Arrowroot has a slight nutritional edge over cornstarch. It contains more protein, fiber, and minerals, and it’s produced with less chemical processing. That said, both are starches used in small amounts as thickeners, so the real-world health difference in most recipes is modest. Where arrowroot pulls ahead more meaningfully is in digestibility, blood sugar impact, and what it doesn’t contain.
Nutritional Differences at a Glance
A one-cup serving of raw arrowroot (about 120 grams) delivers 78 calories, 16 grams of carbohydrates, 5 grams of protein, and 2 grams of fiber. It also supplies 15% of the daily value for iron, 17% for phosphorus, 11% for potassium, and a significant amount of folate. Cornstarch, by comparison, is almost pure carbohydrate. A similar serving of cornstarch contains roughly 488 calories, 117 grams of carbs, and virtually no protein, fiber, or meaningful vitamins.
This comparison deserves context, though. Nobody eats a full cup of either ingredient. A typical recipe calls for one or two tablespoons of thickener, so the absolute difference in any single dish is small. But if you’re choosing between the two regularly, arrowroot adds trace nutrients where cornstarch adds none.
Blood Sugar and Glycemic Impact
Arrowroot stands out for its low glycemic index. Boiled arrowroot tuber has a GI as low as 14, which is remarkably low for a starchy food. For reference, anything under 55 is classified as low GI. Arrowroot-based cookies tested in research consistently scored between 19 and 48, depending on the other ingredients, keeping them in the low-to-moderate range.
Cornstarch, being a refined pure starch, behaves differently in the body. It breaks down quickly into glucose, producing a faster and higher blood sugar spike. If you’re managing blood sugar levels or insulin resistance, arrowroot is the better option. The resistant starch in arrowroot is part of the reason for its gentler glycemic effect: your body can’t break down resistant starch in the small intestine, so it passes to the colon without spiking blood sugar the way digestible starch does.
Gut Health and Resistant Starch
Arrowroot contains resistant starch, a type of carbohydrate that functions more like fiber than like a typical starch. Instead of being digested and absorbed in your small intestine, resistant starch travels to your colon, where gut bacteria ferment it. That fermentation produces short-chain fatty acids, especially one called butyrate, which serves as the primary fuel for the cells lining your colon.
Butyrate does more than just feed colon cells. It reduces inflammation by dialing down the production of inflammatory signaling molecules, strengthens the gut barrier by boosting the proteins that hold intestinal cells tightly together, and promotes the secretion of the protective mucus layer that shields your intestinal lining. Over time, consistent intake of resistant starch encourages the growth of beneficial bacterial groups, creating a feedback loop where your gut becomes more efficient at producing these protective compounds.
A small pilot study tested arrowroot powder (10 mL three times daily for one month) in patients with irritable bowel syndrome who experienced diarrhea. Arrowroot reduced diarrhea during the treatment period and also eased abdominal pain. Interestingly, it had a longer-term effect on constipation even after participants stopped taking it, suggesting it may help normalize bowel function in both directions. The study was small, but it aligns with arrowroot’s traditional use as a digestive remedy.
Processing and Purity
The way each starch is extracted matters. Industrial cornstarch production typically involves high heat and chemical solvents to separate the starch from the rest of the corn kernel. Arrowroot powder, on the other hand, is usually extracted through a simpler, more direct process that skips the harsh chemicals and high temperatures. This keeps arrowroot closer to its natural state.
There’s also the GMO question. The vast majority of corn grown in the United States is genetically modified. Unless a cornstarch product is specifically labeled non-GMO or organic, it’s almost certainly derived from GM corn. Arrowroot is not a commercially modified crop, so GMO concerns don’t apply. For people who prefer to avoid genetically modified ingredients, arrowroot is straightforward in a way cornstarch often isn’t.
How They Perform in Cooking
Arrowroot and cornstarch aren’t perfectly interchangeable in the kitchen, and your choice can affect both the texture and nutritional quality of the finished dish. Arrowroot produces a clear, glossy finish and works well in acidic recipes like fruit sauces and citrus-based dressings, where cornstarch tends to lose its thickening power. Arrowroot also thickens at a lower temperature, which means you can preserve more heat-sensitive nutrients in whatever you’re cooking.
The tradeoff is that arrowroot doesn’t hold up to prolonged cooking. Add it near the end of the process, because extended boiling breaks down its structure and turns it thin and watery. It also doesn’t freeze and thaw well, so cornstarch is the better pick for dishes you plan to refrigerate or freeze. For dairy-based sauces, cornstarch is generally more reliable, as arrowroot can create a slimy texture when combined with milk or cream.
Who Benefits Most From Switching
For most people using a tablespoon of thickener in a recipe, the health difference between arrowroot and cornstarch is real but small. The people who benefit most from choosing arrowroot are those managing specific concerns. If you have blood sugar issues, arrowroot’s low glycemic index makes it a smarter choice. If you deal with digestive problems like IBS or chronic diarrhea, arrowroot’s resistant starch content and demonstrated effect on bowel regularity give it a clear advantage. If you have a corn allergy or sensitivity, arrowroot is an obvious alternative since it comes from a completely different plant family.
If you’re simply looking for a neutral thickener for a pie filling or gravy and have no particular health concerns, both will do the job. But when all factors are weighed together, arrowroot is the more nutritious, less processed, and more gut-friendly option.