What neutralises phytic acid? A guide to reducing phytates for improved mineral absorption

October 14, 2025 •

4 min read

Research shows that phytic acid, an "antinutrient" in many plant seeds, binds to minerals like iron and zinc, hindering their absorption. Fortunately, several traditional food preparation techniques can effectively neutralise phytic acid, unlocking greater nutritional benefit from your food.

Quick Summary

This guide outlines effective kitchen methods such as soaking, sprouting, and fermenting that activate the phytase enzyme to break down phytic acid in grains, nuts, and legumes.

Key Points

Phytase is Key: The enzyme phytase, naturally present in many plants and microbes, is the primary agent that neutralises phytic acid.
Soaking is Simple: Soaking grains, legumes, and nuts overnight in warm water, often with an acidic medium like lemon juice, activates phytase and significantly reduces phytates.
Sprouting is Powerful: Germination or sprouting drastically increases a plant's natural phytase activity, making it one of the most effective ways to break down phytic acid.
Fermentation Boosts Bioavailability: Lactic acid fermentation, as in sourdough, leverages microbes to produce phytase, enhancing mineral availability.
Combine Methods for Best Results: For optimal reduction, combine methods like soaking with cooking or sprouting, rather than relying on a single technique.
Enhance Mineral Absorption: Pairing meals with vitamin C-rich foods can help counteract any remaining phytic acid effects on iron absorption.
Context is Everything: Phytic acid is only a concern in diets high in unprocessed plant foods and low in variety; a balanced diet naturally offsets most issues.

Understanding Phytic Acid and Its Impact

Phytic acid, or phytate, is the primary storage form of phosphorus in many plant tissues, including cereals, legumes, nuts, and seeds. While not an inherently harmful compound, it has a strong chelating property, meaning it binds to important dietary minerals like iron, zinc, calcium, and magnesium, making them less available for absorption in the human body. This can be a concern for those with diets heavily reliant on plant-based foods, such as vegans and vegetarians, or in areas where malnutrition is prevalent. For individuals with a balanced diet, the impact is less significant. However, neutralising phytic acid is a simple way to maximise the nutritional value of plant-based foods.

The Primary Neutralising Agent: Phytase Enzyme

The most potent agent for neutralising phytic acid is the enzyme phytase.

How Phytase Works

Phytase is a phosphatase enzyme that catalyzes the hydrolysis of phytic acid, breaking it down into myo-inositol and inorganic phosphate. This process frees up the minerals that were bound by the phytate, allowing for better absorption in the gut. While humans and other monogastric animals produce very little phytase, many plants naturally contain this enzyme, which can be activated through specific food preparation methods.

Phytase Availability

In Plants: The amount of endogenous phytase varies between plants. Grains like rye have a high concentration, while oats have a lower amount. The phytase can also be destroyed by high-heat processing, such as kilning.
In Microbes: Many microbes, including certain bacteria and fungi used in fermentation, also produce phytase.

Key Kitchen Methods to Neutralise Phytic Acid

There are several traditional and effective methods for reducing phytic acid content at home.

Soaking

Soaking is one of the most accessible methods to reduce phytate levels in grains, legumes, nuts, and seeds. This process involves covering the food in water for an extended period, which activates the naturally occurring phytase enzyme.

Soaking Procedure

Place the food item (e.g., whole grains, beans) in a large bowl.
Cover with warm, filtered water. For grains low in phytase like oats, add an acidic medium such as a splash of lemon juice or apple cider vinegar to further boost activity.
Allow to soak at room temperature for at least 7-12 hours, or overnight. For beans, soaking for 12-24 hours with a few water changes is recommended.
Drain the soaking water and rinse the food thoroughly before cooking. Do not cook with the soaking water, as it will contain the leached-out phytic acid.

Sprouting (Germination)

Sprouting activates the seed's natural processes, including a marked increase in phytase activity to make nutrients available for the growing plant. This method is highly effective at reducing phytic acid content.

Sprouting Procedure

Soak seeds or grains for 8-12 hours.
Rinse and drain the soaked seeds.
Keep them in a jar or sprouting tray and rinse them 2-3 times daily.
Once small sprouts appear (typically after 1-3 days), they can be consumed or cooked.

Fermentation

Fermentation, especially using lactic acid bacteria, is a powerful technique for breaking down phytic acid. It is particularly effective for grains used in bread-making.

Fermentation and Sourdough

The prolonged fermentation process in sourdough bread, involving a combination of wild yeast and lactic acid bacteria, provides an acidic environment that encourages both endogenous grain phytase and microbial phytase activity.
This results in a significantly lower phytate content compared to standard yeast-leavened bread.

Cooking

While less effective on its own, cooking, especially with sufficient heat and time (like boiling), can help reduce phytic acid. Combining cooking with prior preparation like soaking is the most effective approach for many foods, such as legumes.

Comparison of Phytic Acid Reduction Methods


Method	Effectiveness	Effort/Time	Best For
Soaking	Good. Reduces phytate significantly, especially with an acid medium.	Low effort, requires overnight planning.	Grains, beans, most nuts and seeds.
Sprouting	Very High. Drastically increases phytase activity.	Moderate effort, takes several days.	Most grains, legumes, and seeds.
Fermentation	Very High. Microbes and acidity break down phytate.	High effort, requires a starter and patience.	Grains (e.g., sourdough), legumes.
Cooking	Low to Moderate. Heat degrades some phytate, especially when combined with soaking.	Moderate effort, part of the normal cooking process.	Combined with other methods for grains and legumes.

Mitigating Effects and Choosing the Right Method

Beyond traditional preparation, combining certain foods can help. Eating meals high in phytic acid alongside foods rich in vitamin C can enhance iron absorption, counteracting phytic acid's effects. For most people eating a varied diet, a combination of these techniques, rather than full elimination, is a practical and healthy approach. Choosing a method depends on your needs. For daily oats, a simple overnight soak is easiest. For baking, using sprouted flour or a sourdough starter is ideal. For beans, soaking and thorough cooking remains the standard. The goal is not to fear foods containing phytic acid but to prepare them in a way that maximises their nutritional potential. The flexibility of these methods allows you to integrate them into your routine for better digestion and nutrient uptake.

Conclusion

Phytic acid is a natural compound in many healthy plant foods, but its ability to hinder mineral absorption can be mitigated with simple, traditional food preparation methods. By activating the enzyme phytase through soaking, sprouting, and fermentation, you can significantly reduce phytate levels and increase the bioavailability of essential minerals. Choosing the right method for the specific food, and pairing high-phytate meals with vitamin C sources, allows for a healthier and more nutritious diet, ensuring you get the most out of your plant-based foods. You can learn more about managing anti-nutrients from Harvard's School of Public Health. Are Anti-Nutrients Harmful? - Harvard T.H. Chan School of Public Health.

Frequently Asked Questions

Phytic acid is the main way plants store phosphorus in their seeds, nuts, grains, and legumes. It is sometimes called an "antinutrient" because it can bind to minerals, making them less available for human absorption.

It is referred to as an antinutrient because it has the ability to chelate, or bind to, dietary minerals such as iron, zinc, and calcium in the digestive tract. This reduces the absorption of these minerals by the body.

Soaking activates the naturally occurring phytase enzyme within the grain or legume. The phytase then starts to break down the phytic acid, reducing the content before consumption. Adding an acid like lemon juice can enhance this process.

Cooking does reduce phytic acid content to some degree, but it is not the most effective method on its own. It works best when combined with other methods like soaking or sprouting.

Foods with the highest concentrations include whole grains (especially bran), legumes like beans and lentils, nuts, and seeds. The phytic acid is concentrated in the outer layer.

No, it is not a major concern for most people who eat a well-balanced, varied diet. The mineral-binding effect is most significant in diets that are very high in phytate-rich foods and low in other mineral sources, such as some vegetarian or vegan diets.

Yes, commercial phytase enzymes are available and can be added to foods to help degrade phytic acid. They are often used in the animal feed industry and are being explored for human food applications.

Sprouting increases phytase activity in a wide range of grains and legumes, significantly reducing phytic acid. However, the exact percentage of reduction can vary depending on the food type and sprouting conditions.

For those concerned about mineral absorption, soaking nuts and seeds is a recommended step to reduce phytic acid. The process is similar to soaking grains, often with added salt, followed by drying or dehydrating.