What are the effects of phytates on the body?

October 30, 2025 •

5 min read

Phytates, also known as phytic acid, are natural compounds found in plant seeds, grains, nuts, and legumes, and are the primary storage form of phosphorus in these foods. However, these compounds also have a notable effect on the body, acting as both an 'anti-nutrient' that blocks mineral absorption and a powerful, health-promoting antioxidant.

Quick Summary

Phytates have a dual impact on the body, famously blocking mineral absorption but also offering significant health benefits like antioxidant effects and blood sugar control.

Key Points

Dual Function: Phytates act as both mineral-binding anti-nutrients and health-beneficial antioxidants, influencing nutrient absorption and cellular processes.
Mineral Absorption Inhibited: They can decrease the absorption of minerals like iron, zinc, calcium, and magnesium by forming insoluble complexes in the gut.
Not a Major Concern for Balanced Diets: For most people with a varied diet, the anti-nutrient effect of phytates is minor, and the overall benefits of the whole foods are significant.
Health Benefits: Phytates provide powerful antioxidant effects, help manage blood sugar, protect against certain cancers, and may support cardiovascular and bone health.
Reducing Phytates in Food: Simple preparation methods like soaking, sprouting, and fermentation effectively reduce phytate content in grains and legumes.
High-Risk Groups: Individuals on strict vegan or vegetarian diets, or those with existing mineral deficiencies, may need to pay closer attention to their phytate intake and preparation methods.
Pairing for Better Absorption: Combining phytate-rich foods with enhancers like vitamin C or meat can help counteract their negative effect on mineral uptake.

Phytates, or phytic acid, are compounds found in abundance in many plant-based foods, particularly whole grains, legumes, nuts, and seeds. Historically, their primary claim to fame was as an "anti-nutrient" due to their ability to bind to essential minerals, but modern research has revealed a more complex picture. For individuals with a balanced diet, the presence of phytates is generally not a concern, and the health benefits of phytate-rich foods far outweigh the potential negative effects on mineral absorption. However, for those with nutrient deficiencies or in regions heavily reliant on unprocessed plant staples, understanding this dual role is crucial.

The Dual Nature of Phytates: Anti-Nutrient vs. Beneficial Compound

At the core of the phytate debate is its powerful chelating ability—the capacity to bind positively charged mineral ions. This creates a double-edged sword, as this property both inhibits mineral absorption in the digestive tract and provides protective health benefits throughout the body.

The Anti-Nutrient Effect: Inhibited Mineral Absorption

Phytates can significantly decrease the bioavailability of key minerals by binding to them, forming insoluble complexes that the human body cannot easily absorb. Humans lack the necessary endogenous phytase enzyme in sufficient quantities to break down phytates, so these mineral complexes often pass through the digestive system unabsorbed. The most affected minerals include:

Iron: Phytates strongly inhibit the absorption of non-heme iron (the type found in plants). This is a significant concern for populations at risk of anemia, such as women of childbearing age and those in developing countries.
Zinc: Zinc absorption is particularly sensitive to phytates, with high phytate-to-zinc molar ratios in the diet linked to reduced bioavailability. Calcium can further exacerbate this effect.
Calcium: Phytates can bind to calcium, especially in the upper small intestine where absorption typically occurs. The effect on calcium absorption, however, can be less pronounced than on iron or zinc due to higher calcium content in many plant foods and some colonic absorption.
Magnesium and Copper: While less intensely studied, phytates have also been shown to affect the absorption of magnesium and copper.

This anti-nutrient effect is primarily a concern for those with marginal nutritional status or for individuals whose diets are predominantly based on unrefined grains and legumes.

The Beneficial Side: A Natural Antioxidant and More

Despite their mineral-binding properties, phytates are not inherently bad and offer a range of health benefits.

Potent Antioxidant: Phytates are powerful natural antioxidants. They work by chelating iron, which prevents iron-catalyzed oxidative reactions and the formation of harmful hydroxyl radicals. This antioxidant action may protect against various inflammatory diseases.
Anti-Cancer Potential: The antioxidant effects and ability to modulate cell signaling pathways suggest that phytates have anti-cancer properties. Studies indicate they may inhibit the growth of various cancer cell lines and offer protective effects against cancers, including colon and breast cancer.
Blood Sugar Control: Phytates can help regulate blood glucose by slowing down the digestion of starch and controlling insulin secretion. This makes phytate-rich foods a good choice for managing and preventing diabetes.
Cardiovascular Health: Research suggests phytates can improve cardiovascular health by reducing pathological calcifications in blood vessels. They have also been associated with lower levels of serum cholesterol and triglycerides.
Bone Health: Paradoxically, while they can reduce calcium absorption, phytates may also protect bone health. Some studies show that phytates can inhibit the dissolution of bone hydroxyapatite, potentially playing a role in preventing osteoporosis. Epidemiological studies have also linked higher phytate intake with higher bone mineral density in some populations.
Prevention of Kidney Stones: Phytates can inhibit the crystallization of calcium salts, which is the primary component of kidney stones. This suggests a preventative role for phytates against renal lithiasis.

Comparison: Phytate's Negative Effects vs. Health Benefits


Aspect	Negative Effects	Health Benefits
Mineral Absorption	Inhibits absorption of key minerals like iron, zinc, calcium, and magnesium.	Not directly beneficial, but the source foods are rich in nutrients.
Oxidative Stress	Not applicable (no pro-oxidant activity observed).	Strong antioxidant activity by chelating iron, preventing free radical damage.
Metabolic Control	Can affect digestion of other food components like proteins and starches at high concentrations.	Improves blood glucose control and can lower cholesterol and triglyceride levels.
Cancer Risk	None documented in this context.	Potential anti-cancer effects by inhibiting cell proliferation and promoting apoptosis.
Bone Health	Can potentially reduce calcium absorption over time with poor diet.	May inhibit bone resorption and protect against osteoporosis.
Kidney Health	None documented.	Inhibits the formation of calcium salt crystals, helping to prevent kidney stones.

Minimizing Phytate's Anti-Nutrient Effects

While avoiding phytate-rich foods is unnecessary and inadvisable due to their numerous benefits, several traditional food preparation methods can significantly reduce their anti-nutrient effects. These techniques activate the plant's own phytase enzyme, which breaks down the phytic acid.

Soaking: Soaking grains, legumes, and seeds in water for several hours, often overnight, can activate phytase and reduce phytate content. Using warm water and an acidic medium, like a splash of vinegar, can enhance this process, especially for grains with lower natural phytase activity.
Sprouting (Germination): The sprouting process involves hydrating and germinating seeds, grains, and legumes. This naturally triggers phytase activity to break down phytic acid and release stored minerals and phosphorus for the new plant.
Fermentation: Lactic acid fermentation, used in making sourdough bread or tempeh, produces organic acids that facilitate phytate breakdown. Prolonged fermentation is particularly effective.
Cooking: While less effective than other methods on their own, boiling or pressure-cooking can further reduce phytate levels in foods like legumes, with some studies reporting reductions of up to 80% with prolonged cooking.
Combine with Nutrient Enhancers: Consuming phytate-rich foods alongside mineral absorption enhancers can offset the anti-nutrient effect. For instance, pairing iron-rich, phytate-containing foods with a source of vitamin C or meat can boost iron absorption significantly.

Conclusion

What are the effects of phytates on the body? The science shows a balance between their anti-nutrient properties and their impressive health benefits. While they can impair mineral absorption, particularly in diets heavily dominated by unprocessed, phytate-rich foods, this concern is generally low for individuals with varied, balanced diets in developed countries. The substantial benefits—including antioxidant protection, blood sugar control, and potential anti-cancer effects— underscore why foods containing phytates, such as whole grains, nuts, and legumes, are staples of a healthy diet. Using simple preparation techniques like soaking and sprouting can further enhance the nutritional value of these foods. For those concerned about mineral status, diversifying the diet and employing these preparation methods is a sensible and effective strategy.

Frequently Asked Questions

Phytates are found in high concentrations in many plant foods, including whole grains (e.g., wheat, rice, oats), legumes (e.g., beans, lentils, chickpeas), nuts (e.g., almonds, walnuts), and seeds (e.g., sesame, flax).

No, phytates are not inherently bad. They have a dual nature; while they can inhibit some mineral absorption, they also provide significant health benefits as potent antioxidants and are found in many healthy foods. For most people with a balanced diet, the benefits far outweigh the minor anti-nutrient effects.

You can reduce phytate levels through preparation methods like soaking grains and legumes overnight, sprouting, and fermentation (e.g., sourdough bread). Cooking can also help, particularly with long-duration methods like boiling.

Phytates can potentially contribute to mineral deficiencies if consumed in large quantities as part of a monotonous, unprocessed, plant-based diet, especially in individuals with poor overall mineral intake. However, for those on a balanced diet, this is not typically a concern.

Yes, research suggests that phytates may have anti-cancer properties. Their antioxidant activity helps prevent oxidative damage, and studies indicate they may inhibit cancer cell growth and promote apoptosis.

Phytates can bind to calcium, potentially reducing its absorption, especially when dietary calcium intake is low. However, some evidence suggests phytates may also inhibit bone resorption, potentially helping with conditions like osteoporosis.

No, it is not. While refined grains have lower phytate levels due to the removal of the bran, this process also strips away dietary fiber, minerals, and other nutrients. Whole grains, even with phytates, are generally healthier and contain more vitamins and minerals overall.