Phytic Acid in Plant Based Foods

Phytic acid, also known as phytate or inositol hexakisphosphate (IP6), is the storage form of phosphorus found naturally in plant seeds, legumes, grains, nuts, and pseudocereals. It acts as an antioxidant in both the plant and in the human body, protecting against oxidative damage.

Phytase is an enzyme that breaks down phytic acid into inositol and phosphate, releasing the bound minerals. Plants contain their own phytase; humans produce very little intestinal phytase. Food processing techniques that activate plant phytase — soaking, sprouting, fermenting, and slow heating of whole grain doughs — are the most practical ways to reduce dietary phytic acid and improve mineral bioavailability.

Traditional food preparation methods significantly reduce phytic acid content. Soaking grains and legumes overnight activates enzymes that begin breaking down phytic acid. Sprouting further reduces it — sprouts can have up to 50% less phytic acid than whole seeds. Fermenting (as in sourdough bread) is highly effective. Cooking at high temperatures also reduces phytic acid. For example, canned beans have less phytic acid than dried beans because of the heating process. For people concerned about mineral absorption, combining these methods (soak, then sprout, then cook) provides maximum reduction.

Yes, phytic acid can reduce the absorption of non-heme iron and zinc in the same meal by binding to these minerals. However, the effect is limited when overall mineral intake is adequate, and a varied plant based diet provides multiple sources of iron and zinc across different meals and days. Additionally, vitamin C (from citrus, tomatoes, peppers) significantly enhances iron absorption and counteracts phytic acid's effect.

Yes — sprouting is one of the most effective methods. During sprouting, the seed activates its own phytase enzymes to break down phytic acid, making minerals more bioavailable. Sprouted grains, beans, and seeds typically have 30–50% less phytic acid than unsprouted versions. Sprouted grain breads (like Ezekiel bread) are popular specifically for this reason.

Sourdough fermentation is exceptionally effective at reducing phytic acid because lactic acid bacteria acidify the dough, activating phytase enzymes and breaking down phytic acid over several hours. Studies show sourdough whole grain bread can have up to 60–90% less phytic acid than conventionally leavened whole grain bread — giving much better mineral bioavailability despite using the same flour.