Phytic acid can affect how the body absorbs some minerals, including iron. It may contribute to mineral deficiencies over time, but this is rarely a concern for people who eat well-balanced diets.
Phytic acid is a unique natural substance found in plant seeds.
It has received considerable attention due to its effects on mineral absorption. Phytic acid prevents the absorption of iron, zinc, and calcium and may promote mineral deficiencies (1).
That’s why it is often referred to as an anti-nutrient. It’s not that simple, though — phytic acid also has a number of health benefits.
This article takes a detailed look at phytic acid and its overall effects on health.
Share on PinterestCriene/Twenty20What is phytic acid?
Phytic acid, or phytate, is found in plant seeds.
It serves as the main form of storage for phosphorus in the seeds. Then, when seeds sprout, phytate is broken down and the phosphorus is released. The phosphorus will be used by the young plant.
Phytic acid is also known as inositol hexaphosphate, or IP6.
It’s often used commercially as a preservative due to its antioxidant properties.
SummaryPhytic acid is found in plant seeds, where it functions as the main storage form of phosphorus.
Phytic acid in foods
Phytic acid is found only in foods that come from plants.
All edible seeds, grains, legumes, and nuts contain phytic acid in varying quantities. Small amounts are also found in roots and tubers.
The following table shows the amount contained in a few high-phytate foods, as a percentage of dry weight (2):
FoodAmount of phytic acidalmonds0.4–9.4%beans0.6–2.4%Brazil nuts0.3–6.3%hazelnuts0.2–0.9%lentils0.3–1.5%maize, corn0.7–2.2%peanuts0.2–4.5%peas0.2–1.2%rice0.1–1.1%rice bran2.6–8.7%sesame seeds1.4–5.4%soybeans1.0–2.2%tofu0.1–2.9%walnuts0.2–6.7%wheat0.4–1.4%wheat bran2.1–7.3%wheat germ1.1–3.9%As you can see, the phytic acid content in these foods can really vary. For example, the amount contained in almonds can range from very little to more than 20 times that amount.
SummaryPhytic acid is found in plant seeds, nuts, legumes, and grains. The amount contained in these foods is highly variable.
Phytic acid impairs mineral absorption
Phytic acid impairs (prevents) the absorption of zinc, iron, calcium, and other minerals by your body (1, 3).
This applies to a single meal, not overall nutrient absorption throughout the day. In other words, phytic acid primarily reduces your mineral absorption during the meal but doesn’t have major effects on subsequent meals.
For example, snacking on nuts between meals could reduce the amount of iron, zinc, and calcium you absorb from these nuts but not from the meal you eat a few hours later.
However, when you eat high phytate foods with most of your meals, mineral deficiencies may develop over time.
This is rarely a concern for those who follow well-balanced diets, but may be a significant issue during periods of malnutrition and in developing countries where the main food source is grains or legumes.
SummaryPhytic acid impairs the body’s absorption of iron, zinc, and calcium. It may contribute to mineral deficiencies over time, but this is rarely a concern for those following well-balanced diets.
How to reduce phytic acid in foods?
Avoiding all foods that contain phytic acid is not ideal, because many of them are healthy and nutritious.
Also, in many developing countries, food is scarce and people need to rely on grains and legumes as their main dietary staples.
Instead of avoiding these foods, you can try several preparation methods that can significantly reduce the phytic acid content of foods.
Here are the most commonly used methods:
- Soaking. Cereals and legumes are often soaked in water overnight to reduce their phytate content (4, 5).
- Sprouting. The sprouting of seeds, grains, and legumes — also known as germination — causes phytate breakdown (4, 6, 7).
- Fermentation. Organic acids, formed during fermentation, promote phytate breakdown. Lactic acid fermentation is the preferred method, such as in the making of sourdough (4, 8, 9).
Combining these methods can reduce phytate content substantially.
For example, cooking legumes for 1 hour can reduce their phytic acid content by up to 80% (10).
In addition, sprouting and lactic acid fermentation help degrade (break down) phytic acid (11).
SummarySeveral methods can be used to reduce the phytic acid content of foods, including soaking, sprouting, and fermentation.
Health benefits of phytic acid
Phytic acid is a good example of a nutrient that is both good and bad, depending on the circumstances.
For most people, it’s a healthy plant compound that serves as an antioxidant and may protect against insulin resistance (1, 4, 12).
Scientists have even suggested that phytic acid may be part of the reason why whole grains have been associated with a reduced risk of colon cancer (13).
SummaryPhytic acid may have several positive health effects, such as protection against oxidative damage and insulin resistance.
Is phytic acid a health concern?
Phytic acid is not a health concern for those who follow a balanced diet.
However, those at risk of an iron or zinc deficiency should diversify their diets and not include high phytate foods in all meals.
This may be especially important for those with an iron deficiency, as well as vegetarians and vegans (1, 4, 14).
There are two types of iron in foods: heme iron and non-heme iron.
Heme iron is found in animal foods, such as meat, whereas non-heme iron comes from plants.
Non-heme iron from plant-derived foods is poorly absorbed, while the absorption of heme-iron is efficient. Non-heme iron is also highly affected by phytic acid, whereas heme iron is not (15).
In addition, zinc is well absorbed from meat, even in the presence of phytic acid (16).
As a result, mineral deficiencies caused by phytic acid are rarely a concern among meat eaters.
However, phytic acid can be a significant concern when diets are largely composed of high phytate foods while at the same time low in meat or other animal-derived products.
This is of particular concern in many developing nations where whole grain cereals and legumes are a large part of the diet.
SummaryPhytic acid is usually not a concern in industrialized nations, where food diversity and availability are adequate. However, vegetarians, vegans, and others who eat a lot of high phytate foods may be at risk.
The bottom line
High phytate foods, such as grains, nuts, and legumes, can raise the risk of iron and zinc deficiency.
As a countermeasure, strategies such as soaking, sprouting, and fermentation are often employed.
For those who eat meat regularly, deficiencies caused by phytic acid are not a concern.
On the contrary, consuming high phytate foods as part of a balanced diet has numerous benefits. In most cases, these benefits outweigh any negative effects on mineral absorption.