Phytic acid can impair how the body absorbs some minerals, including iron. It may contribute to deficiencies over time, especially among people following vegetarian or vegan diets.
Phytic acid is a unique natural substance found in plant seeds like almonds, Brazil nuts, walnuts, and wheat bran.
It has received considerable attention due to its effects on mineral absorption. Phytic acid
That’s why it is often referred to as an anti-nutrient. It’s not that simple, though. Phytic acid also has health benefits.
Keep reading to learn about phytic acid, its overall positive and negative effects on health, and how to manage your intake of it.
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.
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
| Food | Amount of phytic acid |
|---|---|
| almonds | 0.4–9.4% |
| beans | 0.6–2.4% |
| Brazil nuts | 0.3–6.3% |
| hazelnuts | 0.2–0.9% |
| lentils | 0.3–1.5% |
| maize, corn | 0.7–2.2% |
| peanuts | 0.2–4.5% |
| peas | 0.2–1.2% |
| rice | 0.1–1.1% |
| rice bran | 2.6–8.7% |
| sesame seeds | 1.4–5.4% |
| soybeans | 1.0–2.2% |
| tofu | 0.1–2.9% |
| walnuts | 0.2–6.7% |
| wheat | 0.4–1.4% |
| wheat bran | 2.1–7.3% |
| wheat germ | 1.1–3.9% |
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.
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.
What are antinutrients?
Antinutrients are compounds in certain plant-based foods that may reduce the body’s absorption of certain minerals when you eat them in the same meal. Usually, you can prepare plant-based foods in a way that reduces how much antinutrients they contain.
Phytic acid isn’t the only antinutrient. Others include:
- lectins
- oxalic acid
- tannins
- protease inhibitors
- saponins
- alkaloids
- goitrogens
- cyanogens
If you eat a well-balanced diet and get enough of key nutrients, you likely won’t have to worry about consuming antinutrients.
However, people with certain health conditions may need to avoid consuming antinutrients in excess or with every meal. For example, if you have hypothyroidism (an underactive thyroid), a doctor may recommend monitoring your intake of goitrogens and cooking goitrogen-containing foods like Brussels sprouts before eating them.
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. Due to their lower cost, people outside of developing countries may also rely on these.
Instead of avoiding these foods, you can try several preparation methods that can significantly reduce the phytic acid content of foods.
Commonly used methods include:
- Soaking: Cereals and legumes are often soaked in water overnight to reduce their phytate content.
- Sprouting: The sprouting of seeds, grains, and legumes, also known as germination, causes phytate breakdown, reducing it by about 60%.
- Fermentation: During fermentation, bacteria produce phytases, which are enzymes that break down phytate. They also activate phytases naturally found in grains by lowering the pH.
- Cooking: Heating cereals and legumes reduces their phytic acid content. For instance, cooking legumes for 1 hour can reduce phytic acid content by up to 80%.
Combining these methods can reduce phytate content substantially.
Phytic acid is a good example of a nutrient that can be both beneficial and harmful, depending on the circumstances.
For most people, it’s a healthy plant compound that serves as an antioxidant and may protect against insulin resistance. Insulin resistance occurs when your muscles, fat, and liver don’t respond as they should to insulin, which can cause glucose levels to increase in your blood. Insulin resistance is associated with type 2 diabetes.
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.
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.
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 absorbed more efficiently. Non-heme iron is also highly affected by phytic acid, whereas heme iron is not.
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.
If you’re concerned about your iron or zinc intake and absorption, it’s best to talk with a healthcare professional, such as a primary care or family doctor.
Routine blood tests ordered during a well-care appointment typically assess your blood for these important nutrients.
If you have a deficiency, doctors may recommend changes to your diet, supplements, or other interventions to increase how much of these nutrients are in your blood.
Symptoms of these nutrient deficiencies can include:
| Zinc deficiency | Iron deficiency |
|---|---|
| unexplained weight loss open sores on the skin or wounds that won’t heal lack of alertness decreased sense of smell and taste diarrhea reduced appetite | fatigue pallor shortness of breath headaches heart palpitations hair, skin, and nail damage mouth sores restless legs |
If you’re experiencing symptoms of a nutrient deficiency, it’s best to talk with a healthcare professional.
Phytic acid is a compound found in seeds that may reduce iron and zinc absorption when consumed with foods containing those minerals. Despite that, it may also have some health benefits and isn’t usually a concern if you get enough of those minerals in your diet.
Foods high in phytic acid include nuts like almonds, Brazil nuts, and walnuts. It can also include grains like wheat and rice bran and seeds like sesame seeds. However, cooking, sprouting, or soaking these foods can reduce their phytic acid content.
However, it may have benefits for your digestive tract, particularly the large intestine (colon). Whole grains, which are typically high in phytic acid, are associated with a reduced risk of colon cancer.
You can usually remove phytic acid from food through cooking and preparation like soaking, boiling, sprouting, or fermenting foods containing it.
High phytate foods, such as grains, nuts, and legumes, can raise the risk of iron and zinc deficiency.
As a countermeasure, strategies such as cooking, 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.