Isomalt is a sugar alcohol (polyol) derived from the hydrogenation of isomaltulose, which is produced from beet sugar. This white, crystalline substance is a common sugar substitute in products like sugar-free hard candies, chewing gum, and baked goods. Individuals managing blood sugar levels often use Isomalt as an alternative to traditional sugar. The primary interest lies in its metabolic effect, specifically whether it causes a rise in blood glucose.
The Glycemic Impact
Isomalt has a minimal effect on blood glucose levels, meaning it does not cause a rapid or substantial spike in blood sugar. This negligible impact makes it suitable for sugar-free products marketed toward individuals with diabetes. Isomalt is classified as having a very low glycemic index (GI), which measures how quickly a food raises blood sugar.
The glycemic index for Isomalt is typically reported to be around 2 to 9, significantly lower than the GI of table sugar (sucrose), which is 65. A low GI indicates that the carbohydrate is absorbed slowly and gradually, requiring only a minimal insulin response. Although it is not a zero-calorie substance, its structure ensures that the caloric and glucose impact is greatly reduced compared to regular sugar.
How Isomalt is Processed by the Body
The mechanism behind Isomalt’s low glycemic effect is its resistance to complete digestion in the small intestine. Isomalt is a disaccharide alcohol, and digestive enzymes struggle to break down its stable chemical bond. As a result, a large portion of the ingested Isomalt passes through the small intestine mostly undigested.
Since it is not fully broken down and absorbed, the body takes in fewer calories and less glucose from the substance. The undigested portion travels to the large intestine, where it is fermented by naturally occurring gut bacteria. This incomplete digestion and subsequent fermentation result in Isomalt having a reduced caloric value of about 2 calories per gram, half that of sucrose.
Potential Digestive Effects
Since a significant amount of Isomalt reaches the colon undigested, it can lead to certain non-metabolic side effects. The presence of undigested polyols in the large intestine draws water into the bowel through an osmotic effect. This increased water content, combined with fermentation by gut bacteria, can cause gastrointestinal discomfort.
Common side effects include increased flatulence and bloating due to gas production during bacterial fermentation. When consumed in large amounts, Isomalt can also lead to a mild laxative effect, resulting in softer stools or diarrhea. Daily doses of up to 50 grams are generally tolerated well by healthy adults, but individual tolerance varies, making moderation important.
Comparison to Table Sugar and Other Sweeteners
Isomalt is classified as a bulk sweetener because it provides volume and texture similar to table sugar (sucrose) in food products. Its sweetness level is only about 45 to 65% of sucrose, meaning it is not as intensely sweet as regular sugar. This lower sweetness profile often requires blending with high-intensity sweeteners, such as sucralose, to achieve comparable sweetness.
The caloric value of Isomalt is approximately 2 calories per gram, compared to 4 calories per gram found in sucrose. Unlike some other sugar alcohols, Isomalt does not have a pronounced cooling sensation in the mouth. Furthermore, its physical properties, including high resistance to crystallization and humidity, make it a preferred choice for manufacturing hard candies and decorative sugar art.