What are examples of anti-nutrients?

January 9, 2026 •

4 min read

According to the Harvard School of Public Health, antinutrients are compounds in plant foods that can interfere with the body's absorption of certain essential nutrients. While the name can sound intimidating, most people on a balanced diet can consume them without significant harm, and many antinutrients offer surprising health benefits. Understanding what are examples of anti-nutrients can empower you to prepare your food in ways that mitigate their effects while retaining a nutrient-rich diet.

Quick Summary

Antinutrients are natural compounds in plant-based foods that can reduce the absorption of vitamins and minerals. Common types include phytates, lectins, oxalates, tannins, and goitrogens. Simple preparation methods like soaking, sprouting, and cooking can significantly reduce their levels in foods such as grains, legumes, and certain vegetables, allowing for optimal nutrient intake.

Key Points

Phytic Acid (Phytates): Found in whole grains, legumes, and nuts, it can block the absorption of minerals like iron, zinc, and calcium, but proper preparation can reduce its effects.
Lectins: Present in legumes and grains, active lectins can cause digestive issues, but they are easily deactivated by cooking, soaking, and fermentation.
Oxalates: Found in leafy greens, nuts, and other plants, oxalates can bind to calcium and increase the risk of kidney stones in susceptible individuals.
Tannins: Give tea, coffee, and wine their bitter taste and can inhibit iron absorption, but also offer potent antioxidant benefits.
Preparation is Key: Soaking, sprouting, cooking, and fermenting are effective methods to reduce anti-nutrient levels and enhance nutrient bioavailability.
Benefits Outweigh Risks: For most people, the health benefits of consuming nutrient-dense foods containing anti-nutrients outweigh any potential downsides, particularly when foods are properly prepared.
Individualized Approach: People with pre-existing conditions like kidney stones or mineral deficiencies should consult a healthcare professional for guidance on managing anti-nutrient intake.

Understanding the Most Common Anti-Nutrients

Anti-nutrients are naturally occurring compounds, mainly found in plants, that serve as a defense mechanism against pests and infection. In human consumption, they can inhibit the absorption of vitamins, minerals, and other nutrients. While many health-conscious individuals express concern over these compounds, it's important to recognize that the negative effects are usually only observed in those with diets heavily reliant on unprocessed foods or in cases of existing malnutrition. For the average person consuming a varied diet, the health benefits of eating plant-based foods far outweigh the concerns associated with anti-nutrients.

Phytates (Phytic Acid)

Phytic acid is a phosphorus-based compound found primarily in the bran of whole grains, seeds, nuts, and legumes. It binds to essential minerals like iron, zinc, magnesium, and calcium in the digestive tract, forming insoluble salts called phytates. Since humans lack the enzyme (phytase) to break down these phytates efficiently, these minerals cannot be absorbed. Despite this, phytic acid also acts as a potent antioxidant and may offer protective benefits against certain cancers and kidney stones.

Lectins

Lectins are a class of proteins found in almost all plants, especially in high concentrations in legumes (like kidney beans, soybeans, and peanuts) and whole grains. Raw or undercooked legumes contain active lectins that can resist digestion and bind to the gut wall, potentially causing digestive distress or inflammation. However, thorough cooking, soaking, sprouting, and fermenting effectively deactivates most lectins, making these foods safe to eat. When properly prepared, lectin-containing foods offer significant nutritional benefits, including fiber, vitamins, and minerals.

Oxalates (Oxalic Acid)

Oxalates are organic compounds present in a wide range of plant foods, including leafy greens (spinach, Swiss chard), nuts, beets, and cocoa. They bind to calcium, forming calcium oxalate crystals which are poorly absorbed and excreted from the body. For most individuals, this process is harmless, but for those prone to kidney stones, a high oxalate intake can be problematic as these crystals can accumulate. Boiling or steaming oxalate-rich vegetables can significantly reduce their oxalate content.

Tannins

Tannins are polyphenolic compounds found in many plant foods, including tea, coffee, wine, legumes, and certain fruits like grapes and apples. They are responsible for the bitter, astringent taste in these foods. Tannins can impair the digestion of proteins and decrease the absorption of iron. On the other hand, they possess strong antioxidant and anti-inflammatory properties.

Comparison of Major Anti-Nutrients


Anti-Nutrient	Food Sources	Main Effect on Absorption	Methods to Reduce	Potential Health Benefits
Phytates	Whole grains, legumes, nuts, seeds	Reduces absorption of iron, zinc, calcium, and magnesium	Soaking, sprouting, fermentation, cooking	Antioxidant effects, potential cancer protection
Lectins	Legumes, whole grains, nightshades	Interferes with absorption of calcium, iron, phosphorus, and zinc	Soaking, boiling, fermenting	Anti-cancer and anti-diabetic properties
Oxalates	Leafy greens, beets, nuts, tea, cocoa	Binds to calcium, reducing its absorption	Soaking, boiling, pairing with high-calcium foods	Antioxidant effects, potential heavy metal chelation
Tannins	Tea, coffee, wine, legumes, berries	Decreases iron and protein absorption	Cooking, peeling skins, brewing tea for less time	Antioxidant and anti-inflammatory properties
Goitrogens	Cruciferous vegetables (raw)	Interferes with iodine uptake by the thyroid gland	Steaming, boiling	Potential protective effects against certain cancers

The Role of Preparation in Reducing Anti-Nutrients

Fortunately, several traditional food preparation techniques can significantly reduce the anti-nutrient content of many foods, enhancing nutrient bioavailability.

Soaking: A simple and effective method for legumes, grains, and nuts. Soaking in water for several hours or overnight can help dissolve water-soluble anti-nutrients like phytates and tannins, allowing them to be drained away.
Sprouting (Germination): The process of germination naturally breaks down anti-nutrients as the seed begins to grow. Sprouting can dramatically reduce levels of phytates, and to a lesser extent, lectins and protease inhibitors.
Boiling and Cooking: High heat is particularly effective at destroying heat-sensitive anti-nutrients such as lectins and protease inhibitors. Boiling leafy greens can also significantly decrease oxalate levels. Pressure cooking is another highly effective method.
Fermentation: This ancient preservation method uses microorganisms like bacteria or yeast to break down carbohydrates and, as a result, reduces anti-nutrient content. Sourdough bread, yogurt, and fermented vegetables are all examples of foods where fermentation improves nutrient availability.

A Balanced Perspective

While the term “anti-nutrient” sounds negative, these compounds are not inherently evil. The foods that contain them—legumes, whole grains, nuts, and vegetables—are some of the most nutrient-dense foods available. Concerns about anti-nutrients are often overblown, especially for individuals eating a varied diet and properly preparing their food. In many cases, the potential benefits, such as their antioxidant effects, are substantial.

Those with specific health issues, like kidney stones or existing mineral deficiencies, should consult a healthcare provider or a registered dietitian to determine if limiting high-anti-nutrient foods is necessary. For the majority of people, incorporating a wide variety of whole, plant-based foods into their diet, prepared with traditional methods, is the best approach to maximize nutritional benefits without concern for anti-nutrients. For more information on dietary choices, consult reliable sources like the Harvard T.H. Chan School of Public Health.

Conclusion

Examples of anti-nutrients include phytates, lectins, oxalates, tannins, and goitrogens, which are found in many healthy plant foods like whole grains, legumes, nuts, seeds, and leafy greens. These compounds can interfere with nutrient absorption but are not a significant concern for most healthy people following a balanced and varied diet. The key to mitigating their effects lies in proper preparation techniques, including soaking, sprouting, and cooking, which can significantly reduce or eliminate anti-nutrient levels. In fact, many anti-nutrients also possess beneficial properties, such as antioxidants, that contribute positively to overall health. Focusing on a diverse, whole-food diet and practicing smart food preparation is a more beneficial strategy than trying to eliminate anti-nutrient-containing foods entirely.

Frequently Asked Questions

The most effective way to reduce antinutrients often involves a combination of methods. For example, soaking, sprouting, and fermenting grains and legumes can significantly decrease phytate and lectin content. Boiling is also highly effective for reducing lectins and oxalates.

No, most people do not need to avoid foods containing antinutrients. The health benefits of these plant-based foods, which are rich in fiber, vitamins, and minerals, typically outweigh the potential downsides, especially when prepared correctly.

The active lectins found in nightshade vegetables like tomatoes and potatoes are significantly reduced by cooking. For most people, consuming these foods cooked is not a concern. Claims linking them to gut problems are largely based on studies using concentrated, raw lectins, not typical dietary intake.

To reduce oxalate content in foods like spinach or chard, boiling is the most effective method, as a large portion of the oxalates will leach into the water. Pairing high-oxalate foods with high-calcium foods can also help bind the oxalates in the gut, preventing their absorption.

Soaking is very effective for removing water-soluble anti-nutrients like phytates and tannins, but not all of them. For lectins, soaking followed by cooking is the most reliable method of deactivation.

Yes, many antinutrients, such as tannins and phytates, are potent antioxidants with protective properties. Some research also suggests benefits related to blood sugar regulation and heart health.

Goitrogens are compounds that can interfere with thyroid function by blocking iodine uptake, and are found in raw cruciferous vegetables like broccoli, cabbage, and kale. Cooking significantly reduces their goitrogenic effect.