Guidelines for Effective Dietary Management of Fructose Malabsorption: The Low FODMAP Diet

Sensitivity to sugars like lactose, fructose and sorbitol are largely undiagnosed, but responsible for stomach bloating and intestinal distress to many. A group of indigestible carbohydrates or sugars, including oligosaccharides, disaccharides, monosaccharides and polyols have been shown to be osmotically active, rapidly fermenting in the gastrointestinal tract. Various studies show that these sugars are considerable triggers of gastrointestinal symptoms in patients with fructose malabsorption and IBS individually or in combination.

The low FODMAP diet has dramatically improved the gastrointestinal health of many with fructose malabsorption and irritable bowel syndrome in clinical trials. FODMAPs represent the food types that are most prone to fermentation by the gut bacteria. Evidence suggests that reducing global intake of FODMAPs to manage functional gut symptoms provides symptom relief for about 75% of patients with FGDs such as irritable bowel syndrome. Functional gut symptoms vary from person to person. The treatment of functional gut disorders varies. Modification of meal size, alcohol, fat and caffeine plays a crucial role. Consumption of adequate amounts of fiber and plenty of fresh pure water often helps dramatically in controlling and maintaining healthy digestive health. Recognition of the side effects that go along with supplements and medications is a must. Lifestyle changes that benefit digestion including relaxation, exercise, proper sleep and sunlight are also important key elements in addition to administering the Low FODMAP diet.

This group of poorly absorbed, short-chain carbohydrates, known as the FODMAPs was developed by researchers from Australia, Dr Sue Shepherd and Professor Peter Gibson. They coined the term FODMAPs as a way to categorize an otherwise unrelated group of certain types of carbohydrates. The acronym FODMAPs stands for Fermentable Oligosaccharides, Disaccharides and Monosaccharides. It is used to define an otherwise unrelated group of short chain carbohydrate and sugar alcohols. The FODMAPs are fermented by the bacteria of the intestines leading to flatulence, pain, bloating, reflux, diarrhea and constipation.

By reduction of dietary FODMAPs it is evident that there is success in providing relief from these symptoms to the majority of individuals with fructose malabsorption and relief to some with irritable bowel syndrome. Fructose is only one of the many poorly absorbed, short-chain carbohydrates that cause the symptoms of fructose malabsorption. These are complex names for a collection of molecules found in food that are poorly absorbed by some people. When these molecules are poorly absorbed in the small intestine, they act as a food source to the bacteria in the digestive tract, causing high osmotic activity and rapid fermentation which then leads to luminal distension and the potential for subsequent symptom induction in those with less adaptable bowels or visceral hypersensitivity.

In the individual fermenting short-chain carbohydrates like fructose and lactose may be malabsorbed, polyols are generally poorly absorbed and fructans and galactans are always poorly absorbed in all individuals. Consuming foods high in FODMAPs results in increased volume of liquid and gas in the small and large intestine, resulting in distention and symptoms such as abdominal pain and gas and bloating.

Those with fructose malabsoption show great improvement by being on the Low FODMAP diet. Many people experience a greater quality of life from being on this diet. This diet does require several dietary changes. Before starting, you should consult a registered nutritionist or dietitian to help ensure you are getting the appropriate nutrition including fiber. It is also important and relevant to understand that FM can co-exist with intolerance to other food chemicals including additives, salicylates, amines, lactose or gluten so it is important to pay attention to these if you still are experiencing symptoms when following the diet. Studies are still being conducted (currently at Monash University in Australia) on foods within the FODMAP diet. This diet is still in its infancy. New research will be revealed as time moves forward and more testing is done.

It is up to the patient to find there own personal tolerance level to specific foods, if they can tolerate them at all. The Low FODMAP diet acts as a guide to do just that. Until now there has been no such guide. Until now fructose malabsorption patients and IBS patients have been somewhat blindly learning what they can eat and what they cannot. Most foods do not have an immediate effect on the patient, meaning the symptoms may not show up until days later. It can be very difficult to know what is actually causing your symptoms. Symptoms can begin days later and end days later. The cycle consistently overriding itself means that patients can always be experiencing symptoms. The accumulative effect that the FODMAPs have and also the chemistry between them is a critical factor. You are a walking science lab. It will take some time to figure out your own personal meal plan. Many see improvement within the first week. Also you want to buy a notebook for a food journal. Record everything; every meal, every drink, any medications, anything consumed and of course the times. You also want to record your symptoms and those times as well too. This will help you identify a pattern.

The dietary advice for the reduction of fermentation of carbohydrates in the bowel is different for each person. By reducing the quantity of fermenting carbohydrates you will reduce symptoms. Small amounts of these carbohydrates will often be tolerated in some cases. In others total avoidance of a particular food, such as onions, is a must for symptoms to improve. It is important to understand that eating foods with varying FODMAP values at the same time will add up, resulting in symptoms that you might not experience if you ate the food in isolation. For example, fruits that contain excess fructose combined with naturally occurring polyols, such as apples and pears, will likely contribute to more severe symptoms, as the excess fructose and polyols content contributes to the total FODMAP load. The FODMAP’s: Fructose, Fructans, Lactose, Polyols (sorbitol & artificial sweeteners) and Galactans e.g. raffinose.

Fructose: This is a single sugar found often referred to as the “fruit sugar”. lt is in fruit, many vegetables along with many other foods. Fructose is a common additive in many commercial and processed products.

Lactose: This is a sugar that is in most milk and dairy products. As FODMAPs have a collective impact on GI symptoms, limiting lactose consumption is best. Hydrogen breath testing can be done. Many fructmals are lactose intolerant as it is the most common intolerance among the population. If you are unsure it is best to also avoid Lactose. Lactose intolerance contributes to abdominal bloating, pain, gas, and diarrhea, often occurring 30 minutes to two hours following the consumption of milk and milk products. Lactose intolerance is the inability to metabolize lactose, because of a lack of the required enzyme lactase in the digestive system. It is estimated that 75% of adults worldwide show some decrease in lactase activity during adulthood. Tolerance to lactose varies and dietary control of lactose intolerance is dependent upon unique tolerance levels. Lactose is present in two large food categories: conventional dairy products, and as a food additive (in dairy and non dairy products). Lactose (also present when labels state lactoserum, whey, milk solids, modified milk ingredients, etc.) is a commercial food additive used for its flavor, texture and adhesive qualities. It is found in foods such as processed meats.

Fructans: Fructans are long chains of fructose molecules ‘stuck together’ with a glucose molecule at the end (polymerized fructose chain with a terminal glucose). The main dietary sources of fructans include wheat and some vegetables such as onion. They may also be called inulin or Fructo-Oligosaccarides(FOS). Fructans are food for bacteria in the digestive tract. This causes the symptoms of fructose malabsorption and no amount of glucose will help to absorb these chains of fructose any easier. Fructans should be strictly limited.

Polyols: Polyols are also known as sugar alcohols. They have no calories and do not break down in the body or digest at all. Most are too large for simple diffusion from the small intestine, creating a laxative effect on the GI tract. These include sugar alcohols that are given names such as sorbitol,mannitol, maltitol, xylitot & isomalt. Excess consumption might have a laxative effect. If all you had to eat for three days was without any fructose at all you most likely would not experience any symptoms from polyols. This is however very difficult to do. Even fructose balanced with glucose will initiate the chemical reaction that polyols have within the body. Polyols also occur naturally in some fruits and vegetables. They are often used as an artificial sweetener and added as sweeteners to sugar-free gums, mints, cough drops, and medications. Polyols actually cause fructose malabsorption when digestion is normally healthy. In individuals who already have fructose malabsorption polyols cause FM symptoms to be much worse. This is because polyols make it even more difficult to absorb fructose. Limiting polyols or removing them all together is advised. Some fruits and vegetables with polyols can be consumed with an individual tolerance for different individuals. Avocados are one example. Apples, apricots, cherries, nectarines, pears, plums, prunes and mushrooms also have polyols.

Galactans: Galactans are oligosaccharides containing chains of the sugar galactose that end in a fructose and a glucose. The human body lacks the enzymes to hydrolyze them into digestible components, so they are completely contributing to gas and GI distress. Raffinose and stachyose are examples of galactans. These are found in legumes (baked beans, lentils, chickpeas) and some vegetables including peas and onions.

The Low FODMAP Diet: Dietary management of fructose malabsorption.

1. Avoidance of foods with high levels of free fructose and “short-chain fructans”.

2. Limited total fructose load.

3. Recommendation of foods with balanced fructose/glucose levels.

4. Intake of free glucose.

5. 8 – 10 weeks on the Low FODMAP diet. If improvement takes place begin to challenge separate components one at a time. Establish tolerance level that is personal to you. Remember that FODMAP’s have an accumulative effect in your body. It is suggested that you seek the guidance of a dietician to ensure you are getting the appropriate nutrition and fiber requirements.

High Fructose Foods: High fructose foods that have a higher fructose percentage than glucose percentage can cause many negative reactions to those with fructose malabsorption. They should be avoided or strictly limited. Consumption of free glucose will help absorb excess fructose but there is still a limit as to how much fructose the small intestine can handle. Fructose is generally only a problem when there is more fructose than glucose present or too much fructose is eaten at once, such as eating two or three pieces of fruit in one sitting. Some high fructose foods are:

  • Honey
  • Apples (all varieties)
  • Pears
  • Dried fruit
  • Fruit juice
  • Coconut in any form
  • Peaches
  • Honeydew melon
  • High fructose corn syrup
  • Watermelon
  • Star fruit
  • Lychee
  • Nashi fruit
  • Canned fruit
  • Corn syrup

Foods Containing Fructans:

  • Wheat (in large amounts) Unlike celiac disease trace amounts of wheat are okay and well tolerated usually with FM.
  • Rye (in large amounts)
  • Onions (all varieties) Onion is a MAJOR problem, even when eaten in small amounts.
  • Brown rice: Many report having difficulty with brown rice. It may be suitable in small amounts.
  • Leeks
  • Zucchini
  • Chicory
  • Inulin (artificial fiber added to foods etc. Check labels.)
  • Artichokes
  • Fructo-oligo saccharides (FOS) (artificial fiber added to some foods)
  • Dandelion tea

Foods Containing Sorbitol:

  • Artificially sweetened gum, candy and soft drinks
  • Artificial sweeteners: Sorbitol, Mannitol. Xylitol, Isomalt
  • Apples
  • Apricots
  • Peaches
  • Apricots
  • Nectarines
  • Pears
  • Cherries

Foods Containing Raffinose:

  • Cabbage
  • Brussel sprouts
  • Baked beans
  • Asparagus
  • Red kidney beans, Green beans
  • Legumes
  • Lentils
  • Chickpeas

Most dairy foods have lactose, some more than others. The following are on the higher end of the spectrum.

Foods Containing High Levels of Lactose:

  • Ice cream
  • Milk
  • Condensed milk
  • Soft cheeses

Closing Notes:

You can reach me at if you have any questions or concerns. I look forward to hearing from you.

Source by Maria Reine