IBS--Free at Last!

Polyols 101

Many of my clients tell me that even a few small pieces of sugar-free candy or gum cause diarrhea. Ditto for the well-know effect of prunes or cherries. What do these foods have in common? They contain polyols, also known as "sugar alcohols".

Technically, they are FODMAPS carbohydrates, and they are sweet! Most polyols are poorly absorbed, and wind up in the large intestine when they are consumed. In the large intestine, polyols are fermented by gut bacteria. They are also capable of drawing water into the large intestine. Together, the excess gas and excess fluid can cause distension of the colon, which cause bloating, flatulence and looser stools for the IBS sufferer. In a double whammy, eating or drinking sugar alcohols worsens fructose intolerance!

Some sugar alcohols, such as sorbitol, occur naturally in fruits such as apples, pears, and the "stone fruits," which include plums, prunes, apricots, peaches, cherries and so on. Sugar alcohols are often used to sweeten "sugar-free" foods (such as candy, gum, low-carb items, and bubbly water) and liquid medications. They can be recognized on the food label's list of ingredients by the ending "-ol". Examples are xylitol and maltitol.

Note that erythritol seems to be an exception. Studies have shown it is well absorbed and unlikely to cause GI symptoms.

Which Tomato Products are FODMAPS-Friendly?

Fresh tomatoes contain fructose in very small amounts. They are FODMAPS-friendly. However, when tomatoes are processed into tomato paste, the fructose is concentrated a great deal. According to one of my favorite references, Cook's Thesaurus, just 1tablespoon of tomato paste is equivalent to 1 medium tomato! So tomato paste is NOT allowed during the elimination phase of a FODMAPS-elimination diet. Depending where you are in the world, tomato paste may be called tomato puree or tomato concentrate, so check food labels for all these terms.

Check the nutrition facts on the label to see how the product compares to fresh tomatoes (2 grams sugar per 1/2 cup) versus tomato paste (16 grams sugar per 1/2 cup). This tip assumes the product has no sugar added as an ingredient, and that the sugar listed on the nutrition facts panel is all coming from the natural sugars in the tomato.

After reading the label, if you're still not sure whether the tomato product you have is OK to eat during the elimination phase, you may have to open the can and look inside. Whole canned tomatoes or diced canned tomatoes with watery-looking juice in the can are OK to eat during the elimination phase of the diet. if the juice in the can is thicker than water, transfer the contents to a a freezer-safe container, stash in the freezer, and wait until the fructose challenge phase to eat this tomato product.

Fructose 101

Fructose is known as "fruit sugar". It is present in fruits, some vegetables, honey, granulated sugar, agave syrup and high-fructose corn syrup. In the past, the human diet was lower in fructose than it is today--think of how hard it was to get honey in the wild, for example, or what a treat it would have been in the past to have fruit out of season, much less a never-ending supply of ketchup, cookies, candy and other sweets. Now it seems as though fructose is everywhere in our food supply.

Our capacity to absorb fructose is easily overwhelmed; it is almost considered normal to experience abdominal pain, flatulence, bloating or diarrhea when we overdo the amount of fruit or fruit juice we consume--many people have experienced this phenomenon. But some of us experience symptoms with much smaller intakes of fructose. And most of us overlook the impact that large portions of sugary sweets, baked goods and soft drinks can have. And what about those honey or fruit juice concentrate-sweetened energy bars? Interestingly, apples are part of the traditional BRAT diet sometimes recommended to fight diarrhea. Umm...maybe apples and apple juice aren't such a good idea for some people with diarrhea.

Diagnostic dietary fructose intolerance tests are available, but are not ordered as frequently in the US as they are elsewhere. If you suspect you don't tolerate fructose very well, try cutting back on soft drink and other sweets. Limit tomato paste. Choose small portions of fruits that are lower in fructose, such as kiwi, berries, citrus fruits, and bananas. Read labels, and avoid or limit portion sizes of foods sweetened with honey, fructose, high-fructose corn syrup, agave syrup and fruit juice concentrates.  See if you feel better!

Fructose malabsorption can occur on its own, or it can be part of the larger IBS picture.The FODMAPS elimination diet in IBS--Free at Last! can help you figure out how fructose fits into your IBS scenario.

It is important to distinguish dietary fructose intolerance, described in this posting, from hereditary fructose intolerance, which is a serious, hereditary disorder requiring a truly fructose-free diet.

Click here for more details about dietary fructose intolerance and how it causes GI symptoms.

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Great news for avocado lovers!

Creamy, ripe avocados are one of my favorite foods! I know I'm not alone here. One of the top questions from newcomers to the FODMAPS elimination diet is, "Can I still eat avocados?" This is a fair question to ask, since avocados have rather more fiber in them than one might guess: almost 7 grams in half of an average avocado. To put this in perspective, this is approximately the same amount of fiber contained in 1/2 cup of kidney beans!

Luckily, the type of fiber in avocados is not unfavorable. Avocados have an almost undetectable amount of fructans in them. Fructans are a type of fiber found in wheat, onions, and certain other plant foods. Fructans are not digested or absorbed by humans--that's part of what defines them as dietary fiber. When they hit the colon (large intestine), they are highly fermentable by gut bacteria, and can cause painful gas and bloating in some individuals with IBS. In other good news, avocados contain far less free fructose than other vegetables, so are unlikely to cause symptoms for individuals with dietary fructose intolerance.

All in all, it looks like avocados can be added to the list of foods allowed on the elimination phase of the diet described in IBS--Free at Last! Check out my recipe for FODMAPS-friendly guacamole, and enjoy!

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Fructose Malabsorption and Fructose:Glucose Ratio

What's up with the fructose:glucose ratio? If I experience dietary fructose intolerance, why can I tolerate fructose better if there is an equal amount of fructose in the meal?

First, let's recall the context here: the goal is to manage gastrointestinal symptoms, not to eliminate fructose, per se, from the diet. That's just not necessary (unless one has hereditary fructose intolerance, another subject entirely). Next, recall that high fructose foods include many fruits, honey, and sweetening ingredients such as high fructose corn syrup, crystalline fructose, and fruit juice concentrates.

The ability of the small intestine to absorb fructose is limited, at best. This was less of a problem years ago, when our intake of fructose was also limited! As recently as 30 years ago, the average U.S. intake of fructose was only 2/3 of what is is today, due to changes in the food supply. Imagine the distant past, when honey would have been a rare sweet treat, requiring feats of courage and strength to obtain. Cane or beet sugar and a wide variety of fruits would not have been available to most people in the world, except on rare occasions. Now, our diets contain lots of fructose, although over half of us can't fully absorb a 50 gram serving of fructose. Any time you are eating fructose faster than your personal ability to absorb it, the unabsorbed fructose will be carried on into the large intestine, where it is fermented by the resident bacteria, causing gas, bloating and altered bowel habits.

It appears there are probably two way fructose is absorbed through the cell walls of the small intestine. The first way is a low-capacity type of diffusion, in which a fructose molecule can pass through the cell wall on its own. The second mechanism is transport system that only works when there is one glucose molecule available for every fructose molecule. If there is no glucose-fructose pair, there is no absorption.

This explains why granulated sugar, which contains an equal amount of glucose and fructose is well tolerated in moderation, even by fructose intolerant individuals. Also, fruits such as berries, certain melons, and citrus fruits, which do not have an excess of fructose compared to glucose, can be tolerated in small servings. The fructose intolerant individual could still experience symptoms if very large portions of these "allowed" foods or beverages are consumed.

If you learn that you have dietary fructose intolerance, but would still like to consume high fructose foods, you might be able to do so if  you take a glucose/dextrose tablet along with the food, to improve the fructose:glucose ratio. These inexpensive tablets are sold at your local pharmacy along with diabetic supplies.

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