Maltodextrin: The Refined Starch With a Surprisingly High Glycemic Index

The ingredient list on your protein powder probably includes maltodextrin. So does your sports drink, your instant pudding, your flavored electrolyte mix, and possibly your protein bar.

It’s presented as a neutral, functional ingredient. What most labels don’t tell you is that this particular carbohydrate hits your bloodstream faster than table sugar.

What Maltodextrin Is

Maltodextrin is produced by partially hydrolyzing starch — breaking the long glucose chains shorter using water plus either enzymes or acid. The starting material is most often corn in the United States, though wheat, potato, and tapioca are also used.

The result is a mixture of glucose chains of varying length. The “dextrose equivalent” (DE) is a measure of how far hydrolysis has proceeded. Pure starch has a DE of 0. Pure glucose (dextrose) has a DE of 100. Maltodextrin has a DE between 3 and 20 — so it’s been partially broken down but still consists of short chains, not individual glucose molecules.

Once DE exceeds 20, the product is classified as corn syrup. At exactly 2 glucose units, it’s maltose. Maltodextrin sits between these in chain length.

The chains are short enough that the body digests them rapidly. Amylase (in saliva and the small intestine) can break these short chains to glucose quickly — faster than it breaks down longer starch molecules or slower-digesting carbohydrates like resistant starch.

The Glycemic Index Problem

The glycemic index (GI) measures how quickly a food raises blood glucose compared to pure glucose (GI = 100).

Here’s the striking comparison:

Maltodextrin raises blood glucose faster than table sugar and comparable to or faster than pure glucose, depending on the study and DE value.

This is the core paradox. On a Nutrition Facts panel, maltodextrin appears under “Total Carbohydrate” — and not under “Total Sugars.” A product can legally contain significant maltodextrin and display “0g sugars” because maltodextrin’s molecular chains technically exceed the 2-unit threshold for sugars. But the glycemic response is indistinguishable from sugar.

This matters most for people managing diabetes, insulin resistance, reactive hypoglycemia, or low-carbohydrate diets. A protein powder or “health bar” that lists maltodextrin among the first few ingredients is delivering a high-glycemic carbohydrate load that the product’s health framing often obscures.

What Maltodextrin Is Used For

Filler and bulk: cheap and bland, maltodextrin adds volume and weight without much flavor.

Carrier for spray-dried powders: one of its most important industrial uses. Spray drying turns liquids (flavor extracts, oils, pharmaceutical compounds) into dry powders by atomizing them with a hot gas. Maltodextrin acts as a carrier matrix that encapsulates oily or volatile ingredients, protecting them during drying and storage. Powdered flavors, instant coffee additions, and fat-soluble vitamin preparations often use maltodextrin this way.

Texture in low-fat products: fat gives food a particular mouthfeel and creaminess. When fat is removed from products, maltodextrin can partially replace the texture fat provides. This is why many low-fat salad dressings, reduced-fat dairy products, and “lite” versions of snacks contain maltodextrin.

Sports nutrition: rapidly digested carbohydrates are theoretically useful for glycogen replenishment during and after intense exercise. Maltodextrin’s high GI makes it relevant for sports drinks targeting athletes in sustained high-output activities.

Gut Microbiome Concerns

Animal research suggests maltodextrin may affect the gut microbiome in ways that aren’t beneficial.

A 2015 study by Bhattacharyya et al. found that maltodextrin supplementation in mice reduced Lactobacillus populations and increased the adhesion of an adherent-invasive E. coli strain to intestinal epithelial cells. Adherent-invasive E. coli is associated with Crohn’s disease pathology.

The Martinez et al. 2015 study, examining how whole grain consumption vs. refined grain consumption affects gut microbiome, showed that consuming highly refined carbohydrates (including maltodextrin) was associated with different microbiome profiles compared to whole grain consumption.

These are limited findings — rodent studies and observational human data, not controlled human trials. The clinical significance of these microbiome shifts isn’t established. But they fit a broader pattern: highly refined, rapidly absorbed carbohydrates may not be neutral for gut microbiome composition.

The Bottom Line

Maltodextrin is safe from a toxicological standpoint. The FDA lists it as GRAS. No evidence points to direct toxicity at dietary levels.

The real issue is metabolic and one of disclosure. A refined starch that raises blood sugar faster than table sugar, hidden in “Total Carbohydrate” rather than “Sugars,” can derail people who think they’re making a healthier choice by choosing a “no sugar added” protein powder or health bar that lists maltodextrin prominently.

Read ingredient lists. If maltodextrin is in the first three ingredients and you’re managing blood sugar, that product’s carbohydrate content deserves more scrutiny than the front of the package suggests.