Fructans vs Gluten
The official fructans definition is “a type of polymer of fructose molecules found in certain fruits.” Putting aside the scientific jargon, though, fructans are simply a type of carbohydrate made by a chain of fructose molecules strung together.
Fructans can be found in many types of fruits and vegetables, such as onions, artichokes, garlic and ripe bananas, as well as several different kinds of cereal and grains. Food manufacturers also sometimes add fructans to foods to increase the fiber content of their products. Because humans don’t have the fructan digestive enzyme, fructans cannot be effectively digested in the small intestine like other nutrients. Instead, they are fermented by the beneficial bacteria in your gut.
What Are Fructans?
There have been a number of health benefits associated with soluble sources of fiber like fructans. A high intake of fiber may help protect against conditions like coronary heart disease, high blood pressure, diabetes, obesity and even some gastrointestinal disorders. Fiber can also help promote regularity and prevent constipation, plus support satiety and keep your appetite under control to aid in weight loss. Not only that, but it also helps improve the health of your gut microbiome, which is associated with everything from enhanced immunity to reduced inflammation.
However, despite the impressive array of health benefits attributed to fiber, certain types of fiber like fructans may have an adverse effect on health as well. In fact, although some people may tolerate fructan-frich foods just fine, they can trigger some serious gastrointestinal issues in others. Bloating, diarrhea, pain and constipation can be common symptoms of an intolerance to fructans.
Fructans and galactans are long carbohydrate chains of about 3 to 9 carbohydrate molecules. Fructans are also called fructooligosaccharides (FOS) and gallactans galactooligosaccharides (GOS). Oligosaccharides belong to the non-digestible carbohydrates. These carbohydrates cannot be broken down in the small intestine and leave the body through the large intestine. In the colon, these undigested carbohydrates are fermented, releasing gas and attracting fluid, among other things.
No one can digest fructans and galactans properly, the difference is in the amount of symptoms you get as a result of the fermentation process. Our focus here is on fructan or galactan intolerance when someone suffers greatly from the fermentation process. It can differ from person to person whether someone only reacts to fructans or galactans, or to both types of oligosaccharides.
Note that fructan intolerance is not the same as fructose malabsorption or a fructose “allergy.” This is caused by a reaction to the units that make up fructans, which are a form of simple sugars known as fructose. Although they can cause similar symptoms, the main difference between fructan vs. fructose is that fructose is found primarily in fruits, fruit juices, agave nectar, honey, molasses, table sugar and high fructose corn syrup, while fructans are found in certain types of grains, vegetables and processed foods.
It’s also important to remember that a sensitivity to fructans is not the same as small bacterial overgrowth, or SIBO. This is a condition characterized by an excessive amount of bacteria in the small intestine, which can cause issues like diarrhea and malabsorption if left untreated. With a fructan intolerance, the main problem isn’t your gut bacteria, but the way that your body handles fructans.
Fructans vs. Gluten
While fructans are a type of carbohydrate, gluten is actually type of protein found in many cereal grains and wheat products. For those with celiac disease or a sensitivity gluten, eating gluten can cause a slew of negative gluten intolerance symptoms, such as diarrhea, fatigue, gas and even bone loss.
Sometimes there is some confusion about the difference between fructans and gluten. Many people think they are reacting to gluten after eating bread or other grain products, however, they could, in fact, be reacting to fructans. Grain products made from wheat often contain high levels of fructans as well. A gluten-free diet can help because it reduces your intake of fructans.
A gluten allergy, also known as gluten intolerance or celiac disease, is another type of disorder. Due to a reaction of the immune system, the intestinal wall can be damaged after eating products containing gluten. However, if a celiac test comes back negative, then there is a good chance that it is a fructan intolerance.
In the case of fructans intolerance, there is no immune system reaction and no damage to the intestinal wall. Fructans are found in many other products, such as fruits and vegetables, in addition to cereal products. However, emerging new research has recently found that many gluten sensitivity symptoms may actually be caused by impaired fructans digestion instead. This is because fructans are also found in many gluten foods and can cause symptoms that are similar to those triggered by a gluten allergy.
Gluten sensitivity, in particular, is a condition that is especially difficult to officially diagnose. Many people with a sensitivity to gluten find that they feel better when cutting out gluten-containing foods from their diets, but it’s unclear if this may be due to the elimination of gluten or a reduced intake of other ingredients, such as fructans.
Interestingly, a recent 2018 study published in the journal Gastroenterology looked at 59 people without celiac disease who were following a gluten-free diet. They were randomly assigned to receive a bar containing either gluten, fructans or a placebo for seven days before switching groups. At the end of the study, they actually found that consuming fructans resulted in more symptoms of irritable bowel syndrome, such as gas, bloating, abdominal pain and bowel changes, than gluten, indicating that cutting back on fructans may be the key to gastrointestinal relief for those with a gluten sensitivity.
Signs of Fructan Intolerance
The causes of fructan intolerance are not well understood. Some people seem to have less capacity than others to digest and absorb fructans into their bloodstream, and others experience stronger symptoms than others as a result of the fermenting of the unabsorbed sugars.
If you experience such symptoms on a regular basis, it is a good idea to discuss them with a doctor. Diagnosis of fructan intolerance is still in its infancy, but, as with other intolerances of sugars such as fructose intolerance, breath tests can sometimes be used to measure the content of gases that are produced when fructans are fermented in the gut, but the results are no guarantee of a correct diagnosis.
Properly identifying your symptoms can also aid in diagnosis. An intolerance to fructans can cause many symptoms, which may include:
Gas
Bloating
Stomach pain
Constipation
Diarrhea
Abdominal discomfort
Nausea
Cramps
If you suffer from these symptoms, reducing your intake of fructans. Trying out a fructan elimination diet can also help determine if you may have a sensitivity to foods high in fructans.
High-Fructan Foods to Avoid
Switching up your diet is the best fructan intolerance remedy. By eliminating fructans foods from your diet, you can start to sidestep unpleasant gastrointestinal symptoms and help find relief.
Use this fructans list as a guide for which foods you should limit if you have an intolerance to fructans. A few of the most common high-fructan foods include:
Breads/Grains: Barley, Rye, Wheat, Spelt.
Vegetables: Artichokes, Brussels Sprouts, Cabbage, Fennel, Garlic, Leeks, Onions, Peas, Shallots, Asparagus
Fruits: Grapefruit, Nectarines, Persimmon Fruit, Ripe Bananas, Watermelon, White Peaches
Nuts/Seeds: Almonds, Cashews, Pistachios
Legumes: Chickpeas, Lentils, Beans, Soybeans
Other: Instant Coffee, Chicory Coffee, Chamomile Tea, Foods containing inulin
Tips on how to manage fructan intolerance
If you suspect you may have a fructan intolerance, you should consult with a gastroenterologist and/or dietitian. There is a couple of options to help address and manage your symptoms.
Enzyme therapy: utilising a digestive enzyme called Alpha Galactosidase, this enzyme aids in the digestion of complex carbohydrates found in grains, legumes, and cruciferous vegetables. Reducing such symptoms as gas, bloating, indigestion, and diarrhea associated with fructans and galactans intolerance. Just remember, everything in moderation is the key when taking digestive enzymes, its not a green light to eat your body weight in onions and garlic.
Elimination Diet: A medical professional may design an exclusion diet in which you avoid food containing fructans for a limited period to see whether the symptoms go away. After the initial elimination of fructans, you should gradually add fructan-containing foods back into your diet one at a time to determine your individual intolerance. You should keep a diet and symptoms diary so that you can analyse the results obtained from eating different foods.
The low-FODMAP diet approach developed by Melbourne’s Monash University works in the same way. The idea is not to eliminate all FODMAPs from the diet forever, but ascertain the impact of each one and find a comfortable intake level as part of a balanced diet.
Before undertaking major changes to your diet, it is important to seek advice from your doctor and/or a dietitian to ensure that you are always eating a diet that is right for your nutritional needs.
