The Low-FODMAP Diet Cookbook (3 page)

The two main oligosaccharides that are FODMAPs are:

Fructans,
made up of fructose sugars joined together to make a chain (with glucose at the very end).

Galacto-oligosaccharides
(GOS), made up of galactose sugars joined together, with a fructose and glucose at the very end.

Di
means two, and
saccharide
means sugar. So these are two individual sugars, joined together to make a double sugar.

The important FODMAP disaccharide is lactose, made up of an individual glucose sugar joined to an individual galactose sugar.

Mono
means one, and
saccharide
means sugar. So these are individual sugars.

The important FODMAP monosaccharide is excess fructose. Not all fructose needs to be avoided. Only foods that contain more fructose than glucose (or “excess fructose” foods) need to be avoided on the low-FODMAP diet.

If a food contains more glucose than fructose, or if glucose and fructose are present in equal (“balanced”) amounts, then it is suitable on the low-FODMAP diet.

If a food (for example, a piece of fruit) contains more glucose than fructose, or equal amounts of fructose and glucose, it is suitable to eat; however, only one piece of suitable fruit should be consumed at a time. This doesn't mean you can only have one piece of fruit per day! You can have several, but spread them out so that you only have one per sitting.

A polyol is made up of a sugar molecule with an alcohol side-chain. Polyols are also known as sugar alcohols, but I promise they won't make you feel intoxicated!

The two polyols most commonly occurring in foods are sorbitol and mannitol.

Though all FODMAPs may trigger symptoms of IBS, there are breath hydrogen (or methane) tests available to determine individual sensitivity to certain sugars, especially fructose, lactose, and sorbitol. Breath tests are not a prerequisite for following the low-FODMAP diet but can be helpful in planning it. Ask your doctor if you are interested in having these tests run.

The tests work on the basis that bacteria in the large intestine produce hydrogen and/or methane gas by fermenting carbohydrates. Although some of the gas produced in the large intestine is passed out as flatulence, most of it is transferred across the lining of the large intestine into the bloodstream. The gases then dissolve into the blood, and the blood carries it to the lungs, where it is breathed out and can be measured.

Different testing centers have different guidelines for breath tests; however, you generally need to follow a low-FODMAP diet the day before the test to ensure that there is no hydrogen or methane already in your breath on the day of your test. A sample of your breath is collected into a special airtight bag and is then tested for the presence of hydrogen and/or methane, measured in parts per million. This is considered your baseline breath test. You then drink a solution containing a specific sugar (e.g., fructose, lactose, or sorbitol). Only one sugar can be tested at a time, and each sugar must be tested on a different day within the span of a month. Once you have drunk the solution, you breathe into a new airtight bag at regular intervals over a period of around three hours. Each testing center has different criteria for defining malabsorption of sugars tested. It is also helpful to keep a record of any symptoms you experienced at the time of the test.