Cornstarch, derived from the endosperm of the corn kernel, is a pantry staple prized for its ability to thicken sauces, gravies, and desserts. However, this extensive processing strips the corn of its bran and germ, removing virtually all fiber, protein, and essential micronutrients. This leaves behind a product that is essentially pure, starchy carbohydrate, which can have significant health implications if consumed in large quantities or as a frequent part of the diet. Understanding these potential downsides is crucial for making informed nutritional choices.
High Glycemic Impact and Blood Sugar Spikes
One of the most immediate concerns with cornstarch consumption is its effect on blood sugar levels. As a refined carbohydrate, cornstarch has a high glycemic index (GI), typically scoring between 77 and 88. The glycemic index measures how quickly a food causes blood sugar to rise after consumption. Foods with a high GI are rapidly digested and absorbed, leading to a quick and pronounced spike in blood glucose.
For most people, small amounts used in cooking for thickening are not a major issue. However, consuming larger quantities, such as in some gluten-free recipes that use cornstarch as a flour substitute, can lead to substantial blood sugar fluctuations. Over time, this constant spiking can contribute to insulin resistance, a precursor to type 2 diabetes. Individuals with diabetes, hypoglycemia, or other conditions requiring strict blood sugar management should be particularly mindful of their cornstarch intake.
Minimal Nutritional Value and 'Empty Calories'
Unlike whole grains, which contain valuable fiber, protein, and vitamins, cornstarch is almost completely devoid of nutritional benefits. A tablespoon contains approximately 30 calories, but offers zero protein and fiber. This makes it a source of what are often referred to as 'empty calories'—calories that provide energy without contributing meaningful nutrition.
While this lack of nutritional density may be insignificant when using a small amount to thicken a sauce, it becomes problematic if cornstarch forms a larger portion of the diet. Relying on processed foods that use cornstarch as a filler or thickener means missing out on vital nutrients that could be obtained from more wholesome, fiber-rich ingredients.
Potential for Weight Gain
Due to its high calorie and carbohydrate content and lack of fiber and protein, cornstarch can contribute to weight gain if overconsumed. Fiber and protein help promote feelings of fullness and satisfaction, while refined carbohydrates like cornstarch are digested quickly, which can lead to overeating. For those trying to manage their weight, choosing more nutrient-dense alternatives that offer sustained energy and satiety is a much better strategy.
Heart Health Concerns
The rapid digestion and high glycemic impact of refined carbohydrates, including cornstarch, have been linked to negative effects on heart health. Several studies have shown that diets high in such carbohydrates can increase levels of triglycerides, a type of fat in the bloodstream, which is a known risk factor for heart disease. For those concerned about cardiovascular health, reducing the intake of refined starches like cornstarch and replacing them with fiber-rich whole grains and other nutritious foods is recommended.
Digestive Sensitivities and Intolerance
For some individuals, consuming cornstarch can lead to uncomfortable digestive problems. Cornstarch intolerance, a sensitivity to corn products, can cause symptoms such as bloating, gas, and abdominal pain. This may be due to the body's inability to efficiently break down the starch molecules, leading to fermentation in the gut. Those with irritable bowel syndrome (IBS) or other functional gastrointestinal disorders may be particularly sensitive.
The Risks of Raw Cornstarch Consumption
While cooked cornstarch is generally considered safe in moderation, eating it raw is not recommended. Uncooked starches are more difficult for the body to digest, which can cause bloating and other gastrointestinal distress. In addition, raw starches may contain bacteria that are eliminated during cooking. A habitual craving for raw cornstarch, dirt, or other non-food items is a symptom of a disorder called pica, which can indicate an underlying nutritional deficiency, such as a lack of iron or zinc. Anyone experiencing this craving should consult a healthcare provider.
Healthier Alternatives to Cornstarch
For those looking to reduce their cornstarch intake or seeking more nutritious options, there are several excellent alternatives available, depending on the application. Healthline provides a good overview of some of these choices.
Cornstarch vs. Healthier Thickeners: A Comparison
| Thickener | Nutritional Value | Glycemic Impact | Best For | Flavor | Notes |
|---|---|---|---|---|---|
| Cornstarch | Pure carbohydrate, no fiber or protein | High (rapid spike) | Sauces, gravies, pie fillings | Neutral | Over-boiling can cause it to thin |
| Arrowroot Powder | Less processed, fewer calories than cornstarch | Lower than cornstarch | Clear sauces, glazes, acidic liquids | Neutral | Don't overcook or it can get slimy |
| Tapioca Starch | Minimal nutrients, but naturally gluten-free | Medium to high | Viscous fillings, glazes, frozen dishes | Neutral | Can become stringy if boiled |
| Whole Wheat Flour | Fiber, protein, vitamins | Lower than cornstarch | Gravies, opaque sauces, dough | Nutty/Earthier | Requires longer cooking to remove raw taste |
| Chia Seeds / Flaxseed | High in fiber, protein, Omega-3s | Low | Jams, smoothies, baked goods | Distinctive | Forms a gel; can alter texture |
Processed Foods Often Containing Cornstarch
Cornstarch isn't just in your pantry; it's a common additive in many processed and packaged foods. Being aware of these can help you better control your intake:
- Yogurts: Many yogurts, especially low-fat varieties, use cornstarch as a thickener. Real Greek yogurt naturally thickens without it.
- Cheeses: Shredded cheeses often contain cornstarch as an anti-caking agent to prevent clumping.
- Sauces and Dressings: Bottled sauces, salad dressings, and marinades frequently rely on cornstarch for their consistency.
- Soups and Stews: Canned and pre-made soups often use cornstarch as a thickening agent to improve texture.
- Baked Goods: Some gluten-free baked goods use cornstarch as a substitute for wheat flour, requiring larger quantities.
- Fried Foods: A thin layer of cornstarch can be used to achieve a crispy exterior on fried foods.
Conclusion
While cornstarch is a useful tool for culinary applications in small amounts, it is not a nutritious food and comes with potential health drawbacks when consumed excessively. Its high glycemic index can lead to rapid blood sugar spikes, and its lack of essential nutrients makes it an empty-calorie ingredient. For individuals with diabetes, heart concerns, or digestive sensitivities, moderating intake is key. Fortunately, a variety of healthier, nutrient-dense substitutes are available to help maintain both the texture of your recipes and the balance of your diet.
