“Pregnant belly.” That was the most accurate way I could describe how my stomach used to look after eating. No more than a couple of hours after a meal, my abdomen would swell to more than twice its normal size, and the pain in my belly was intense. It often lasted for days, and despite all of my best efforts at tracking my diet I was unable to identify any one food trigger.
In fact, the foods I was eating seemed to have completely unpredictable effects. I could eat an apple and some whole grain cereal with milk for breakfast one day and have little to no trouble, and the next day the same foods would trigger the pain and bloating in full force. The only common denominator I could identify was food itself.
The less I ate, the better I felt, and so I started eating as little as possible in an effort at pain management. I often avoided social situations because of the unpredictability and the potential pressure to eat, and I was losing weight. Fast. At 5’5″ I went from 130 pounds to less than 110 in a relatively short time. It was clear to me that this was not a sustainable lifestyle. The rapid weight loss, combined with a trip to the emergency room one night with the worst pain I had experienced yet, led me to seek the help of GI specialist, Dr. Martin Hahn.
Dr. Hahn was instrumental in finding the source of my abdominal pain and bloating. He listened carefully to my history and symptoms and ruled out every disorder one by one: celiac disease, lactose intolerance, bacterial overgrowth, gastroparesis, gallbladder dysfunction, and the list went on. But after more than a year’s worth of testing, everything that might have caused my symptoms came back negative. Meanwhile I continued to lose weight. Another physician offered a second opinion: try antidepressants for the pain, since the cause of the pain was unknown. That wasn’t enough for me–I wanted to discover the source of the pain and not just mask it.
Fortunately Dr. Hahn did not give up on me. While we continued working together to rule out every functional cause as well as the most likely food allergies, Dr. Hahn encouraged me to do my own dietary research. After all, food seemed to be the only common factor in my symptoms. Not too much later I stumbled upon something I’d never heard of before: fructose malabsorption. Symptoms were consistent with my own, and the trigger foods were many of the foods I was eating. Could this be the answer to my digestive distress?
There were no reliable tests for fructose malabsorption at that time. Today some physicians advocate use of a hydrogen breath test, similar to the test for lactose intolerance, but the accuracy is still debated. Dr. Hahn encouraged me to try reducing the supposed trigger foods and see what happened. I took his advice, and took the first step on my personal path to a healthy diet and lifestyle.
Fructose is a simple sugar found naturally in fruits and sweeteners such as honey, and also in artificially high amounts in high fructose corn syrup. In normal individuals, fructose is absorbed in the small intestine, but in those with fructose malabsorption it is only partially absorbed. Any unabsorbed fructose travels on to the large intestine, where it is rapidly fermented by bacteria. The by-products of the fermentation cause varying degrees of gas, bloating, abdominal pain, constipation or diarrhea depending on the individual.
Fructose is generally well absorbed when there is an equal amount of glucose available at the same time. It seems that the transporters that facilitate fructose absorption in the gut may be up-regulated in the presence of glucose. That means free fructose can be safely consumed as long as it is balanced by an equal or greater amount of glucose. (This is not the case with hereditary fructose intolerance, a life-threatening condition in which no fructose may be consumed.)
For example, simple white table sugar (sucrose) is generally safe in moderation for individuals with fructose malabsorption because it contains equal proportions of glucose and fructose. Honey and high fructose corn syrup in contrast contain much more fructose than glucose per serving, so they are not safe. Supplemental glucose may be consumed to offset excess free fructose and facilitate absorption.
However, fructose is not always found in its free form. It also exists widely in the food supply in the form of fructans. Fructans are long chains of fructose with a glucose “tail” at the end. Humans don’t have the enzymes to digest fructans, but the bacteria in our large intestines do. The fructans pass straight through to the large intestine where bacteria digest them into fructose molecules. Although this is not technically malabsorption since the absorption area is bypassed altogether, it has the same effect, resulting in more substrate for bacterial fermentation. Fructans can be found in wheat, brown rice, garlic, onions, and many other common plant foods.
One of the biggest challenges of living with fructose malabsorption is food labeling. Many of the trigger foods are whole foods that are sold without packaging. Even if they were labeled, the necessary information would probably not be included. For example, a label on an apple might list total sugars and dietary fiber, but it would not tell the consumer that the apple contains more fructose than glucose, or that it contains sorbitol which compounds the effects of fructose malabsorption.
There are some lists available that detail the sugar ratios in various foods, but they often conflict. I chose to use the lists as a guide, taking them with a grain of salt. Between the lists and a healthy dose of trial and error, I have established some effective personalized eating guidelines for myself. My weight is stable, I can go out to restaurants or to friends’ homes for meals, and I no longer shirk all social events due to unpredictable stomach pain.
Fructose malabsorption can occur in anyone whose fructose intake outweighs his or her absorption capacity. It is different for everyone. The level that works for me may be too much for someone else. Some foods may be safe one day and not the next, depending on the overall fructose and fructans load from other foods consumed that day.
While no standard limit has been established, children generally have a much lower threshold than adults, and those with IBS may find their symptoms compounded by excess fructose since the symptoms are often similar. The general rules for those who experience fructose malabsorption symptoms are to minimize free fructose and avoid fructans.
Now instead of restricting food intake, I have been able to develop my own safe and healthy way of approaching food. Eating at home is always safest because I know reliably what goes into all of my meals. I translate nearly every recipe into my own special substitution language. “Wheat Berry Salad with Roasted Tomatoes and Asparagus” translates to “[safe grain] with [safe red vegetable] and [safe green vegetable].” This has made cooking and eating a much more creative (and less painful!) experience.
Living with fructose malabsorption remains a challenge at times, but I’m grateful for what I’ve learned from it. Home cooking and clean eating are valuable skills, plus I am much better able to identify with the growing community of people with food allergies and sensitivities. By sharing our common experiences we have the power to help each other and those around us achieve healthier and happier lives.
(C) 2013 Dawn Oulton