Wednesday, October 19, 2011

Phytate Facts

Concerned about phytates in seed foods (nuts, seeds, grains, legumes) blocking mineral absorption and causing ill health?

You can relax.  Context matters. 

Consuming foods rich in ascorbate (vitamin C) with foods rich in phytate can cancel the negative effects of phytate on mineral absorption.[1, pdf]  Just eat some fruits and vegetables with foods that supply phytate.

Some studies have shown substantial degradation of phytate in the human gut (70-86%), indicating that humans adapt to diets high in phytate by increasing small intestinal production of phytase. [2 full text link, 3]

I have never seen any evidence that dietary phytate causes mineral deficiencies except in the context of overall poor quality diet, such as people attempting to live on diets composed entirely of unleavened grains and legume flours without adequate intake of vegetables, fruits, and other mineral sources.

If you live in a modern industrialized nation, when was the last time you had someone tell you that a physician diagnosed her with multiple mineral deficiencies caused by excessive dietary phytate?

I have never seen it.

Anticancer Effects of Phytates

Everything has a front and a back.

According to researchers from Linus Pauling Institute of Science and Medicine, phytates appear to have anticancer effects by binding excess minerals in tissues, depriving tumors of essential minerals.[4 pdf]

Vucenik and Shamsuddin discuss the anticancer properties of phytate in detail; all information and quotes remaining in this post come from their report in the Journal of Nutrition.[5 full text]

Almost all mammalian cells contain phytate in the inositol hexaphosphate (IP6) form and others with smaller numbers of phosphate groups (IP1-5).  When we ingest dietary phytate, intracellular levels of IP6 increase, and from this cells increase the levels of the other forms, which appear involved in "cellular signal transduction, regulation of cell function, growth, and differentiation."

Dietary phytate enters the blood stream and reaches tissues, including tumors, far from the gut.

Tumor cells take up phytate, probably by pinocytosis or receptor-mediated endocytosis.

Phytate inhibits malignant growth in human leukemic, colon cancer, breast cancer, cervical cancer, prostate cancer, and liver cancer cells.

"IP6 inhibited the growth of all tested cell lines in a dose- and time-dependent manner. The growth of cells of hematopoietic lineage was inhibited: human leukemic hematopoietic cell lines, such as K-562 (26,27) and human normal and leukemic hematopoietic cells (27). The antiproliferative activity of IP6 was further reported in human colon cancer HT-29 cells (28), estrogen receptor–positive and estrogen receptor–negative human breast cancer cells (32), cervical cancer (25), prostate cancer (15,33,34), and HepG2 hepatoma cell lines (31). IP6 also inhibited the growth of mesenchymal tumors, murine fibrosarcoma (39), and human rhabdomyosarcoma (38)."
Phytate also causes malignant cells to mature and differentiate into normal cells:
"The potential of IP6 to induce differentiation and maturation of malignant cells, often resulting in reversion to the normal phenotype, was first demonstrated in K-562 hematopoietic cells (26). IP6 was further shown to increase differentiation of human colon carcinoma HT-29 cells (28,29), prostate cancer cells (33), breast cancer cells (32), and rhabdomyosarcoma cells (38)."
Phytates provide an intracellular antioxidant function by binding with iron, which suppresses formation of the most hazardous hydroxyl radicals:
"The antioxidant role of IP6 is known and widely accepted; this function of IP6 occurs by chelation of Fe3+ and suppression of ·OH formation (11). Therefore, IP6 can reduce carcinogenesis mediated by active oxygen species and cell injury via its antioxidative function."
Phytate also stimulates the immune response and protects against carcinogen-induced depression of natural killer cell activity.
"Besides affecting tumor cells, IP6 can act on a host by restoring its immune system. IP6 augments natural killer cell activity in vitro and normalizes the carcinogen-induced depression of natural killer cell activity in vivo (59). "
Phytate only adversely affects malignant cells, not normal cells:
" The most important expectation of a good anticancer agent is for it to only affect malignant cells and not affect normal cells and tissues. That property was recently shown for IP6. When the fresh CD34+ cells from bone marrow was treated with different doses of IP6, a toxic effect (inhibition of the clonogenic growth or as cytotoxicity on liquid cultures) was observed that was specific to leukemic progenitors from chronic myelogenous leukemia patients but no cytotoxic or cytostatic effect was observed on normal bone marrow progenitor cells under the same conditions."
 This indicates that normal cells are adapted to phytate.  Of course, since phytate is abundant in the plant world and also present in almost every mammalian cell.

Phytate inhibits all of the several pathways supporting malignancy:
" From the behavior and characteristics of malignant cells, several principal pathways of malignancy have been established, such as proliferation, cell cycle progression, metastases and invasion, angiogenesis, and apoptosis; interestingly, IP6 targets and acts on all of them."
 In one pilot clinical trial, six patients with advanced colorectal cancer (Dukes C and D) with multiple liver and lung metastasis received oral phytate plus chemotherapy.  One of the patients refused additional chemotherapy after one session and she was treated only with IP6 plus inositol.  What happened?

"...her control ultrasound and abdominal computed tomography scan 14 mo after surgery showed a significantly reduced growth rate. A reduced tumor growth rate was noticed overall and in some cases a regression of lesions was noted."
Say again?  A simple, natural dietary ingredient reversed the progress of cancer!

Which reminds me:
"Pioneering experiments showing this novel anticancer feature of IP6 were performed by Shamsuddin et al. (1820), who were intrigued by the epidemiologic data indicating that only diets containing a high IP6 content (cereals and legumes) showed a negative correlation with colon cancer." 
Most hunter-gatherer groups would have consumed significant phytate from nuts and seeds of various sorts, including legumes.

Dietary Phytate Safety
Vucenik and Shamsuddin agree that chronic phytate ingestion does not cause mineral deficiencies whether gotten from food or isolated form unless the overall diet lacks essential minerals:

"Some concerns have been expressed regarding the mineral deficiency that results from an intake of foods high in IP6 that might reduce the bioavailability of dietary minerals. However, recent studies demonstrate that this antinutrient effect of IP6 can be manifested only when large quantities of IP6 are consumed in combination with a diet poor in oligoelements (6063). A long-term intake of IP6 in food (60,61) or in a pure form (64) did not cause such a deficiency in humans. Studies in experimental animals showed no significant toxic effects on body weight, serum, or bone minerals (Table 5) or any pathological changes in either male F344 or female Sprague-Dawley rats for 40 wk (40,51,52). Grases et al. (65) confirmed our findings and also reported that abnormal calcification was prevented in rats given IP6."
 Phytate has many benefits:  
"In humans, IP6 not only has almost no toxic effects, but it has many other beneficial health effects such as inhibition of kidney stone formation and reduction in risk of developing cardiovascular disease. IP6 was administered orally either as the pure sodium salt or in a diet to reduce hypercalciuria and to prevent formation of kidney stones, and no evidence of toxicity was reported (64,65,79,80). A potential hypocholesterolemic effect of IP6 may be very significant in the clinical management of hyperlipidemia and diabetes (75,76,81). IP6 inhibits agonist-induced platelet aggregation (82) and efficiently protects myocardium from ischemic damage and reperfusion injury (83), both of which are important for the management of cardiovascular diseases. "
Perhaps avoiding and removing phytates from food doesn't serve your best interests?

Perhaps we evolved to consume significant amounts of phytates, and cancer is a disease facilitated by a dietary deficiency of phytates?


Chuck said...

are you saying the rise in cancer instances may have to do with phytate deficiency?

Izaak Miller said...

Thank you, I've been waiting for something like this.

Don said...


I believe it is possible, i.e. a hypothesis, that the reduction of phytate in our diets by food refining and reduced consumption of phytate-rich foods has been one reason for the rise in cancer incidence in industrialized nations since the industrial revolution.

Anonymous said...

"when was the last time you had someone tell you that a physician diagnosed her with multiple mineral deficiencies caused by excessive dietary phytate?"

This isn't because phytates don't cause mineral deficiencies, but because we've responded to a long history of phytate induced problems by enriching grains, processing them different, or diversifying our diet. Pellagra (B3 deficiency) is a common example and is still widely suffered by poor people around the world whom eat too much non-nixtamalized corn.

Eric said...

I've read and come upon such info in the past Don, from various sources; you put it in one easily assimilable article very succintly!!!

What should we make then of all the various and tedious traditional preparation methods for grains and legumes then? Many, not the least of which is the WAPF, advocate for such traditional preparation of grains, in spite of an otherwise nutrient-dense nutritional approach...

Or how about the maybe ill-advised encouragement to, if one chooses to eat them, eat the more refined versions of certain foods (ex: white rice instead of brown (I'm thinking the Jaminet's PHD here), or white bread over whole-grain varieties (Anthony Colpo's latest post mentions this...).

Don said...


Phytates don't affect B-vitamins.

People get pellagra from "too much" corn only when there are no other sources of B3 in the diet and the diet becomes reduced to little more than corn. In other words, they have a limited diet...that's the problem, not the unprocessed corn. Diversification is necessary for nutritional adequacy anyways.


I don't think it is necessary to go to great lengths to attempt to remove phytates from foods UNLESS you have a very limited diet (only grains and legumes) lacking other sources of minerals and vitamin C. But then you might also get scurvy, even if you succeed in removing the phytates.

SoccerGuro said...


How about people with potential gut issues? I attempted to introduce lentils into my diet and my joints have been hurting terribly for the last few days. Do you think the lectins in the lentils are playing any sort of role here?

I would love your input, and maybe in the future you could maybe talk a little more about leaky gut, it's cause and your ideas on how to cure it. The general consensus is no legumes, dairy, eggs, and nightshades.

SoccerGuro said...

How about people with a leaky gut? I attempted to introduce lentils into my diet and my joints have been feeling achy the last couple days. The general consensus is that anyone with gut problems should eliminate legumes, eggs, dairy, grains, and nightshades. I would love to hear your thoughts.

Tomas said...

Mr. Matesz,

Chris Kresser argues that phytic acid messes with digastive enzymes, including pepsin, amylase and trypsin. any thoughts on that?

Don said...


I know of no evidence that phytate impairs digestive enzymes. I welcome any references showing this to be the case.

As I noted in the article, trials appear to have shown no toxic effects of phytates in well nourished individuals. If phytate blocked enzymes, then animals fed large amounts should fail to gain or maintain bodyweight. This appears not to be the case.

In the research cited by Vucenik and Shamsuddin, animals fed high amounts of phytate actually had somewhat higher bone mineral content than controls fed only tap water.


If lentils bother you don't eat them.

I certainly agree that anyone with gut problems should avoid dairy and eggs. Otherwise it is an individual thing.

Ed said...


Are you able to tie together these ideas with historic food preparation techniques? My limited reading on the subject indicates that humans developed preparation techniques to decrease phytates.

Green beans, edible raw or cooked, have minimal phytates.

When grains became a meaningful constituent of diet, they were soaked and fermented as part of processing, reducing phytates.

I'm quite ignorant of legume processing and consumption. Given other anti-nutrients (trypsin inhibitors, etc) my presumption is that they require processing (soaking, sprouting) in order to successfully be used as a staple. This ought to serve to reduce phytates.

I've read stories of processing techniques of nuts to make them more digestible. Soaking, burying (fermenting), roasting, drying, etc.

Without refridgerators, I presume that anti-nutrients like phytates will always be challenged in storage. Everything from bacteria to sprouting will be trying to wrestle free minerals from the nut or seed.

I always feel that discussing the nutrient composition of raw ingredients is only half of the reality. Humans have been processing food through accidental and purposeful processes for hundreds of thousands of years. Our short guts are evidence of our adaptation to easier access to nutrients. I would appreciate and enjoy if you could tie in historical processing techniques along with discussion of foodstuffs.

lightcan said...

Hi Don,

I watched a program on the Hadza. They seem to have a limited diet, consisting of tubers, meat, some fruit and honey. Do they get all the nutrients they need?
So, are you saying that consuming enough fruits and vegetables during the day is going to prevent mineral deficiencies due to phytate binding to them? Would eating nuts on their own help also?

Tomas said...

Well I am not an expert, but a few minutes of pubmeding lead me to this:

Most proteins dissolved almost completely at pH 2, but not after addition of phytate. Phytase prevented precipitation of protein with phytate. Pepsin could release protein from a precipitate, but the rate of release was increased by phytase.

I guess that the "animals fed large amounts" you mention were rats, who express like 30-times more phytase activity than humans

I have no access to this
Use of phytic acid for the determination of pepsin activity in gastric juice
but the title may suggest there's a negative correlation between phytic acid and pepsin activity

majkinetor said...

Thx for the article. Finally some sanity. I posted similar take on Kresser's site:

Don said...


At the beginning of the abstract you cited:

"The interaction between protein and phytate was investigated in vitro..."

In vitro is interesting but I am mostly interested in what happens in living humans.

I will requote the source I quoted:

"...recent studies demonstrate that this antinutrient effect of IP6 can be manifested only when large quantities of IP6 are consumed in combination with a diet poor in oligoelements (60–63). A long-term intake of IP6 in food (60,61) or in a pure form (64) did not cause such a deficiency in humans."

Thus human studies do not support the idea that dietary phytate causes nutrient deficiencies in humans provided that the diet supplies a variety of foods and adequate minerals.

Even if phytate does reduce the rate of digestion of protein in vivo, as possibly suggested by the study you cited, this doesn't mean that phytate consumed in typical amounts from whole foods blocks the digestion of protein and causes protein deficiencies. In fact the study you cited states that phytate slowed the action of pepsin, but did not stop it. A slowing of the process may not have any material effect on overall digestive efficiency at all.

I also cited two human studies that suggest that 70-86% of phytate is degraded in the human gut adapted to phytate ingestion over time. So I wasn't talking only about rats.

Upon realizing that phytate occurs in almost every mammalian cell, it seems difficult to maintain the idea that it is a poison.

Don said...


I haven't analyzed the Hadza diet so I don't know the answer to that question.

I am saying that eating foods rich in vitamin C counteracts the mineral-binding effect of phytates. Another example of how context determines the effect of a dietary compound.

If you eat foods rich in vitamin C (fruits or vegetables) with your nuts, this will counter the mineral-binding effects of the phytate.

Don said...


The people who developed food processing techniques didn't even know that phytates existed, so they couldn't have developed the techniques for that purpose.

I think most historic food prep techniques were developed for flavor and preservation, in absence of refrigeration, not nutritional enhancement.

People soaked or fermented grains because when you soak them they become sweeter and when you leave them longer they ferment, which makes them softer or allows you to produce a leavened bread. People developed picking as a way of food preservation, not a method to increase dietary lactic acid bacteria.

lightcan said...

OK, Don, thank you.

Ezer said...

I never have been concerned about phytates, but the fact that a mineral deficiency was not identified doesn't mean that the level of minerals is adequate. I can testify that, though my diet wasn't bad, supplementing with magnesium had a big positive effect on me.

Steve said...

You state that "...humans adapt to diets high in phytate by increasing small intestinal production of phytase." However, other sites state that this isn't possible for us to produce in our guts: "Non-ruminants like human beings, dogs, birds, etc. do not produce phytase." ( Which is right? Thanks!

Dan Lundeen said...

Don, I recently saw there was some work linking phytate deficiency to osteoporosis, apparently the phytates inhibit the bone-eating things. Didn't see it mentioned here, could be time for you to update your post :-)

Don said...


I addressed that in a new post:


"Phytase activity was found in human small intestine at low values (30 times less than that in rat tissue and 1000-fold lower than alkaline phosphatase in the same tissue)."

So humans produce phytase. Although in this study the level of production was much smaller than that of the rat, biological systems often increase production of enzymes in response to challenges. IOW, the level of production observed would vary according to the level of phytates in the diet of the tested individual.