What are antinutritional factors and how do they affect your health?

December 9, 2025 •

4 min read

According to a 2020 review, antinutritional factors are naturally occurring compounds in many plant-based foods that interfere with nutrient absorption and utilization in the body. While these substances are often a plant's defense mechanism, understanding what they are and how they affect your health can help you optimize your diet.

Quick Summary

Antinutritional factors are natural compounds in foods that inhibit nutrient absorption and digestion. Common examples include phytates, lectins, and oxalates, which can be reduced through proper food preparation methods like soaking, cooking, and fermentation.

Key Points

Antinutritional factors are natural compounds: Found predominantly in plant-based foods like legumes, grains, and nuts, ANFs can reduce the body's ability to absorb certain nutrients.
Common ANFs include phytates, lectins, and oxalates: Phytates bind to minerals like zinc and iron; lectins can interfere with gut health if not properly prepared; and oxalates reduce calcium absorption.
Food processing significantly reduces ANFs: Simple methods like soaking, cooking, sprouting, and fermentation are highly effective at lowering the concentration of antinutrients.
The health impact depends on diet and preparation: A varied diet and proper food preparation typically mitigate any adverse effects, while exclusively raw or unprocessed diets may increase risk.
Some ANFs may offer health benefits: In small concentrations, certain antinutrients have been linked to potential health benefits, such as reduced blood glucose and cholesterol levels.
A balanced diet is the best defense: The benefits of consuming a wide variety of plant foods outweigh the minor risks posed by antinutrients when food is prepared properly.

What are antinutritional factors?

Antinutritional factors (ANFs) are compounds found in many foods, particularly in plant-based sources like legumes, grains, and nuts, that can interfere with the body's ability to absorb essential nutrients. While often discussed in a negative light, these bioactive compounds are a plant's natural defense mechanism against pests and microorganisms. The effects of ANFs are highly dependent on the amount consumed, overall dietary patterns, and how the food is prepared. For most people, a balanced diet that includes varied whole foods and traditional cooking methods is sufficient to mitigate their effects.

Common types of antinutritional factors

Understanding the most common ANFs helps in making informed food choices and preparation methods.

Phytates (Phytic Acid): Found in the outer layer of seeds, grains, nuts, and legumes, phytic acid is the primary storage form of phosphorus in many plants. It has a strong ability to bind to minerals like zinc, iron, calcium, and magnesium, forming insoluble compounds and reducing their bioavailability.
Lectins: These are sugar-binding proteins found in high concentrations in raw legumes, such as kidney beans and soybeans. If not properly cooked, some lectins can resist digestion, potentially disrupting the gut wall and interfering with nutrient absorption.
Oxalates (Oxalic Acid): Present in many plants, especially leafy greens like spinach and rhubarb, oxalates can bind to calcium and other minerals. This can prevent the body from absorbing calcium and may contribute to the formation of kidney stones in susceptible individuals when consumed in very large amounts.
Tannins: These phenolic compounds are responsible for the astringent taste in foods like tea, coffee, and legumes. Tannins can bind to proteins and digestive enzymes, reducing their effectiveness and decreasing protein digestibility.
Protease Inhibitors: Found in seeds and legumes like soybeans, these compounds interfere with protein-digesting enzymes, such as trypsin. This can reduce the digestibility of dietary protein and place stress on the pancreas.
Goitrogens: These compounds are found in cruciferous vegetables like broccoli, cabbage, and kale. They can interfere with iodine absorption and affect thyroid function, particularly if one has an iodine deficiency.

The impact on nutrient absorption

While a balanced diet naturally contains a wide array of nutrients that help counteract the effects of ANFs, high intake of raw or unprocessed foods rich in these compounds can pose a challenge. For instance, diets heavily reliant on unprocessed grains and legumes have been linked to mineral deficiencies in certain populations. However, it is important to remember that most ANFs are significantly reduced or eliminated through standard food preparation, and many studies also highlight the potential health benefits of some of these compounds in moderation.

Methods for reducing antinutritional factors

Fortunately, simple kitchen techniques can effectively reduce or eliminate most ANFs, making plant-based foods both safe and more nutritious.

Soaking: This is one of the easiest and most effective methods, particularly for legumes and grains. Soaking in water for several hours or overnight can leach out water-soluble ANFs like phytic acid and tannins.
Cooking: Applying heat through boiling, steaming, or pressure cooking is a powerful way to destroy heat-sensitive ANFs such as lectins and protease inhibitors. Longer cooking times typically lead to greater reductions.
Fermentation: This traditional process, used in making sourdough bread or fermented soybeans, utilizes microorganisms to break down ANFs. Fermentation significantly lowers phytate and lectin levels while increasing the bioavailability of minerals.
Sprouting (Germination): Sprouting seeds, grains, and legumes activates enzymes that degrade phytic acid and other ANFs, improving overall nutrient availability.
Milling and Dehulling: Removing the outer layers of grains and legumes, where many ANFs are concentrated, can substantially reduce their levels. However, this also removes fiber and other beneficial compounds.

Comparison of key antinutritional factors


Antinutritional Factor	Primary Food Source	Primary Impact	Reduction Method	Heat Sensitive?
Phytates	Grains, Legumes, Nuts, Seeds	Reduces mineral (zinc, iron, calcium) absorption	Soaking, Sprouting, Fermentation	No (requires more than just boiling)
Lectins	Legumes (especially raw beans), Grains	May disrupt gut barrier, reduce nutrient absorption	Boiling, Pressure Cooking	Yes (easily destroyed by high heat)
Oxalates	Leafy Greens, Nuts, Legumes	Reduces calcium absorption, risk of kidney stones	Boiling, Soaking	Yes (reduced by boiling)
Tannins	Tea, Coffee, Grapes, Legumes	Reduces protein digestibility, may inhibit enzymes	Soaking, Boiling	Yes (reduced by boiling)
Protease Inhibitors	Legumes (Soybeans, Chickpeas)	Interferes with protein digestion	Cooking, Soaking	Yes (destroyed by heat)
Goitrogens	Cruciferous vegetables (Cabbage, Broccoli)	Interferes with thyroid function	Cooking	Yes (can be reduced by cooking)

Conclusion: Navigating antinutritional factors in your diet

Antinutritional factors are a natural component of many staple plant-based foods, not a reason to avoid them. For the vast majority of people, the significant nutritional benefits of these foods far outweigh any potential negative impacts from ANFs. The key lies in traditional food preparation and a diverse, balanced diet. By soaking your beans, cooking your grains, and fermenting foods like sourdough, you can dramatically reduce the levels of these compounds. Moreover, consuming a variety of plant foods ensures that you get a wide range of nutrients, preventing overexposure to any single antinutrient. For those with specific health concerns, such as mineral deficiencies or thyroid issues, proper preparation is even more critical. Ultimately, being mindful of food processing and maintaining a varied whole-food diet is the most effective strategy for managing antinutritional factors and promoting optimal health. For further reading, a comprehensive review can be found here: A Review on Anti-Nutritional Factors.

Frequently Asked Questions

The most common antinutritional factors are phytates (found in grains, legumes, and nuts), lectins (in legumes and grains), and oxalates (in leafy greens and nuts).

You can reduce antinutritional factors through food preparation methods like soaking grains and legumes, cooking with high heat (boiling or pressure cooking), sprouting, and fermentation.

No, not always. While they can interfere with nutrient absorption at high levels, some studies suggest that in low concentrations, certain antinutrients like phytates and tannins may offer health benefits such as antioxidant properties or reduced cholesterol.

Cooking, especially boiling, is effective at removing heat-sensitive antinutrients like lectins and protease inhibitors. However, heat-stable compounds like phytates require additional processing, such as soaking, sprouting, or fermentation, for maximum reduction.

For most people consuming a varied diet, the risks associated with antinutrients are minimal. Traditional cooking methods used for plant-based foods are highly effective at reducing these compounds, and the overall health benefits of these foods far outweigh any minor drawbacks.

Phytates bind to important minerals like zinc, iron, and calcium, forming complexes that the body cannot easily absorb. Over time, a diet high in unprocessed phytates could contribute to mineral deficiencies.

Antinutrients are a consideration for plant-based diets, but not a cause for alarm. By incorporating proper preparation techniques—like soaking nuts and cooking legumes—vegans and vegetarians can ensure optimal nutrient absorption and still reap the full benefits of their diet.