Phytic acid is a unique natural substance found in plant seeds.
It has received considerable attention due to its effects on the absorption of minerals.
Phytic acid impairs the absorption of iron, zinc and calcium and can promote mineral deficiencies (1).
Therefore, it is often referred to as an anti-nutrient.
However, the story is a bit more complicated because phytic acid also has several health benefits.
This article analyzes phytic acid in detail and its general effects on health.
Phytic acid, or phytate, is found in the seeds of plants. It serves as the main storage form of phosphorus in the seeds.
When the seeds sprout, the phytate degrades and the phosphorus is released to be used by the young plant.
Phytic acid is also known as inositol hexaphosphate, or IP6.
It is often used commercially as a preservative due to its antioxidant properties.
Summary Phytic acid is found in plant seeds, where it functions as the main form of phosphorus storage.
Phytic acid in food
Phytic acid is only found in foods derived from plants.
All seeds, grains, legumes and edible nuts contain it in varying amounts, and small quantities are also found in the roots and tubers.
The following table shows the amount contained in some foods with high phytate content, as a percentage of dry weight (1):
As you can see, the phytic acid content is very variable. For example, the amount contained in the almonds can vary up to 20 times.
Summary Phytic acid is found in all seeds of plants, nuts, legumes and grains. The amount contained in these foods is very variable.
Phytic acid impairs the absorption of minerals
Phytic acid impairs the absorption of iron and zinc, and to a lesser extent calcium (2, 3).
This applies to a single meal, not to the general absorption of nutrients throughout the day.
In other words, phytic acid reduces the absorption of minerals during food, but has no effect on subsequent meals.
For example, snacking nuts between meals may reduce the amount of iron, zinc, and calcium you absorb from these nuts, but not from the food you eat a few hours later.
However, when you consume phytate-rich 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 they can be a major problem during periods of malnutrition and in developing countries where cereals or legumes are the main source of food.
Summary Phytic acid impairs the absorption of iron, zinc and calcium. Over time, it can contribute to mineral deficiencies, but this is rarely a problem for those who follow well-balanced diets.
How to reduce phytic acid in food?
Avoiding all foods that contain phytic acid is a bad idea because many of them are healthy and nutritious.
In addition, in many developing countries, food is scarce and people need to rely on cereals and pulses as their main staples.
Fortunately, several methods of preparation can significantly reduce the phytic acid content of foods.
These are the most used methods:
- Soaking: Cereals and legumes are often soaked in water overnight to reduce their phytate content (1, 4).
- Sprouting: The sprouting of seeds, grains and legumes, also known as germination, causes the degradation of phytate (5, 6).
- Fermentation: Organic acids, formed during fermentation, promote the decomposition of phytate. Fermentation with lactic acid is the preferred method, a good example of this is the production of fermented dough (7, 8).
The combination of these methods can substantially reduce the phytate content.
For example, soaking, sprouting and fermenting with lactic acid can reduce the phytic acid content of quinoa seeds by 98% (9).
In addition, sprouting and fermentation with lactic acid from white sorghum and maize can almost completely degrade phytic acid (10).
Summary Various 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 good and bad, depending on the circumstances.
For most people, it is a compound of healthy plants. Phytic acid is not only an antioxidant, it can also protect against kidney stones and cancer (11, 12, 13, 14).
Scientists have even suggested that phytic acid may be part of the reason why whole grains have been linked to a reduced risk of colon cancer (15).
Summary Phytic acid can have several positive health effects, such as protection against kidney stones and cancer.
Is phytic acid a health problem?
Phytic acid is not a health problem for those who follow a balanced diet.
However, those at risk of iron or zinc deficiency should diversify their diets and not include foods high in phytate at all meals.
This can be especially important for those with iron deficiency, as well as for vegetarians and vegans (2, 16, 17).
There are two types of iron in food: heme iron and non-heme iron.
Heme iron is found in foods of animal origin, such as meat, while non-heme iron comes from plants.
The non-heme iron in plant-derived foods is poorly absorbed, while the absorption of heme iron is efficient. Non-heme iron is also greatly affected by phytic acid, whereas heme iron is not (18).
In addition, zinc is well absorbed from meat, even in the presence of phytic acid (19).
Therefore, mineral deficiencies caused by phytic acid are rarely a concern among meat consumers.
However, phytic acid can be a major problem when diets are largely composed of phytate-rich foods and, at the same time, low in meat or other animal products.
This is especially worrying in many developing nations where whole grains and legumes are a big part of the diet.
Summary Phytic acid is generally not a concern in industrialized nations, where the diversity and availability of food is adequate. However, vegetarians, vegans and others who eat many foods high in phytates may be at risk.
The bottom line
Foods rich in phytates, such as grains, nuts and legumes, can increase 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.
Conversely, the consumption of phytate-rich foods as part of a balanced diet has numerous benefits.
In most cases, these benefits outweigh any negative effects on mineral absorption.
Reference: https: //www.healthline.com/nutrition/phytic-acid-101