Top Bean Varieties Highest in Starch
Starch is a complex carbohydrate that serves as a primary energy source, and certain legumes are excellent sources. While all beans contain some starch, varieties like kidney, navy, and pinto beans consistently rank among the highest. The starch content and its specific composition, particularly the ratio of amylose to amylopectin, determine how it affects digestion and overall health.
Kidney Beans: The Amylose Leader
Kidney beans are a leading contender for the highest starch content, with studies reporting that starch can make up 25–45% of their dry matter. A significant portion of this is resistant starch, particularly the high amylose content, which gives the bean starches a unique structure. The superior functional properties of kidney bean starches, including their ability to regulate blood sugar, make them especially beneficial for managing conditions like diabetes. Their high resistant starch content is a key reason why they are a healthy dietary carbohydrate.
Navy Beans: A Rich Source of Complex Carbs
Navy beans are another top-tier starchy bean. Boiled navy beans contain a high carbohydrate load, primarily in the form of starch, providing a steady release of energy. In addition to their high starch content, navy beans are a nutritional powerhouse, packed with fiber, protein, and essential minerals like folate and magnesium.
Pinto Beans: High Starch with Resistant Properties
Pinto beans are well-known for their high complex carbohydrate and starch content. Studies have shown they contain significant levels of resistant starch, especially after being cooked and cooled. This process of cooling causes some of the starch to recrystallize, increasing its resistant starch content, which is beneficial for gut health.
The Role of Resistant Starch
Resistant starch is a type of starch that is not digested in the small intestine but is instead fermented by beneficial bacteria in the large intestine. This fermentation process produces short-chain fatty acids, which provide numerous health benefits, including supporting a healthy colon and gut microbiome. Legumes, especially those high in amylose like kidney beans, are excellent sources of resistant starch. The resistant starch content in beans can be influenced by how they are prepared. For example, cooking beans and then cooling them for 24 hours can increase their resistant starch levels.
Key Functions of Resistant Starch
- Supports Gut Health: Feeds beneficial gut bacteria, promoting a diverse and healthy gut microbiome.
- Improves Digestion: Acts like dietary fiber, aiding in regular bowel movements and potentially preventing digestive conditions.
- Regulates Blood Sugar: Can help lower and stabilize blood glucose levels, which is particularly beneficial for people with diabetes.
- Promotes Satiety: Contributes to a feeling of fullness, which can assist with weight management.
Comparison of High-Starch Beans
To better understand the differences, here is a comparison of the typical characteristics of these high-starch beans. Note that nutritional values can vary slightly based on growing conditions and cooking methods.
| Feature | Kidney Beans | Navy Beans | Pinto Beans |
|---|---|---|---|
| Starch Content (Dry Basis) | 25–45% | Up to 33% | Substantial |
| Resistant Starch | Very High (especially after cooling) | High | High (increases with cooling) |
| Amylose Content | High apparent amylose content | High | High amylose |
| Primary Use | Chili, salads, simmered dishes | Baked beans, stews, soups | Refried beans, burritos, chili |
| Health Benefit Focus | Blood sugar regulation | Digestion and nutrient absorption | Gut health improvement |
Cooking Methods to Maximize Starch Benefits
Maximizing the resistant starch in your beans is a simple process. Soaking and cooking dried beans properly are the first steps. A hot soak can help dissolve some of the carbohydrates that cause gas, and the subsequent cooking will soften the beans. However, the most effective method for increasing resistant starch is to cool the cooked beans. The process of retrogradation, where starches recrystallize upon cooling, increases the resistant starch content.
Simple Steps for High-Starch Beans
- Soak: To reduce cooking time and intestinal gas, soak dry beans in a large pot of water overnight or for at least 4 hours.
- Cook: Drain and rinse the soaked beans, then cover them with fresh water. Simmer gently until tender. Avoid aggressive boiling, which can cause them to break apart.
- Cool: After cooking, let the beans cool completely. Refrigerating them for up to 24 hours will significantly increase the resistant starch content.
Conclusion
Kidney, navy, and pinto beans are among the varieties highest in starch. This is not a negative nutritional trait, but rather a source of complex carbohydrates and beneficial resistant starch. Resistant starch supports gut health, improves digestion, and helps regulate blood sugar, offering significant health advantages. Proper cooking methods, including the crucial cooling step, can further enhance these benefits. By incorporating these starchy beans into your diet, you can enjoy delicious, nutrient-dense meals that support your overall wellness. For more on legume nutrition, see the Harvard T.H. Chan School of Public Health's detailed resources on beans and resistant starch.
