I would love to camp out a little more in the history of fermenting grains and legumes, but since I have a lot of information to get through, I thought today I should start addressing the topic of phytic acid in grains and legumes. This is what the majority of scientific studies I’ve read have been addressing. I haven’t found studies to answer all of my questions yet, but there are certainly a glut of studies to read!
Before I start discussing some of the following information, I wanted to make a few points about the research.
1) There are many studies, and I certainly haven’t read them all. I’ve probably read summaries of 50 +, but there are a lot more. There are some studies (like always) whose findings contradict another study. For this reason, I’ve found it helpful to read a wide variety of studies to find out what the majority of the studies found.
2) As I’ve read different articles on this topic, both the excellent recent one in the Wise Traditions journal and other blogger’s summaries, I’ve realized how their summary is effected by what studies they reference. I am sure that my research will be presented the same way. None of our research is probably going to be telling the whole story, just because there is a lot of information out there, and a lot that truthfully hasn’t been researched yet. Just to give you an idea of how much information there is out there, this topic has been researched for the last 50 years or so, and there are new studies being released on the topic every year!
3) There is some limitation in only reading summaries of studies, as most of us have been doing. However, it has been hard to impossible for me to get my hands on the full study information. I’ve found some summaries to be very detailed and give a lot of information. Others give such a brief summary, that if it conflicts with other studies you have very little to go on in finding out what they did differently.
One of the reasons I am so interested in the history of fermenting grains is because there aren’t clear cut answers for many of my own personal questions on this topic. But since there is a lot out there that is helpful, let’s get started!
Let’s start with the basics.
What is phytic acid (or phytate)?
Phytic acid is tightly bound in the phosphorus content of grains and legumes, especially the bran portion of grain or the outer layer of legumes. It is considered the “principle storage form of phoshorus.”[i]
What’s the big deal?
Phytic acid is well documented to block absorption of not only of phosphorus, but also other minerals such as calcium, magnesium, iron and zinc. [ii] It also negatively affects the absorption of lipids and protein.[iii] I would guess that one reason this is true is because phytic acid also inhibits enzymes that we need to digest our food such as pepsin (which helps break down protein), amylases (convert starch into sugar for digestion) and trypsin (also used in protein digestion). [iv] While whole grains have a much higher mineral content than processed grains, we won’t get the full benefit of that nutrition if phytic acid blocks us from absorbing it.
Phytate has been labeled by the World Health Organization as one of the main causes of anaemia (iron deficiency), a common problem in many countries. [v] Because this is well documented and better nutrition is desired especially for those who depend on grains and legumes for a large portion of their diet, many studies have been conducted on how to reduce phytic acid. Many of these studies aren’t helpful for us as home cooks, as they are researching how to grow low phytic acid grain, or using methods not available to us at home to reduce phytic acid. But there are still many available that help home cooks have a little more knowledge in how to prepare their grains.
The amount of phytic acid in a certain grain or legume depends on a lot of factors. One study found that the phytic acid content of lentils was affected (among numerous other factors) by the growing temperature! Cooler temperatures during the growing season produced lentils with a lower phytic acid content. [vi] Another study concluded that there was “significant” differences in phytic acid content in different beans and chickpeas.[vii] Phytic acid will also be higher in foods grown using high-phosphate fertilizers in comparison to those grown in natural compost. [viii]Different varieties of the same grain may also have different levels of phytic acid. What this means is that the phytic acid content in grains and legumes are not clear cut and consistent but highly variable.
Phytase is the enzyme generally present in phytic containing grains and legumes that neutralizes phytic acid. Sprouting, soaking and fermenting raw grains allows phytase to become activated, which then reduces the phytic acid. We as humans do produce some phytase in our bodies, which explains why some can eat a high, unsoaked whole grain diet without negative impact. Since lactobacilli and other digestive microflora can also produce phytase, [ix]those of us with a robust intestinal health will have a much easier time digesting grains, soaked or unsoaked. But regardless, all of us can benefit from less phytic acid in our grains.
How much difference does it make to remove phytic acid?
While it is well established that phytic acid does indeed bind with minerals, I wondered if there were studies that actually showed the difference it made in reducing or eliminating phytic acid. Here is a sampling of some studies I found.
As I mentioned, iron absorption is a major problem for many countries. One study used phytase to fully degrade the phytic acid from many different grains. This was then given to human adults and they found that the “dephytinization” (the removal of phytic acid) of the grains dramatically increased iron absorption except for a high tannin sorghum porridge. This was true only if the cereal was made without milk (milk interferes with the absorption of iron, so when it was made with milk the dephytinization did not help iron levels). [x]
Another study found that the dephytinization of an oat based beverage with the addition of citric acid and iron supplmentation “significantly” increased iron absorption. [xi] I’ve also found several studies demonstrating that removing phytic acid from cereals made for weaning babies had a “beneficial” affect on iron and zinc bioavailability when reconstituted with water. [xii]There are also many animal studies showing better growth and health when feed phytic free feed. Rats and chickens (and other animals) both grow better and are healthier when either supplemented with phytase or given dephytinized feed. Because we do feed grains to our animals unless they are completely pastured, many studies test whether reducing the phytic acid in their feed would help them grow better/faster, stronger/healthier and more productive. Many farmers give phytase to their animals so they they have better nutrition. If they have better health and growth with a limited phytic acid diet, we probably will too.
I would say that there is enough research done at this point to demonstrate that removing phytic acid does help you absorb more minerals (which in turn provides a “healthier diet for you”) as well as helping you better digest grains and legumes(more info on that to come).
But does phytic acid have any benefits?
I thought that Ramiel Nagel did an excellent job summarizing some of the latest research on phytic acid having positive effects. Here it is.
“As evidence of the detrimental effects of phytates accumulates, reports on alleged beneficial effects have also emerged. In fact, a whole book, Food Phytates, published in 2001 by CRC press, attempts to build a case for “phytates’ potential ability to lower blood glucose, reduce cholesterol and triacylglycerols, and reduce the risks of cancer and heart disease.”14
One argument for the beneficial effects of phytates is based on the premise that they act as anti-oxidants in the body. But recent studies indicate that an overabundance of anti-oxidants is not necessarily a good thing as these compounds will inhibit the vital process of oxidation, not only in our cells but also in the process of digestion.
Another theory holds that phytates bind to extra iron or toxic minerals and remove them from the body, thus acting as chelators and promoting detoxification. As with all anti-nutrients, phytates may play a therapeutic role in certain cases.
For example, researchers claim that phytic acid may help prevent colon cancer and other cancers.15 Phytic acid is one of few chelating therapies used for uranium removal.16
Phytic acid’s chelating effect may serve to prevent, inhibit, or even cure some cancers by depriving those cells of the minerals (especially iron) they need to reproduce.17 The deprivation of essential minerals like iron would, much like other broad treatments for cancer, also have negative effects on non-cancerous cells. For example, prolonged use of phytic acid to clear excess iron may deprive other cells in the body that require iron (such as red blood cells).
One theory is that phytates can help patients with kidney stones by removing excess minerals from the body. However, a long-term study involving over forty-five thousand men found no correlation between kidney stone risk and dietary intake of phytic acid.18
Phytates also have the potential for use in soil remediation, to immobilize uranium, nickel and other inorganic contaminants.19 “ Read the full article here.
The hundred dollar question is how to effectively reduce or remove phytic acid from our grains and legumes. Stay tuned for more research on that topic!
[i] Wise Traditions, Living with Phytic Acid by Ramiel Nagel and Fermented Cereals a Global Persespective ( http://www.fao.org/docrep/x2184e/x2184e05.htm#ant)
[ii] Same as above
[iii] Dietary roles of phytate and pytase in hum nutrition: a review, in Food Chemistry, 2010 June 15, v120, no.4, pages 945-959. 120 4 and Phytate: Impact on Environemnt and Human Nutrition. A Challenge of molecular bredding in Journal of Zhejiang University. Science. March; Vol. 9, pp165-91
[iv] Living with Phytic Acid, Preparing GRains, Nuts, Seeds and Beans for Maximum Nutrition, by Ramiel Nagel, Published in Wise Traditions, Vol 11 Number 1 Spring 2010
[v] Botany: Final Piece in Phytate Jigsaw Discovered, ScienceDaily (Apr. 27, 2010)
[vi] Phytic acid and Fe and Zn concentration in lentil seeds is influences by temperature during seed filling period. Food Chemistry, Sep2010, Vol. 122 Issue 1, p. 254-259
[vii] Effect of cooking on the composition of beans and chickpeas, Food research International, March 2010, Vol. 43, Issue 2, p589-594
[viii] Srivastava Bn and other. Influence of Fertilizers and Manures on the Content of Phytein and other Froms of Phosphorus in Wheat and their relation to soil phosphorus. Journal of Indian Society of Soil Science. 1955, p. 33-40
[ix] Famularo G and others. Probiotic lactobacilli: an innovative tool to correct the malabsorption syndrome of vegetarians? Medical Hypotheses 2005 65(6):1132-5
[x] Degradation of phytic acid in cereal porridges improves iron absorption by human subjects, American Journal of Clinical Nutrition, Vol. 77, No. 5, 1213-1219, May 2003 (http://www.ajcn.org/cgi/content/full/77/5/1213)
[xi] Improved iron bioavailability in an oat-based beverage: the combined effect of citric acid addition, dephytinization and iron supplementation. European Journal of Nutrition: Ma2007, Vol. 46 Issue 2, p95-102
[xii] Effect on dephytinization on bioavailablity of iron, calcium and zinc from infant cereals assessed in the Caco-2 cell model, Department of food science and Nutrition, Faculty of Veterinary Science and Food Science and Technology, Murcia University, Murcia, Spain.