose.

According to the Corn Refiners Association (www.hfcsfacts.com), HFCS is sold principally in two formulations: 42% fructose and 55% fructose (90% fructose is less common). So yeah, HFCS is in the same ballbark in terms of fructose content--close, but no cigar. In fact, the 42% fructose version of HFCS, does not have excess free fructose and would be permitted during the elimination phase of the FODMAPS elimination diet. The 55% and 90% versions clearly have excess free fructose and are capable of causing symptoms for some individuals.

Since ingredient listings on food labels dont identify which form of HFCS is in a given food or beverage, my advice is to avoid it all during the elimination phase of the diet. Feel free to include any and all HFCS during the fructose challenge phase of your diet.

By the way, regular corn syrup is almost 100% glucose (dextrose), so it is allowed on a FODMAPS elimination diet.

[Michael Smoker]

Hi, Patsy. I wanted to email you but couldn't find the information. I note that the data on fructose intolerance and depression is from a study published in 1998. Is there any more recent research? Also, and of more interest to me, has there been any research specifically linking _lactose_ intolerance to depression? I've heard vague buzz about it but nothing definitive.

[Patsy Catsos]

There is a link to my email address on the bottom right of the blog, but I actually like it better when people contact my via comments, because then the conversation can benefit other blog readers as well.

I havent seen anything new published on the subject since a small 2005 study (JPGN 40:561–565, 2005) found an association of lactose and/or fructose intolerance with depression in adolescents. Its far from a firm cause-and-effect at this time; I would call the few studies that have been done intriguing leads to an area that needs much more study.  Ill watch for emerging information about this, and I invite readers to send me links to any published research I may have overlooked on the subject.

[Georg]

Dear Patsy. I have suffered from depression, anxiety and lots of other mental problems for most part of my life and I have problems with my digestion since the day I was born. I´m convinced that there is a conection between my diet and my mental issues but I still havent figured out what exactely it is.

I experienced symptomfree periods that lasted up to months maintaining a strict diet consisting of merely white rice and a few green vegetaples. The problem is that I always end up extremely underweight. maintaining this diet also restricts my social life and makes travelling nearly impossible.

How can I find out what kind of Intollerances I have? I live in Spain and here the doctors don´t even seem to know what a fructose malabsorption or fodmaps are. they usualy tell my I´m anorexic, give me some antidepressives and tell me to go for a walk in the sunshine.

maybe you know a way how I could get to the root of my diet problems.

[Patsy Catsos]

Hello Georg,

While I cannot give individualized advice in this kind of forum, I can say that the gastrointestinal disorder most related to mental health is celiac disease and non-celiac gluten sensitivity. Alternatively, when I hear about gut problems that go back to infancy was born it makes me wonder about inborn errors of metabolism such as galactosemia or hereditary fructose intolerance. A genetic specialist might be able to help. With regard to food sensitivities and intolerances, my knowledge of the scene in Europe is limited, but my impression is that a lot is going on in Italy--Dr. Alessio Fasans group at University of Salerno for example.

[Aurametrix]

Another article that showed association between carbohydrate (fructose and lactose) malabsorption and depression: Varea et al., 2005: http://journals.lww.com/jpgn/Fulltext/2005/05000/Malabsorption_of_Carbohydrates_and_Depression_in.6.aspx. Their study group was also small but included males.
Here is a blog on altered tryptophan metabolism and happiness: http://dysbiosis.blogspot.com/2011/05/tryptophan-in-food-will-it-make-you.html

[Patsy Catsos]

Thanks for sharing those links. Interesting.