Is there any danger of phytic acid in food?

Often compared with oxalates, phytates are organic molecules mainly present in the husks of cereals, seeds and even legumes. Produced by the plant from phytic acidthey serve above all as phosphorus reserve. Stored in seeds, they play a key role during germination, providing the nutrients necessary for the development of the young plant.

Less known than other micronutrients, phytic acid is nevertheless widely present in our daily diet. Although it is often described as “d’anti-nutrition”, this is because of its particular chemical structure, which allows it to bind to several essential minerals, such as iron, zinc, calcium or magnesium.

This is the common point they have with oxalic acidwhich also binds to certain minerals to form oxalates.

This ability to reduce the absorption of minerals can be problematic but only in contexts where the diet relies heavily on minimally processed grains or legumesand where mineral intakes are already limited.

Furthermore, this notion of anti-nutrient alone does not summarize the overall role of phytic acid in the diet. Its impact largely depends on the balance of the diet, food preparation methods and individual needs.

So, rather than considering it as a compound to avoid, it is more accurate to see it as an element with which the organism interactsin a balancing act specific to any plant-based diet.

Although they suffer from a rather bad reputation, phytates also have nutritional benefits which deserve to be remembered and highlighted.

Another advantage: unlike oxalic acid, phytic acid appears to play a protective role on the formation of kidney stones. « He tends to inhibit the formation of salt crystals of calcium and to limit their precipitation. This effect is particularly interesting in people with a history of stonesfor which they could help reduce the risk of recurrence » adds Dr. Martinat.

Metabolically, phytates also influence the digestion of carbohydrates. « They act in slowing the action of certain digestive enzymesthus helping to modulate glucose absorption and reduce blood sugar response » continues the specialist. Result: a more progressive glycemic response, with attenuated insulin peaks. This effect could also contribute to the prevention of chronic inflammation.

Finally, some research explores their potential role in the prevention of certain cancers, particularly that of the colon. “Data on the subject are still under investigation, and it is sometimes difficult to distinguish the specific effect of phytic acid from that of foods which contain it, themselves rich in fiber and protective compounds against colorectal cancers” puts Dr. Martinat into perspective.
Nevertheless, all these avenues reinforce the idea that phytates cannot be reduced to their sole anti-nutrient status.

Phytic acid is not dangerous in itself, as it is not toxic to the body.
The main risk of excess phytate-rich foods is exposure to deficiencies due to its high chelating capacity.

Some work also shows that phytates can interfere with the activity of certain digestive enzymes naturally produced by the body. “This is particularly the case of the trypsinea key enzyme in protein digestionoramylaseinvolved in the breakdown of carbohydrates. By binding to these enzymes or modifying their environment of action, phytates can reduce their effectiveness and make digestion more difficult and less complete,” underlines the specialist.

But here again, the impact of phytates depends a lot on the overall dietary context.

Phytates are very widely present in plant-based foodsparticularly in the parts which serve as a reserve for the plant.
“The foods that contain the most are generally the seeds et whole grains (brown or black rice, wholemeal pasta), because phytic acid is stored in bran and germ » indicates the micronutritionist doctor. wheat branfor example, is one of the foods that is most concentrated.
Other foods rich in phytic acid include certain seeds like the sesame, sunflower or flaxTHE nuts (almonds, walnuts, hazelnuts) and legumes (lentils, chickpeas, red beans).

All cereals that have been refined or processed, such as white flour, white rice or highly processed cereal products, on the other hand, are very poor.
Fresh fruits and vegetables also contain very little, and animal foods (meat, eggs, fish, dairy products), are practically deprived.

Good news for people at risk of deficiencies and fans of foods rich in phytic acids (whole grains, legumes or seeds, nuts): several cooking tips allow you to limit harm.

« No soaking first of all, it activates an enzyme called phytase which breaks down phytates to release minerals » explains the expert.
In practice, it takes at least 8 to 12 hours – or overnight – for soaking to begin to have a significant effect on legumes.
For a more pronounced effect, particularly with oilseeds, nuts or whole grains, you can go up to 12 to 24 hours, sometimes with a change of water during soaking. This allows both dissolve part of the phytates (which pass into water) and prolong enzymatic activation.

« The germination (seeds) and fermentation (sourdough bread for example) are two other processes which greatly reduce the phytate content of foods » continues Dr. Martinat.

In the case of the germinationthe young plant needs to mobilize its nutrient reserves, in particular phosphorus stored in the form of phytic acid. It then activates specific enzymes, called phytaseswho go degrade this phytic acid into simpler compounds, usable for its growth.

The fermentation relies on another mechanism, just as effective. It involves micro-organisms – bacteria or yeast – which also produce phytases. By developing in the food, these microorganisms will degrade part of the phytic acid, thus reducing its content.

Last “anti-phytate” tip: consume foods rich in vitamin C within the same meal. « This vitamin acts by limiting the fixation of minerals, in particular iron, and by facilitating its intestinal absorption » explains the specialist.
For this reason, the combination of foods rich in vitamin C — such as citrus fruits, peppers or parsley — with plant sources of iron is often recommended, especially for vegetarians, who are more at risk of deficiency.

“But what we must remember above all is that phytates should not be trackedbecause the foods which are richest in them are also foods very rich in minerals and with many nutritional qualities ! As always, the ideal is to vary your foods to limit excesses and cover all your needs,” concludes Dr. Martinant.