Read about Low Fructose Diet:

1. Fructose, sorbitol, fructans, FODMAPs;
2. Amount of fructose, glucose, sorbitol and fructans in foods;
3. Low fructose diet principles;
4. Foods - safe, to try, and to avoid in fructose malabsorption.

You might also want to read about fructose malabsorption, Hereditary Fructose Intolerance (HFI), and FODMAP diet. 

Fructose

(What is fructose?)

Fructose is a simple sugar which naturally appears in honey, fruits, and many vegetables. It is a part of table sugar (sucrose), other sugars and syrups, including High Fructose Corn Syrup (HFCS). It doesn’t appear in animal foods. Even a healthy person usually cannot absorb more than 25-50g of fructose per serving. Persons with fructose malabsorption can absorb less than 25 g of fructose per serving.

One molecule of glucose enhances absorption of one molecule of fructose, so foods with fructose:glucose ratio 1 or lower are usually well tolerated if eaten in moderation.

On labels, fructose may be referred as fructose, or fruit sugar and it is a part of High Fructose Corn Syrup (HFCS), corn syrup solids, fruit juice concentrate, fructose-glucose syrup, corn sweeteners, honey, invert sugar, maple sugar, maple syrup, molasses, Turbinado.

Fructose Malabsorption

In this article, fructose malabsorption, formerly known as Dietary Fructose Intolerance (DFI), which is a common cause of diarrhea, is described. Another, rare, Hereditary Fructose Intolerance (HFI), which causes impairment of liver, kidneys and small intestine is much more severe. Fructose malabsorption and HFI are NOT allergies.

In fructose malabsorption fructose can’t be efficiantly absorbed from unknown reason. Transport protein GLUT5, responsible for fructose absorption in the small intestine, may not be present or becomes inactive. People with fructose malabsorption have fructose absorption limit lower than 25 grams per serving, but this may differ a lot from person to person. Fructose, unabsorbed in the small intestine, reaches the colon, where bacteria ferment it and yield short chain fatty acids, carbon dioxide (CO2), hydrogen and methane, which cause symptoms. It is estimated that about 1/3 of people are fructose intolerant, and about half of them have symptoms. People with fructose malabsorption may be also sensitive to other non-digestable carbohydrates, such as sorbitol and xylitol, raffinose (beans) and inulin (polyfructose), (5).

Who Can Get Fructose Intolerant?

Anyone at any time can develop fructose malabsorption. Abnormality or lack of GLUT-5, a fructose transporting protein, may be inherited (5). Other causes, suggested so far:

• family predisposition; 
• overuse of High Fructose Corn Syrup (HFCS), or fruit juices in children (toddler’s diarrhea); 
• small intestinal bacterial overgrowth (SIBO);
• celiac disease; 
• chemotherapy or radiation;
• dumping syndrome (rapid stomach emptying).