The question of whether dextrin raises blood sugar is complex because “dextrin” is not a single substance but a group of carbohydrates derived from starch. These molecules result from the partial breakdown of starches from sources like corn, potato, or tapioca. The impact on blood glucose depends entirely on the degree of processing and the resulting chemical structure of the specific dextrin type. For individuals monitoring their glucose intake or managing conditions like diabetes, understanding this distinction is necessary for making informed dietary choices.
Dextrin Defined: Understanding the Different Types
Dextrins are low-molecular-weight carbohydrates created through the hydrolysis of starch, a process involving heat, acid, or enzymes. This partial breakdown yields shorter chains of D-glucose units. Depending on how the starch is processed, the resulting dextrin can be either highly digestible or largely resistant to digestion, leading to two distinct categories with very different metabolic effects.
The first category, exemplified by maltodextrin, is created to be easily broken down by human digestive enzymes. These dextrins are simple polymers of glucose that the body treats essentially like simple sugar. The second category, often called resistant dextrin, is chemically modified to resist digestion in the small intestine. This molecular change means the body cannot efficiently break down the bonds to release glucose into the bloodstream, causing it to behave like soluble dietary fiber.
Maltodextrin: The High Glycemic Impact Dextrin
Maltodextrin is a highly refined carbohydrate used extensively in processed foods as an inexpensive filler, thickener, and preservative. It is produced by a controlled hydrolysis process that breaks down starch into readily digestible chains of glucose molecules.
Once consumed, the body rapidly breaks down maltodextrin into individual glucose units in the small intestine. This rapid digestion leads to an extremely fast absorption rate, causing a sharp and significant spike in blood sugar levels. Maltodextrin often has a glycemic index (GI) value that is comparable to or even higher than table sugar (sucrose) or pure glucose, with estimates ranging from 85 to 136.
This high GI means that consuming foods with maltodextrin can trigger a rapid insulin response, similar to consuming simple sugars. For those with insulin resistance or diabetes, this rapid spike can worsen glycemic control and should be avoided.
Resistant Dextrin: The Fiber-Based Alternative
Resistant dextrin, also labeled as resistant maltodextrin or soluble corn fiber, is chemically altered to be indigestible by human enzymes. This modification creates new bonds that prevent breakdown in the small intestine, allowing the substance to function metabolically as a soluble fiber. It passes through the digestive tract essentially undigested, contributing minimal net carbohydrates to the diet.
Because it resists digestion and absorption, resistant dextrin has a negligible impact on blood sugar levels, resulting in a very low glycemic index. It travels to the large intestine where it is fermented by gut bacteria, acting as a prebiotic and supporting gut health.
The presence of this soluble fiber can also slow down gastric emptying and reduce the rate at which other carbohydrates are absorbed from a meal. This action helps to mitigate post-meal blood glucose excursions, which is why resistant dextrin is sometimes used in low-carb baking and products marketed for blood sugar management.
Identifying Dextrin on Food Labels
Consumers must look closely at the ingredient list, as the term “dextrin” alone is too vague to determine the blood sugar impact. The primary concern is “Maltodextrin,” which is a clear indicator of a high-glycemic carbohydrate and should be limited by those watching their glucose intake.
The terms that indicate the beneficial, fiber-based alternative are “Resistant Dextrin,” “Resistant Maltodextrin,” or “Soluble Corn Fiber.” These terms signify that the ingredient is largely indigestible and will not spike blood sugar. For those with blood sugar concerns, the best approach is to seek out products that list one of the “resistant” or “soluble fiber” names or, ideally, avoid products with maltodextrin altogether.