Phytates, also known as phytic acid, are naturally occurring compounds found in the seeds of plants, including nuts, grains, and legumes. They act as the plant's storage form of phosphorus. When consumed, phytates can bind to essential minerals like iron, zinc, and calcium, creating insoluble complexes that can inhibit their absorption by the human body. For this reason, they are sometimes referred to as 'anti-nutrients,' though they also offer health benefits such as antioxidant properties. While a balanced diet minimizes the risk of mineral deficiencies for most people, specific preparation methods can further reduce phytate content and improve nutrient availability. The good news is that cooking does help to reduce phytates, but its effectiveness is highly dependent on the cooking method and whether it's combined with other techniques.
The Role of Cooking in Phytate Reduction
Cooking, particularly with moist heat, helps to degrade phytic acid. The key is that the heat, especially when combined with water, can break down the phytic acid molecule. Boiling, steaming, and pressure cooking are all effective to varying degrees. However, simply cooking without first soaking is often less effective than when the two methods are combined. This is because soaking activates the enzyme phytase, which starts the process of breaking down phytic acid before heat is even applied.
Combining Soaking and Cooking
For a truly effective reduction, a two-step process is recommended, especially for legumes and whole grains. First, soak the food in water for several hours, then discard the soaking water. Next, cook the soaked food in fresh water. This process works on two fronts: the soaking activates phytase, and the subsequent cooking, with the water discarded, leaches away more of the phytate compounds. Studies have shown that combining these methods can lead to substantial reductions, with cooking legumes for one hour potentially reducing phytic acid content by up to 80%.
Pressure Cooking: A Highly Effective Option
Pressure cooking is one of the most effective culinary methods for reducing phytates, often yielding better results than traditional stove-top boiling. The combination of high temperature and pressure breaks down antinutrients like phytates more efficiently and in a shorter amount of time. For example, pressure cooking beans for a relatively short period can achieve a greater reduction in phytates than prolonged boiling. This is particularly useful for those who consume a lot of legumes and want to maximize their mineral intake.
Other Effective Methods
- Sprouting: Also known as germination, sprouting activates the seed's own enzymes, including phytase, which naturally breaks down phytic acid. This is an excellent preparatory step for grains and legumes before cooking. For some foods, like mung beans, boiling after sprouting is highly effective.
- Fermentation: Methods like making sourdough bread or fermenting legumes use microorganisms that produce organic acids. These acids promote phytate breakdown, making fermentation a powerful tool for reduction.
Cooking Methods Comparison Table
| Method | How It Works | Effectiveness | Notes |
|---|---|---|---|
| Boiling | Moist heat degrades phytates, which can leach into the cooking water. | Moderate to High, depending on duration and whether soaking is used. | Discarding the boiling water is crucial for removing leached phytates. |
| Pressure Cooking | High heat and pressure more efficiently break down phytates. | High, often better than boiling. | A quick and efficient method for legumes and grains. |
| Steaming | Indirect moist heat cooks food. | Lower than boiling or pressure cooking, as there is less leaching. | Best for vegetables, where phytate content is generally lower anyway. |
| Soaking + Cooking | Soaking activates phytase, followed by cooking and leaching. | Very High. | The most recommended domestic method for maximizing phytate reduction. |
| Sprouting + Cooking | Germination activates enzymes, followed by cooking. | Very High. | An additional step that further enhances phytate reduction. |
| Baking/Roasting | Dry heat is less effective at degrading phytates. | Low to Moderate. | Often done at lower temperatures than boiling, and no leaching occurs. |
Phytates in Perspective
While the reduction of phytates can be beneficial, especially for those on a vegetarian or vegan diet with high legume and grain intake, it is important to remember that these foods are also incredibly nutritious. Phytates are not the dietary villains they are sometimes made out to be. They possess antioxidant properties and can play a protective role in health. For most people eating a varied and balanced diet that includes both plant- and animal-based foods, the impact of phytates on mineral absorption is not a cause for concern. The aim is not to eliminate phytates completely, but to understand how to manage their levels in specific foods if needed.
Conclusion
In short, cooking does indeed get rid of phytates, but the degree of reduction is highly dependent on the method used. Combining a preparatory step like soaking or sprouting with a moist-heat cooking method like boiling or, even better, pressure cooking, is the most effective strategy for significantly lowering phytate content in legumes and grains. For a majority of individuals with a balanced diet, the occasional phytate-rich meal is not a problem. However, for those with high intake of un-prepped plant foods or with known mineral deficiencies, adopting these preparation techniques can be a simple and effective way to boost the bioavailability of key minerals like iron, zinc, and calcium. By taking these steps, you can enjoy all the benefits of nutritious plant-based foods while mitigating potential anti-nutrient effects.
How to reduce phytates effectively
Here’s a summary of the most effective strategies:
- Start with a soak: Always soak legumes and whole grains for several hours before cooking to activate phytase and begin the breakdown process.
- Discard the water: The soaking water, and often the cooking water, should be discarded to remove the leached phytates.
- Opt for pressure cooking: For legumes, using a pressure cooker can dramatically speed up and enhance phytate reduction.
- Consider sprouting: For certain grains and beans, sprouting can lead to even greater reductions than soaking alone.
- Fermentation is key: Utilize fermentation techniques, such as making sourdough bread, for high phytate grains like rye and wheat.
For more detailed information on anti-nutrients and a balanced diet, you can refer to authoritative sources such as the Harvard T.H. Chan School of Public Health.
