Cornstarch is a white, powdery substance extracted from the endosperm of the corn kernel, primarily composed of pure starch. It is a highly refined ingredient, and its main purpose in the kitchen is to act as a thickening agent for gravies, sauces, and soups when heated with liquid. While its use in small amounts for cooking is common, consuming cornstarch on its own or in large quantities is generally not recommended due to its minimal nutritional value and rapid impact on the body.
The Nutritional Reality of Cornstarch
Cornstarch is essentially 100% carbohydrate, making it a source of what are often called “empty calories.” This is because the wet milling process used to extract the starch from the corn kernel strips away nearly all other nutrients. A single tablespoon of cornstarch contains approximately 30 calories and 7 grams of carbohydrates, with virtually no protein, fat, or fiber.
The refining process removes the corn kernel’s outer layer and germ, which are the parts containing the majority of the vitamins and minerals. Consequently, cornstarch offers no significant amounts of dietary fiber, B vitamins, or other micronutrients necessary for bodily function. Consuming large amounts of cornstarch contributes energy to the diet but does not provide the nutritional building blocks the body needs for health.
How Cornstarch Impacts Digestion and Blood Sugar
The body processes cornstarch very quickly because of its highly refined nature and lack of fiber. Fiber is an important nutrient that normally slows down the absorption of sugar into the bloodstream, but cornstarch contains almost none. This means that when consumed, cornstarch is rapidly broken down by digestive enzymes into glucose, which is the body’s primary form of sugar.
The rapid conversion of starch to glucose gives cornstarch a high glycemic index (GI), a measure of how quickly a food can raise blood sugar levels. Foods with a high GI can cause a rapid spike in blood sugar, which triggers a corresponding surge of insulin release from the pancreas. This rapid rise and fall of blood sugar can be particularly problematic for individuals attempting to manage their blood sugar, such as those with type 2 diabetes.
Regularly consuming foods that cause large blood sugar fluctuations can strain the body’s metabolic system over time. The high GI of cornstarch, especially when cooked, means it acts as a fast-digesting carbohydrate, providing a quick burst of energy that is not sustained.
Health Risks Associated with Excessive Consumption
Regularly consuming excessive amounts of cornstarch can lead to several cumulative health concerns. The high caloric density and lack of satiety from cornstarch contribute to a significant risk of weight gain. Since it is digested quickly, it does little to make a person feel full, potentially leading to overconsumption of total calories throughout the day.
The starchy nature of cornstarch also poses a risk to oral health, as starches can adhere to the teeth and promote decay. Bacteria in the mouth feed on these residual carbohydrates, producing acids that erode tooth enamel over time. Excessive intake is also associated with potential digestive discomfort, including constipation and bloating, particularly if it replaces fiber-rich foods in the diet.
A strong, compulsive craving for non-food starches, including cornstarch, is a condition known as amylophagia, which is a subtype of the eating disorder Pica. This behavior is frequently linked to underlying nutritional deficiencies, most commonly iron deficiency anemia or zinc deficiency.
If a person experiences severe or compulsive cravings for cornstarch, consultation with a healthcare provider is important. Overconsumption can lead to malnutrition because it displaces nutrient-dense foods from the diet, compounding the existing deficiency. Furthermore, consuming large amounts of refined starch can potentially trigger or worsen conditions like diabetes due to the massive influx of sugar into the bloodstream.