Fructose, the sweetest of sugars, is a simple carbohydrate also known as fruit sugar or levulose. Although fructose has the same chemical formula as glucose or blood sugar, its structure differs in a way that stimulates the taste buds and produces the sweet sensation. When fructose is linked together with glucose it forms sucrose, commonly known as table sugar, beet or cane sugar. Fructose occurs abundantly in fruits, honey and sap, the fluid that carries nutrients throughout a plant. The sweetness that fructose imparts to fruit attracts people to this nutritious part of a healthful diet.
According to Sareen Gropper, Jack Smith and James Groff in the text “Advanced Nutrition and Human Metabolism,” more than half of adults have a limited ability to absorb fructose which results in intestinal problems when high levels of this sugar are consumed. If glucose is present, the fructose, which is metabolized in the liver, absorbs faster and with less difficulty.
High Fructose Corn Syrup
High fructose corn syrup, or HFCS, is manufactured by using enzymes to change the glucose in cornstarch to fructose. Because HFCS is inexpensive and intensely sweet, it is often used in processed foods. Sources include soft drinks, ready-to-eat cereals and desserts sweetened with high-fructose corn syrup. It is added to canned and frozen fruits to preserve the natural color, flavor and structure of the fruit. It is added to soft drinks to add body without masking flavor.
According to Ellyn Satter, internationally recognized authority on child feeding, limit fruit juice to 4 ounces per day for infants. Infants and children with diarrhea should not be given fruit juices such as apple, peach and pear that have high fructose content because many infants and children poorly digest and incompletely absorb fructose. It then attracts water and bacteria in the large intestine and can cause gas and irritation as well as make stools more liquid.
Two metabolic disorders involving fructose respond to dietary treatment. A rare hereditary fructose intolerance as well as a rare enzyme deficiency both result in the inability to tolerate fructose according to Kathleen Mahan and Sylvia Escott-Stump in the text “Food, Nutrition, & Diet Therapy.” Treatment includes a diet that has no fructose, sucrose or the sugar alcohol sorbitol.
Current research yields conflicting results about the effects of high-fructose corn syrup and whether an association exists between consumption of beverages sweetened with HFCS and obesity. Consumers should use moderation while research continues. Persons concerned about the amount of HFCS or other sweeteners in the diet could take the following actions: limit processed foods, avoid foods with added sugars and limit consumption of soda.