Phytic acid is an antinutrient found exclusively in plant foods. You will be amazed at how many everyday foods contain this substance. The main effect of phytic acid is that it blocks the absorption of minerals, proteins, and digestive enzymes.
In this article, you will learn how much phytate is too much, in which foods you can find phytic acid, and how to neutralize it.
What Is Phytic Acid?
Phytic acid is a compound in high amounts in legumes, whole grains, cereals, and oilseeds.
The critical characteristic of phytic acid is that it can bind minerals and proteins. Because it thereby prevents nutrient absorption, it is also known as an antinutrient.
In nature, phytic acid occurs in the form of phytate. Phytate is the salt of phytic acid, which serves plants as a storage form of phosphorus.
When phytic acid binds to a mineral, phytate is formed.
Phytic Acid in Foods
Phytic acid is found only in foods that come from plants.
Because it is essential for the reproduction and growth of plants, you will find high concentrations in their seeds.
All edible seeds, grains, legumes, and nuts contain phytic acid. Roots and tubers can also contain significant amounts of phytic acid (Gibson et al. 20101).
Is It Bad for You?
Phytic acid prevents the absorption of iron, calcium, magnesium, zinc, and protein (Sarkhel et al. 20222).
Foods with phytic acid reduce the bioavailability of these nutrients from a meal.
For example, if you eat mussels with a lentil salad, the lentils will reduce the body’s absorption of iron from the mussels. However, this effect is not permanent.
If you eat cheese two hours later, the zinc absorption from the cheese is no longer inhibited by the phytic acid from the lentils.
However, a mineral deficiency can develop over time if you consume more significant amounts of phytic acid with each meal.
Because phytate is only found in plants, vegetarians and vegans, in particular, need to watch out for phytic acid in foods.
Studies show that a vegetarian diet can supply just as much iron as a diet containing meat.
However, absorption rates are significantly lower. Women who ate animal products could absorb six times as much iron as those who ate a vegetarian diet for the same absolute iron intake.
Phytic acid is the most significant factor in the reduced bioavailability of iron and zinc from vegetarian diets (Hunt et al. 20033).
In a study of German vegan women under 50, 42% of the participants were iron deficient. The deficiency occurred even though they consumed more than the recommended daily iron requirement from fruits, vegetables, and grain products (Waldmann et al. 20044).
Can Phytic Acid Cause Digestive Problems?
Phytic acid can cause digestive problems, flatulence, and abdominal pain because it inhibits digestive enzymes.
The human gut is not designed to process phytic acid. It passes through our digestive tract and steals minerals on its way to the colon.
Researchers have also found that dietary phytate affects broiler chickens’ gastrointestinal tract and growth regulation (Liu et al. 20095).
Does Phytic Acid Inhibit Iron Absorption?
Yes, phytic acid inhibits the absorption of dietary iron (Gibson et al. 20106).
In addition, studies suggest that high-fiber plants reduce iron absorption in women, while vitamin C may help (Peneau et al. 20087).
Does Phytic Acid Inhibit Calcium Absorption?
Yes, phytic acid reduces calcium absorption (Prynne et al. 20108).
Does Phytic Acid Inhibit Zinc Absorption?
Yes, phytic acid inhibits the absorption of zinc from foods (Gibson et al. 20109).
Symptoms of Too Much Phytic Acid
Bloating and abdominal pain are the first signs of too much phytic acid.
People who suffer from stomach problems, protein deficiency, or mineral deficiencies may want to limit their intake of phytic acid from foods.
Phytic acid forms insoluble compounds with minerals, proteins, enzymes, and starches (Silva et al. 201610).
Because this reduces the daily intake of proteins, iron, magnesium, calcium, and zinc, too much phytic acid in the body can cause the following symptoms (Sarkhel et al. 202211):
- Fatigue and weakness
- Concentration problems
- Decreased immune function
- Skeletal Abnormalities
- Bone loss
- Kwashiorkor syndrome
- Loss of appetite
- Hair loss
- Impotence in men
Because nutrient claims do not correspond to actual intake, I reduce foods with phytic acid.
While Americans consume an average daily intake of 800 mg, most Europeans stay below 400 mg daily (Ellis et al. 198712).
In contrast, people in developing countries who rely on phytate-rich grains and legumes consume up to 2,000 mg per day (Frolich et al. 201913).
If people consume high-quality animal proteins and fats, retinol, vitamin C, D, magnesium, and zinc daily, up to 800 mg of phytic acid daily is safe.
People with mineral deficiencies, gastrointestinal problems, or bone loss should stay below 400 mg daily.
Foods High in Phytic Acid (Table)
Grains, legumes, oilseeds, and nuts are the main foods that bring high amounts of phytic acid into our diet.
In the following tables, you will find these foods high in phytic acid sorted by grams per 100 g dry weight (Gupta et al. 201314):
|Cereals||Phytinsäure g/100 g|
|Legumes||Phytinsäure g/100 g|
|Oilseeds||Phytinsäure g/100 g|
|Nuts||Phytinsäure g/100 g|
How to Reduce Phytic Acid in Foods
The easiest way to reduce the harmful effects of phytic acid is to limit its intake from food.
Unlike many developing countries, we can afford this luxury. Food is often scarce there, forcing people to consume grains and legumes as staples.
Nonetheless, there are also ways to reduce phytate content in foods.
Here are the preparation methods that can partially neutralize phytic acid:
- Soaking: Grains and legumes are often soaked overnight in water to neutralize phytic acid (Petroski et al. 202015). However, the results of this method are not always impactful (Shi et al. 201816).
- Germination: Scientists have successfully reduced phytate levels in beans, barley, and rye through germination (Luo et al. 201217, Centeno et al. 200118).
- Fermentation: organic acids produced during fermentation neutralize phytic acid. For example, prolonged sourdough fermentation can reduce phytates through lactic acid bacteria by up to 90% (Lopez et al. 200119). Similarly, fermentation of soaked whole beans reduced phytic acid by 88% after 48 hours (Gustaffson et al. 199520).
- Cooking: Cooking legumes, except soybeans, can significantly reduce their phytic acid content (Shi et al. 201821). Cooking is also usually even more effective when combined with other methods, such as soaking.
Low Phytic Acid Foods
The best foods without phytic acid are mostly animal-based. There are several reasons for this, mainly related to nutritional deficiencies.
Animal foods such as meat contain heme iron, which is not found in plants.
Non-heme iron from plant foods has low bioavailability, while the body efficiently absorbs heme iron.
The absorption of non-heme iron from plants is strongly limited by phytic acid, whereas this is not the case for heme iron (Peneau et al. 200822).
Furthermore, zinc from meat is well absorbed by the body even in the presence of phytic acid (Sandström et al. 198923).
For this reason, mineral deficiencies caused by phytic acid are rarely a problem in meat eaters.
In contrast, mineral deficiencies are especially problematic in developing countries, where whole grains and legumes comprise a large part of the diet.
Therefore, reducing the consumption of grains, legumes, oilseeds, and nuts makes sense when eating little meat and other animal products.
Good vegetarian options that can replace these phytate-containing foods are cruciferous vegetables, cabbage, and other green vegetables.
Broccoli, cauliflower, asparagus, and celery are comparatively high in nutrients and low in anti-nutrients.
Phytic acid can cause digestive problems. However, phytic acid’s far more problematic effect is that it inhibits mineral absorption. Therefore, it makes sense, especially for vegetarians, to reduce phytate intake in the diet.
Especially cereals, legumes, and oilseeds also contain other antinutrients, such as oxalic acid or lectins, which naturally protect the seeds.
Therefore, I advise avoiding these food groups, especially whole grains.
Another option is to partially neutralize the phytic acid in foods through soaking, sprouting, fermentation, and cooking.
However, phytic acid’s supposedly harmful mineral binding can also have health benefits.
Phytates can also bind and remove toxic minerals from the body. For this reason, phytic acid is used therapeutically to remove uranium (Cebrian et al. 200724).
However, the same ability that enables phytic acid to remove uranium from cancer cells also deprives healthy cells of essential minerals and damages them.
Nevertheless, because of its antioxidant properties, some researchers believe that phytic acid could be used against cancer or cardiovascular disease (Silva et al. 201625).
Inositol hexaphosphate (IP6) from phytates could treat colon cancer, although supporting studies are still lacking (Vucenik et al. 200326).
Frequently Asked Questions
What is phytic acid, and why is it bad?
Phytic acid binds proteins and minerals, such as iron, magnesium, calcium, and zinc, so the body cannot absorb them.
What foods are high in phytic acid?
Legumes, grains, seeds, and nuts are high in phytic acid.
What are the pros and cons of phytic acid?
Phytic acid can cause mineral deficiencies but has antioxidant properties.
What neutralizes phytic acid?
Soaking, germination, fermentation, and cooking reduces phytic acid.
Low and High Oxalate Foods List: Learn which foods are very high in oxalates and how to reduce them with simple methods and a low-oxalate diet.
Why Chia Seeds Are Not Good for You: Although celebrated as a superfood, studies suggest that chia seeds are rather bad than good for you due to their surprising side effects.
Foods High in Lectins and Lectin-Free Food List: Learn about lectins, leaky gut, autoimmune diseases, lectin-free diet, high lectin foods, and how to neutralize them.
Stephan is a writer and a true man of science, holding multiple diplomas and master's degrees in different research areas. His greatest passion is closing the gap between the conventional perception of health and the latest scientific evidence – always following the data.