Nutritional Impact of Phytates

Synopsis By:  Julia Tyack

  1. Definitions – Digestion, Phytic acid, phytase,
  2. Literature reviews

What is digestion:

The human digestive system is a chimera.  It’s one part us, one trillion parts microbes. We supply the long, hollow tube that begins at our mouth and coils for a dozen meters or so inside our abdominal cavity until it ends at the rear. The microbial world populates the tube with enough bacteria and fungi to outnumber our own cells ten to one. 165 The average human colon contains over 800 species of microbiota and at least 7000 different strains. 166   …… Bacteria are capable of transforming indigestible, bland, and even toxic compounds into nourishing and delicious foods. With an arsenal of enzymes, microbes can break down toxins that might otherwise sicken or kill  us outright, turn simple sugars into complex nutrients, make vitamins our diets might otherwise lack (such as K2 and B12) and wage chemical warfare on would-be pathogens. All we do for them is provide a warm place to work and plenty of water.

An action of microbiota in combination with the emzyme Phytase in breaking down phytic acid is but one example of such digestive action.  Yeast and other microbes (such as those in sourdough) contain enzymes (called phytases) that break down phytates in the seed, freeing the zinc, calcium, magnesium and other minerals from their chemical cages.

An illustration of bread dough being better than unleavened dough is in Dr Catherine Shanahan MD’s book.  She tells of poor Turkish families with dwarfed children for whom no defective gene could be identified. The researchers then looked at nutrition.  Tests came up with low levels of nutrients as a possible cause.  The conclusion was that the parents of these children were buying cheaper, unleavened bread and were also unable to afford much meat, a good source of zinc and magnesium.  The unleavened bread was the last straw.  Bound to pytates, the zinc and magnesium in the bread passed through undigested, leading to mineral deficiencies that prevented proper expression of the children’s bone-building genes. 168”   Papers for this research were from Cambridge World Heritage of Food P 1473, and Serum or plasma cartilage oligomeric matrix protein concentration as a diagnostic marker in pseudoachondroplaxia differential diagnosis of a family A Cevik Tufan et al.

Deep Nutrition. Quotes in the book: Why Your Genes Need Traditional Food Catherine Shannahan MD Luke Shanahan

This highlights along with many other studies that grains are better in leavened forms.

Edward Mellanby the discoverer of Vit. D. also showed in his studies that the consumption of high-phytate cereal grain interferes with bone growth and interrupts vitamin D metabolism. High levels of phytic acid in the context of a diet low in calcium and vitamin D resulted in rickets and a severe lack of bone formation.

His studies showed that excessive phytate consumption uses up vitamin D. And conversely that Vitamin D can mitigate the harmful effects of phytates. According to Mellanby, “When the diet is rich in phytate,

perfect bone formation can only be procured if sufficient calcium is added to a diet containing vitamin D.”[Footnote 1]
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What is Phytic Acid:

Phytic acid is an emzyme, protein, anti-nutrient found most commonly in grains, legumes, nuts, and seeds where it is bound tightly with the calcium, magnesium, zinc and iron in your food.  They escort each other through your digestive tract, unabsorbed by your body.  In a study where phytic acid was removed from wheat iron absorption was 12 times increased, Oat Porridge 8 times increased.  Meat in the diet will help you absorb the minerals in your grains and legumes.  The concern is for vegetarians.  Vitamin C will improve your absorption of minerals in a high phytic acid food up to 3 times but without phytates 10 fold Source Hurrell et al., Am J Clin Nutr 77:1215

 Fermentation medium – Kefir is a cultured milk beverage, the result of microbial action of a wide community of microorganisms present in kefir grains on milk. The microorganism are lodged in the grains in a polysaccharide matrix of “kefiran”. The resulting beverage has a uniform creamy consistency, a slightly acidic taste caused mostly by lactic acid, some effervescence due to carbon dioxide and a minute (<2%) concentration of alcohol due to the action of yeast cells also present in the grains. Kefir also contains a variety of aromatic substances which give it a characteristic flavour. Microorganisms present in the grains are called probiotic because they are beneficial to human health.

There are lactobacilli, such as Lb. brevis, Lb. cellobiosus, Lb. acidophilus, Lb. casei, Lb. helveticus, Lb. delbrueckii, Lb. lactis, etc., lactococci, such as different subspecies of Lc. lactisStreptococcus salivarius ssp. thermophilusLeuconostoc mesenteroides and L. cremoris and a variety of yeasts (fungi), such as Kluyveromyces, Candida, Torulopsis, and Saccharomyce

Removing Phytic Acid

Therefore, removal of phosphate residues from phytate results in a reduced impairment of intestinal uptake of essential dietary minerals (13–15). In isolated form only myo-inositol pentakisphosphate suppressed absorption of iron, zinc and calcium in humans, while myo-inositol tetrakis- and trisphosphates had no effect.”

An example of a phytate with no binding effect was found in review of the literature – Coconut flour is reported to have a phytate salt that has no detrimental effect.

 Benefits of Phytic Acid

In the medical literature there are research papers suggesting benefits in phytic acid ingestion.  This paper goes on to report “Phytate benefits: Some of these compounds, in particular D-myo-inositol(1,4,5)trisphosphate  and D-myo-inositol(1,3,4,5)tetrakisphosphate, have been demonstrated to play an important role as intracellular second messengers (16), and several isomers of myo-inositol phosphates have shown important pharmacological effects, such as prevention of diabetes complications and anti-inflammatory effects (51,52) as well as antiangiogenic and antitumour effects (50). In addition,dietary myo-inositol phosphates have been suggested to bring about benefits for human health, such as amelioration of heart disease conditions by controlling hypercholesterolemia and atheriosclerosis (45), prevention of renal stone formation (44), and protection against a variety of cancers, in particular colon cancer (46). “.

GREINER and U. KONIETZNY: Phytase for Food Application, Food Technol. Biotechnol. 44 (2) 125–140 (2006) 135

One of many Pub Med papers on Phytic acid is:

A Pub Med paper – Abstract J Alzheimers Dis 2011;23(1) 21-35 Anekonda TS. WadsworthTL, Sabin R, Frahler K. Harris C, Petriko B, Raile M, Woltjer R, Quinn JF.

Department of neurology, Oregon Health & Science University, Portland, OR.  97239. USA

We propose a novel protective treatment for AD pathology with phytic acid (inositol hexakisphosphate).


These results suggest that phytic acid may provide a viable treatment option for AD.  It seems by other research papers that this benefit is a complex laboratory sequencing of target proteins and may not be as simple as consuming phytic acid.

“20. A fusion protein comprising: (a) a first polypeptide; and (b) a second polypeptide fused to the C-terminus of the first peptide, wherein the first polypeptide is heterologous with respect to the second polypeptide, the second polypeptide has an amino acid sequence that is at least 95% identical to SEQ ID NO:17, and the second polypeptide has cysteine protease activity when induced by inositol hexakisphosphate such that the second polypeptide is cleaved.”

Living with Phytic Acid – by Ramiel Nagel March 16 2010

“Phytic acid is the principal storage form of phosphorus in many plant tissues, especially the bran portion of grains and other seeds.  It contains the mineral phosphorus tightly bound in a snowflake-like molecule.  In humans and animals with one stomach, the phosphorus is not readily bioavailable.  In addition to blocking phosphorus availability, the “arms” of the phytic acid molecule readily bind with other minerals, such as calcium, magnesium, iron and zinc, making them unavailable as well.  In this form, the compound is referred to as phytate.  Phytic acid not only grabs on to or chelates important minerals, but also inhibits enzymes that we need to digest our food, including pepsin,1 needed for the breakdown of proteins in the stomach, and amylase,2 needed for the breakdown of starch into sugar.  Trypsin, needed for protein digestion in the small intestine, is also inhibited by phytates.   Phytic acid is the principal storage form of phosphorus in many plant tissues, especially the bran portion of grains and other seeds. It contains the mineral phosphorus tightly bound in a snowflake-like molecule.

Conclusion:  That phytate has detrimental effects resulting in mineral deficiencies, in populations where cereal grains provide a major source of food.  In these communities osteoporosis and even rickets are common.

A number of papers also pose the question as to whether phytate in inhibiting protein digestion play a role in allergies. This is a interesting research question.  It is thought that in the case of a

compromised intestinal brush boarder that larger undigested protein escape into the blood stream causing immune reaction.

What is Phytase:

Phytase is the enzyme that neutralizes phytic acid and liberates the phosphorus. This enzyme co-exists in some plant foods that contain phytic acid.
“In general, humans do not produce enough phytase to safely consume large quantities of high-phytate foods on a regular basis.  However, probiotic lactobacilli, and other species of endogenous digestive microflora can produce phytase.  27 Thus, Humans who have good intestinal flora will have an easier time with foods containing phytic acid. Increased production of phytase by the gut microflora explains why some volunteers can adjust to a high-phytate diet.  Sprouting activates phytase, thus reducing phytic acid. 28 Soaking grains and flour in an acid medium at very warm temperatures, as in the sourdough process, also activates phytase and reduces or even eliminates phytic acid.”  Living with Phytic Acid. Ramiel Nagel. March 26 2010.”

“Furthermore, it was demonstrated that only a very low phytate-degrading activity occurs in the human small intestine (27). Thus, the human small intestine has only very limited ability to hydrolyse phytate.  Dietary phytases, in contrast, are an important factor for phytate degradation In oriental food fermentation, however, convincing evidence exists that phytases of the microorganisms used for fermentation contribute significantly to phytate degradation.

R. GREINER and U. KONIETZNY: Phytase for Food Application, Food Technol. Biotechnol. 44 (2) 125–140 (2006) 135”

Pub Med has listed a number of animal studies.  Monostomach animals and humans have little or no phytase naturally in their guts.  Producing mono-stomach  livestock on increased grain consumption in recent years was producing inferior smaller animals.  It is now a popular practice to add commercial phytase to the grains and this produces a stronger, larger animal faster.

Reducing Phytic Acid

 Whole grains such as wheat, rye and buckwheat are potent sources of phytase “The phytase activity of grains and seeds varied over a wide range …and the most potent sources of phytase were rye, wheat and buckwheat” (Egli 2001). (Liu, Wang et al. 2007), and when these grains are added to other cereals complete degradation of phytates occurred in 1 – 2 hours!

  • “By adding 10% whole wheat, whole rye or whole buckwheat to complementary foods (e.g., wheat and soy, millet and cowpea, and rice and chickpea foods) it was possible to degrade phytic acid completely in 1–2 h by holding the mixture in aqueous solution at the optimum pH of the phytase”(Egli, 2001).
  • Soaking mixed grains and ensuring grains with high phytase activity are also included, will enable phytase to release bound minerals trapped in the grain matrix.
  • The optimum pH for phytase in the dissertation by Egli et al was between 5.0 – 5.5 i.e. an acidic pH. This is why yoghurt, kefir, sour apples*, berries* or lemon juice* added to the muesli mix and soaked overnight helps to activate the phytase. “From website NutriDesk.

“One ideal phytase for all food applications does not exist.  Thus, screening nature for phytases with more favourable properties for food applications and engineering phytases in order to optimise their catalytic and stability features are suitable approaches to make a proper phytase available for a specific application in food processing.  The phytases may be used in isolated form or produced in high levels in recombinant microorganisms”

Introducing an exogenous phytase into the production process, however, was reported to result in significantly higher protein yields and an almost complete removal of myo-inositolhexakis-, pentakis-tetrakis-, and trisphosphates from the final plant protein isolate (19,20) . Due to an improvement in mineral bioavailability, their amino acid composition as well as their in vitro protein digestibility, these phytate-reduced plant protein isolates were suggested as suitable protein sources for infant formulae. In addition, some phytate–reduced plant protein isolates are discussed as functional additives in food products, because of their good foaming, emulsifying and gelling properties.

Microorganisms used for food fermentation such as Saccharomyces cerevisiaeLactobacillussanfranciscensis or Lactobacillus plantarum there is no need for protein purification. Application of microorganisms improved in such a way in fermentation of plant-derived raw material is expected to result in food products with significantly lower phytate levels.

In oriental food fermentation, however, convincing evidence exists that phytases of the microorganisms used for fermentation contribute significantly to phytate degradation.  Phytate as an antinutrient Phytate behaves in a broad pH range is a highly negatively charged ion and has therefore a tremendous affinity for food components with positive harge(s), such as minerals, trace elements and proteins (11,26).

Nutritional Impact of Phytates


“Salts of phytic acid, designated as phytates, are regarded as the primary storage form of both phosphate and inositol in plant seeds and grains.  Phytate is formed during maturation of the plant seed and in dormant seeds it represents 60–90 % of the total phosphate (24).  Phytate is therefore a common constituent of plant-derived

foods (Table 1).  Depending on the amount of plant–derived foods in the diet and the grade of food processing, the daily intake of phytate can be as high as 4500 mg (25). On average, daily intake of phytate was estimated to be 2000–2600 mg for vegetarian diets as well as diets of inhabitants of rural areas in developing countries

and 150–1400 mg for mixed diets (25).”

R. GREINER and U. KONIETZNY: Phytase for Food Application, Food Technol. Biotechnol. 44 (2) 125–140 (2006) 135

Table 5. Myo-inositol phosphate intermediates generated through enzymatic phytate degradation

Enzyme IP5-isomer IP4-isomer IP3-isomer IP2-isomer IP-isomer Reference


 Phytates in small amounts show some health benefits.  Phytates in excessive amounts deplete the body of both mineral, vitamin and protein utilization.

Ancient grain methods of processing helped to removed phyates.  It is postulated that organic grains such as oats grown without phosphate fertilizers contain less phytates – some oatmeal depending on growing methods is as low as .89 but the average is 2.40  as a percentage of dried weight.  There is varying opinions on how much phytate is reduced by soaking a grain low in phytase like rice or oats.  There is consensus that warm soaking, with a catalyst like Kefir and the addition of a plant phytase such as buckwheat will remove most of the phytate.. Also adding acid to the water such as lemon juice or vinegar increases the phytic acid degradation.

Rye is the best grain of all when used for bread made with sour dough.

Yeast or sour dough raised breads should be eaten and unleaven breads unless fermented avoided.

Some seeds and nuts are much higher in phytates than grains – sesame being the highest.  Also other substances such as coffee, cocoa are high in phytates. Tea is also listed as a problem because of binding with the tannin.

Also another good link