Is Cornstarch Bad For You? A Registered Dietitian Answers

Is Cornstarch Bad For You? A Registered Dietitian Answers

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Cornstarch is used as a filler and thickening agent in many baking recipes. Since it's derived from corn, many consumers consider it to be a healthy option.

But does medical research suggest that cornstarch is bad for you? How does it compare to other baking thickeners? What's its nutritional value? And what health condition can cause cravings for corn starch?

In this article we’ll answer all of these questions and more as we highlight three reasons why cornstarch may be bad for you, explain what health condition causes cravings for cornstarch and suggest some healthier alternatives.

High Glycemic Index | Cornstarch Issue #1

Foods rich in carbohydrates can be measured on a scale called the glycemic index, which indicates how quickly the food raises blood sugar when eaten in isolation.

Blood sugar spikes can be harmful to the cardiovascular system even in nondiabetic subjects, as shown in a clinical trial published in the International Journal of Endocrinology.

The glycemic index is a scale from 1-100, and cornstarch is a 97 which is very high. This suggests that cornstarch can spike blood sugar to unhealthy levels if eaten in large portions. 

It’s worth noting that the glycemic index changes based on the composition of the meal. Eating carbs with fats, with acids and with proteins all lower the glycemic index of the meal overall. That being said, higher glycemic index foods are still considered somewhat less healthy than lower glycemic index foods like beans or oats which tend to be less processed.

Low in Nutrients | Cornstarch Issue #2

Cornstarch is a nutrient-poor food. Per calorie, it doesn’t offer much nutritional value. In large quantities it can provide a fraction of certain trace minerals like selenium, but in the amount used in processed foods and most recipes, cornstarch isn’t providing much other than filler carbs.

The USDA reports that 1 cup of cornstarch only provides 0.2% of the Daily Value (DV) of calcium, 3% of the DV of fiber and 1% of the DV of magnesium in over 400 calories total.

We recommend trying to eat nutrient-dense foods for most of the daily calories, as this dietary model has been shown in medical research to improve overall health outcomes.

Highly Processed | Cornstarch Issue #3

It’s a common misconception that corn starch is made by grinding whole corn kernels into a flour. However, that is corn flour, while corn starch is made by removing the outer layer of a corn kernel and processing the endosperm of the corn kernel into a consistent, fine white powder.

Much of the nutritional value of corn is lost during this manufacturing process.

Eating a minimally processed, whole-foods diet is generally associated with improved health, and cornstarch clearly doesn’t fit into that diet model.

We would consider corn flour to be healthy, but we recommend that consumers be wary of eating large amounts of highly refined products like cornstarch that are simply a white powder and don't at all resemble the original food (in this case corn).

What Can Cause Cornstarch Cravings?

A condition called pica can cause individuals to crave foods that provide essentially no nutritional value such as cornstarch, and even chalk and soap.

According to a 2016 medical review, pica is typically caused by iron deficiency. This suggests that individuals experiencing cravings to eat cornstarch in isolation should speak with a doctor about getting their iron levels tested.

If the cause is an iron deficiency and it's corrected with supplementation, the cravings for cornstarch will likely subside.

There's a large online community of people who make videos eating cornstarch for content. 

To give an example of this type of behavior, there's a YouTube video from a channel called "Addie ASMR" with a TikTok compliation of cornstarch eating:

Healthier Cornstarch Alternatives

Psyllium Husk

psyllium husk image

Psyllium husk is a fibrous powder made from a plant called Plantago ovata. It’s dense and can act as a thickening agent like cornstarch.

The reason we consider it healthier than cornstarch is because it’s much higher in fiber, and has a lower glycemic index. 100 grams (g) of psyllium husk powder contains 75 g of fiber according to the USDA.

100 g of cornstarch contains only 1.9 g of fiber.

We know from medical research that increased fiber intake benefits gastrointestinal (GI) health, and can aid in weight loss efforts, which is why psyllium husk is one of the most popular types of fiber and is used in gut health supplements like Colon Broom.

Yerba Prima Psyllium Husk Fiber is our top psyllium pick because it only contains one ingredient and was the psyllium product with the lowest lead levels based on ConsumerLab testing.

Coconut Flour

Coconut flour is made by drying whole coconuts, making it a minimally-processed alternative to cornstarch.

We consider it to be a healthier alternative because it’s much higher in nutrients. Per 100 g, coconut flour contains 1,867 milligrams (mg) potassium, 67 mg calcium and 33.3 g fiber according to the same USDA FoodData database linked in previous sections.

Cornstarch contains 3 mg potassium, 2 mg calcium and 1.9 g fiber for the same dose.

The database didn’t measure trace minerals like selenium and phosphorus, but it’s likely coconut flour would be higher in these too.

Clearly, coconut flour provides a much higher dose of vitamins and minerals than cornstarch. It can also make a great replacement because it’s relatively odorless and neutral.

Anthony's Organic Coconut Flour is our top coconut flour pick because it only has one ingredient (organic coconut) and costs well under $5 per pound. 

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We consider cornstarch to be bad for you if consumed in isolation or eaten in large quantities. It's likely fine when used in normal quantities as part of a baking recipe, but we'd still recommend replacing it with more nutritious alternatives like psyllium husk or coconut flour.

Cornstarch can cause blood sugar spikes, and it's highly-processed and very low in nutrients per serving.

A medical condition called pica which is often caused by iron deficiency can cause cravings for non-nutritive foods like cornstarch, so we'd recommend that individuals who crave eating cornstarch raw speak with a doctor about getting a blood test for iron.