Understanding Oxalates in Beans
Oxalates are naturally occurring compounds found in many plants, including a wide range of beans. For most people, consuming oxalates is not a concern, as the body can process them without issue. However, for individuals with a history of kidney stones, particularly calcium oxalate stones, or those with specific absorption disorders, managing dietary oxalate intake is often recommended. The oxalate content can differ significantly across various types of beans, making it important to know which varieties are highest and which are lower in this compound.
Oxalate levels are influenced by several factors, including the bean variety, growing conditions, and, importantly, preparation methods. Proper preparation can significantly reduce the soluble oxalate content, which is more readily absorbed by the body.
The Highest Oxalate Beans
Based on various studies and nutritional data, several bean varieties consistently appear on lists of high-oxalate foods.
- Navy Beans: Widely cited as one of the highest oxalate beans, with figures ranging from 76 mg to over 96 mg per half-cup serving.
- Soybeans: Another high-oxalate legume, especially when considering soy products. A cup of boiled soybeans can contain approximately 96 mg of oxalates. Soy products like soy milk and tofu can also have significant oxalate levels.
- Black Beans: These have been identified as having a moderately high oxalate content. One study noted black beans containing 62 mg per half-cup, while others have found higher values (e.g., 72 mg per 100g).
- Great Northern Beans: Similar to other white bean varieties, these are also considered high in oxalates, with reports showing around 66 mg per half-cup.
- White Beans (Phaseolus vulgaris L.): Research has shown that some varieties of white beans can have very high oxalate concentrations, with one study documenting 547.9 mg per 100g of dry weight.
Comparison of Bean Oxalate Levels
To illustrate the wide variation, here is a comparison table of several common bean types and their approximate oxalate content. The data reflects boiled beans and typical serving sizes, but note that figures can vary slightly between sources.
| Bean Type | Approximate Oxalate Content (mg per ½ cup) | Oxalate Category |
|---|---|---|
| Navy Beans | ~76-96 mg | High |
| Soybeans | ~48-96 mg | High |
| Black Beans | ~60-70 mg | Moderately High |
| Great Northern Beans | ~66 mg | Moderately High |
| White Beans (small) | ~66 mg | Moderately High |
| Refried Beans | ~16-60 mg | Moderate to High |
| Fava Beans | ~20 mg | Moderate |
| Red Kidney Beans | ~10-15 mg | Low |
| Pinto Beans | ~10 mg | Low |
| Black Eyed Peas | ~3 mg | Very Low |
Low Oxalate Bean Alternatives
For those needing to limit their oxalate intake, several delicious and nutritious bean options are naturally lower in oxalates. These include:
- Black-Eyed Peas: With as little as 3 mg of oxalate per half-cup, these are an excellent low-oxalate choice.
- Red Kidney Beans: Offering around 15 mg of oxalate per half-cup, these are a popular and low-oxalate option for many dishes.
- Garbanzo Beans (Chickpeas): A versatile and low-oxalate choice, typically containing low levels.
- Pinto Beans: These are considered a low-oxalate food, with a half-cup containing only about 10 mg.
- Mung Beans: Another very low-oxalate option, with approximately 8 mg per half-cup.
How to Reduce Oxalates in Beans
While avoiding high-oxalate beans is one strategy, preparation methods can also significantly decrease the oxalate content. Since oxalates are water-soluble, cooking techniques that involve water are particularly effective.
Best Practices for Reducing Oxalates:
- Soaking: Always soak dried beans overnight, or for several hours, before cooking. Discard the soaking water entirely, as this water will contain leached oxalates.
- Boiling: Boiling is more effective at removing oxalates than steaming or baking. Cook beans thoroughly in fresh water after soaking, and drain and discard the cooking water.
- Multiple Rinses: Rinse canned beans thoroughly with fresh water to remove any residual liquid and some of their oxalate content.
- Pairing with Calcium: Consuming high-oxalate foods with calcium-rich foods can help bind the oxalates in the digestive tract, preventing their absorption.
Conclusion
For individuals monitoring their oxalate intake, knowing which beans are highest in oxalates is a key aspect of managing their diet. While beans like navy beans and soybeans are notably high, many popular varieties like pinto, kidney, and black-eyed peas are much lower. By using simple preparation techniques like soaking and boiling, and by making strategic choices, it is possible to continue enjoying the nutritional benefits of beans while keeping oxalate levels in check. As with any specific dietary concern, consulting a healthcare provider or a registered dietitian is recommended for personalized advice.
