Fructose is a simple single sugar in the carbohydrate family. It’s found in fruits; root vegetables, such as beets, sweet potatoes, parsnips, and onions; honey; cane sugar; and high fructose corn syrup. Fructose actually requires less digestion than white sugar (sucrose), which is a double sugar with equal parts of glucose and fructose.
Is fructose healthier than sugar? Many people mistakenly believe that fructose is a healthier sugar because one of its sources is fruit. The fact that it’s used in many so-called “natural” foods also makes it seem benign. Although fructose is naturally present in fruit, the fructose that’s added to many commercially prepared foods is even more refined than plain white sugar.
Hereditary fructose intolerance is a genetic disease caused by lack of a particular enzyme that breaks down fructose. It’s a rare condition that only occurs in about 1 in 10,000 people. In terms of fructose as an IBS trigger, fructose malabsorption is commonly referred to as fructose intolerance, which occurs when absorptive cells in the intestinal lining don’t accept and transport fructose into the bloodstream.
The intestinal contents become supersaturated with fructose, causing gas and bloating and providing food for intestinal bacteria and yeast.
Fructose and IBS
Fructose, just like its cousin, sucrose (table sugar), feeds intestinal bacteria and yeast and can cause an imbalance in the number of organisms in the intestines.
Fructose from fresh fruit (sometimes referred to as fruit sugar) has the same effect as fructose sweeteners, but fruit can have the added effect of irritation due to the insoluble fiber in the skin of the fruit. But remember, fruit isn’t just empty sugar — it also has the added benefit of vitamins, minerals, and fiber. The goal here isn’t to get you to eliminate all fruit; you should be able to identify whatever culprit is triggering your IBS.
Prunes are well known and applauded for their laxative effect. In the last generation, prunes were a staple in many households. Because of their laxative capabilities, prunes have suffered from a lot of negative publicity; now, they’re often referred to as dried plums as a way to wipe the slate clean of the negative connotations of the word prune.
In addition to prunes/plums, when eaten in considerable quantities, peaches, figs, kiwi, pineapple, mango, and papaya have a laxative effect in most people. However, for someone with gut sensitivity, it may not take much to cause irritation and increased bowel movements.
Eat fructose-free
Products containing added fructose number in the thousands but can be identified by closely reading labels. Most of the fructose you encounter in foods is in the form of high-fructose corn syrup (HFCS) or crystalline fructose, which have nearly eclipsed sugar as the most consumed sweeteners in the U.S. HFCS contains 55 percent fructose and 45 percent glucose. Crystalline fructose is created by enriching corn syrup with fructose, making it 98 percent fructose.
In the past decade, researchers woke up to the fact that HFCS causes an elevation in blood lipids and should be avoided. The American Diabetic Association (ADA) used to include food products containing fructose in its recommendations because fructose is absorbed more slowly into the bloodstream than table sugar. Now, however, the ADA warns diabetics to avoid HFCS because of lipid elevation.
Eating or drinking 20 to 40 teaspoons of HFCS a day can overwhelm the body’s ability to digest it so that it stays in the blood and elevates the blood sugar.
That sounds like a lot of sugar, but when you realize that one can of soda contains about 10 teaspoons of sugar and that many people drink soda more than water, it’s not hard to down the equivalent of a cup of sugar (48 teaspoons) a day.
Take the fructose challenge
For a two-week period, avoid all fruit and fructose-containing products. If you’ve determined that dairy and/or gluten are not an IBS challenge for you, you may choose to continue to eat them during your fructose challenge.
Of course, if you reacted to foods from those avoidance experiments, keep them out of your diet, too. There’s no substitute for a piece of fruit, but you can use stevia, Just Like Sugar, and maybe some honey, maple syrup, or a dash of xylitol instead of fructose as a sweetener.
Keep a diary of your symptoms before and during the challenge, and see if they improve during the two weeks you’re fructose-free. When the two weeks is up and you challenge fruit, choose one that you would normally eat — don’t pick a new exotic fruit you’ve never tried before.
You want to measure your reaction to your typical foods, so this isn’t the time to try out new things. Eat several pieces of fruit and see how your body reacts. If that goes well and you don’t have symptoms, try a bottle of fruit juice sweetened with HFCS and assess your reaction.
Make sure that you write down all the symptoms that you notice — even if they aren’t IBS-related. You might discover an actual food allergy or other intolerance!
