A Nutritional Showdown: Potato Starch vs. Cornstarch
To determine if potato starch or cornstarch is healthier, a direct nutritional comparison is essential. While both are highly processed, refined carbohydrates, key differences exist in their composition, particularly regarding resistant starch content. These differences can have notable effects on digestion, blood sugar levels, and overall gut health.
Calorie and Macronutrient Breakdown
At first glance, the two starches appear very similar in their nutritional sparsity. They both consist almost entirely of carbohydrates, with negligible amounts of protein, fat, vitamins, and minerals. For example, a single tablespoon of potato starch has about 40 calories and 10 grams of carbohydrates, whereas a tablespoon of cornstarch contains around 30 calories and 7 grams of carbohydrates. However, since they are used in such small quantities, these minor calorie differences are generally insignificant to overall health.
The Resistant Starch Factor in Potato Starch
One of the most significant health-related differences lies in the presence of resistant starch. Raw potato starch is a potent source of Type 2 resistant starch, a type of fiber that the body cannot digest in the small intestine. Instead, it travels to the large intestine where it ferments, feeding beneficial gut bacteria. This process produces short-chain fatty acids, most importantly butyrate, which is a primary fuel source for the cells lining the colon. These actions contribute to improved gut health, reduced inflammation, and better metabolic function.
The Glycemic Index Impact
Cornstarch, on the other hand, is considered a pure, highly refined starch with a high glycemic index (GI), causing a rapid spike in blood sugar after consumption. This is because it lacks fiber and is quickly broken down into glucose. Potato starch, particularly in its raw form due to its resistant starch content, has a lower glycemic response, leading to a slower and more controlled rise in blood sugar. This makes potato starch a potentially better choice for individuals managing blood sugar levels, including those with type 2 diabetes.
Culinary Applications and How They Affect Health
The way each starch behaves in cooking also influences its health impact. Potato starch works best when added at the end of the cooking process at lower temperatures, as prolonged high heat can degrade its thickening properties and destroy the beneficial resistant starch. Cornstarch requires sustained heat to activate and thicken, and it holds up well under long cooking times. For health benefits from resistant starch, consuming raw potato starch (such as by stirring it into cold liquids like smoothies) is the most effective method, as cooking diminishes this beneficial component.
Comparison Table: Potato Starch vs. Cornstarch
| Feature | Potato Starch | Cornstarch |
|---|---|---|
| Primary Source | Potatoes | Maize (Corn) Kernels |
| Primary Health Benefit | Resistant starch for gut health | None (provides energy) |
| Resistant Starch Content | High in raw, unmodified form | Very low in standard form |
| Impact on Blood Sugar | Lower glycemic response (especially raw) | High glycemic index, quick blood sugar spike |
| Best for Thickening | Quick thickening, best for sauces, soups (added at the end) | Holds up well under prolonged high heat, suitable for gravies, pies |
| Texture | Silky, transparent finish | Opaque, glossy, gel-like finish |
| Allergies/Dietary | Grain-free, paleo-friendly | May not be suitable for those with a corn allergy |
Making an Informed Choice
Ultimately, deciding whether potato starch or cornstarch is healthier depends on your specific health goals. If you are aiming to improve gut health, regulate blood sugar, or increase your intake of fermentable fiber, raw potato starch is the clear winner due to its resistant starch content. This is particularly relevant for those on low-carb diets who want to boost their fiber intake without adding digestible carbohydrates.
However, for most people who use these starches as a minor ingredient, the health differences are negligible, and the choice often comes down to culinary preference. Both are gluten-free and can be part of a healthy diet in moderation. For thickening, follow the temperature guidelines: potato starch for quick, low-heat applications, and cornstarch for longer-cooking dishes. For a more comprehensive look at gut health and resistant starch, you can explore resources from the CSIRO Healthy Gut Diet book, a useful guide in understanding these dietary factors.
Conclusion
While cornstarch is a versatile and common thickener, its highly refined nature and potential for blood sugar spikes offer minimal health benefits beyond providing quick energy. In contrast, raw potato starch provides significant health advantages, primarily due to its resistant starch content, which supports gut microbiota and metabolic health. Therefore, for individuals seeking a healthier option with functional benefits, potato starch surpasses cornstarch. As with any food, mindful consumption as part of a balanced diet is key. For most home cooks, the decision can be driven by the specific culinary needs of the dish, as either can be used safely in small amounts. For targeted health benefits, a simple tablespoon of raw potato starch stirred into a cold liquid offers an easy dietary upgrade.
