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All About Whole Grains, the Difference Between Phytates & Phytic Acid, & What Is the Role of Phytase in Soaking Grains?

What is a whole grain, anyway? What are phytates and phytic acid? Why should you soak whole grains? Read on to learn. 

The Food Pyramid says eat more whole grains, and big food companies comply with “Made With Whole Grain!” cereals and bread, and coordinating advertisements.

Michael Pollan says don’t eat foods that have advertisements.

For more than one reason, he may be right when it comes to whole grains.

If you eat whole grain cereal, bread, pasta, or rice, keep reading to see what nutrients you may be missing.

whole grains, cereal, pasta

What Is a Whole Grain?

Why keep grains whole? The whole grain has all the nutrients God put into grains: fiber, protein, healthy fats, and lots of vitamins and minerals. The straight starch in white flour, in the absence of the whole, is quickly turned into simple sugars in your body. This has two effects:

  • Spikes your blood sugar
  • Is easily turned into fat for storage

In my personal opinion, if God created a food with certain parts, those parts should be eaten together, unless there is a clear reason to do otherwise. In the case of whole grains, however, it may become a question not of “separated or united” but of “how to prepare”.

RELATED: Storing flour long-term

What is a whole grain? Diagram of a wheat kernel showing endosperm, germ, and bran

So what is a whole grain? A kernel of grain has three parts: endosperm, germ, and bran. This applies to all grains, like rice, oats, wheat, barley and more.

The endosperm contains:

  • Carbohydrates
  • Protein
  • A few vitamins

The germ contains:

  • B vitamins
  • Vitamin E
  • Antioxidants
  • Mostly polyunsaturated fats
  • Lots of folic acid (important for pregnancy)
  • Iron, zinc and other minerals

The bran contains:

  • Main source of the grain’s fiber
  • Most phytonutrients and minerals
  • Antioxidants
  • Phytates

All these parts can be separated. You can buy wheat bran. You can buy wheat germ. (Health food folks like to do this.) You can buy wheat endosperm. It’s called “white flour”. (Processed food companies like to do this.)

Because of its oils, the wheat germ is likely to go rancid quickly. In order to extend the shelf life, food manufacturers strip off the germ and the bran so that the remaining endosperm, although lacking in nutrition, can sit around for a long time and wait for people to consume it. If only it was worth consuming!

The Possible Dangers of Eating Whole Grains

I can hear you now. “What? There are dangers associated with eating whole grains?”

Possibly. The phytates in the bran and the fats in the germ can cause some unique problems for those of us trying to follow recommendations and increase our whole grain consumption.

  1. Phytates are largely an anti-nutrient, which means they do more to take nutrients from our bodies than share them. When we eat grains with the bran intact, the phytates bind to minerals like calcium, iron, magnesium and phosphorus so that our systems can’t make use of them. We’re paying a premium for whole grain products that aren’t delivering on their nutritional profile in reality.
  2. Rancid oils are damaging to our health, and certain processes cause the oils in the whole grain germ to become oxidized and/or rancid, even if we can’t taste it.

This is why I challenged you to raise your consciousness of grains by trying to avoid them at one meal or snack. They’re not the easy health food, even in whole form, that they’re made out to be when the government recommends 6-11 servings a day.

whole grain breads

Whole Grain Cereals for Breakfast

Should we avoid whole grain cereals? Yes.

First, if regular whole grains really are bound up by phytates, you might as well save your money on the whole grain upgrade, because you’re not getting anything helpful from the whole grains anyway.

Second, almost all breakfast whole grain cereals are made by a process called extrusion. My uncle was actually one of the people on the ground floor of designing and implementing the process, and he explained it to me around the campfire last summer. Here’s my best shot at remembering (why didn’t I write it down right away?):

  • Whole puffed grains (think rice cereal, corn pops, etc) are prepared for processing, then placed inside a huge vat, where the pressure is increased to a certain point.
  • When the pressure is released, the grains literally explode upward – POP! – and puff out to the shape you see in your cereal bowl. Think popcorn, industrial-style. The calculated pressure gives a more uniform shape to the grains.
  • Cereal shapes, like Os, stars, and even flakes, are made by a similar process. Even shredded wheat (and Triscuit crackers) is extruded to make the “shreds” that shape.
  • The ingredients are mixed together to make a cereal “dough”.
  • This “dough” passes down a chamber, much like that of a gun, and as it is heated to “bake” it, it is also extruded through a mold to make the shape. This again is more like a gun firing than anything else, complete with the pow factor and the extreme pressure on the grains.
  • When using whole grains, the delicate fats and Vitamin E in the germ are damaged.

The exceptions to this process include some granola type cereals, some Kashi cereals, and Grape Nuts. Grape Nuts, if you’re a science junkie like me and curious, are actually made by baking a 10-lb loaf of dense “bread” at a very low temperature until it is completely solid for a few inches all the way around. That part is smashed up to make the cereal! If you can’t stay away from packaged cereals, Grape Nuts would seem a better choice amongst the poor options.

Here is an article at the Weston A. Price Foundation that cites two unpublished research studies that demonstrate the dangers of extruded grain breakfast cereals. I’m not sure that I buy it all, but it’s an interesting read nonetheless.

whole grain cereals

The Bottom Line on Whole Grains

  • White flour and refined grains have almost no nutritional value, but they will fill you up, and they’re cheap.
  • Whole grains have potential for nutritional value, but they may have some drawbacks, and they’re expensive in comparison.
  • However, whole grains must trump processed grains if only because they are metabolized more slowly and give at least a bit of protein and fat to help your body deal with the starches.
  • Research shows that soured whole grains (this sourdough) have a great deal more available nutrients. I’ll show you how to make your own sourdough in three weeks!
  • Research may show that the process of soaking grains can also improve their nutrient profile.

We’ve explored the research on soaking grains in-depth here at KS, and there is so much more research and so many journal articles to read on this topic, but in the next section I’ll focus on defining phytates, phytic acid, and phytase, and explain their roles in the whole grain.

What Are Phytates and Phytic Acid?

phytic acid in whole grains

If you’re familiar at all with the concept of soaking grains put forth by Nourishing Traditions, you’ll know that the prime evildoer in the battle is called phytates, often used synonymously with phytic acid.

Phytates and phytic acid are not the same thing. They are related and work together, but one cannot speak of them interchangeably.

Within the bran layer of a grain/seed, we find phosphorus bound up and unavailable, along with calcium, magnesium, iron and zinc.

Phytic acid is billed as both an antioxidant and an anti-nutrient, clouding the issue from the get-go. It’s technically called a hexaphosphoinositol and is a powerful chelator, which means it binds with other minerals and takes them out of your system. This could be positive, toxin-reducing, and cancer-fighting, or negative, prohibiting your system from absorbing minerals.

That is, if phytic acid can get free in the first place.

Phytates are the bond holding phytic acid. They are officially the “salt of the phytic acid,” which can be broken in a number of ways.

  1. in the gut with stomach acid
  2. via germination
  3. under the enzyme phytase

Unfortunately, this is all assuming one would want to break down their phytates. Doing so releases free phytic acid into the system, which is looking for something to fulfill it. That something could be your iron reserve.

During germination, the phytate is “hydrolyzed”, which is a fancy way of saying broken into compounds by reacting with water. This is much like when salt is dissolved into water. Phosphorus, magnesium, iron and calcium are made available for the development of seedlings (and you, too!). Like salt, however, which can return to it solid state if the water is evaporated, phytates can potentially bond back to the minerals because its electron needs are not fulfilled.

Stomach acid is a pH of 1, whereas the vinegar, lemon juice, etc. recommended by Sally Fallon and crew ranges from 3.5-4.5, about 1000-10,000 times weaker than the digestive juices. If an acid at that pH could affect the phytate bond, the grain would have to be cracked for it to happen, as the bran itself is too tough to digest and too tough for mild acids.

Germination only begins when the seed is intact or cracked, not ground. It’s possible that more nutrients are made available through germination, and that’s what soaking purports to do: begin the growing process of a seed.

Two procedural questions quickly arise from the two paragraphs above:

  1. If the grain has to be cracked for acidulated liquid to potentially affect it, what does soaking whole rice, barley, or dry beans do?
  2. If germination is the key, how can one soak flour, which is way beyond the ability to germinate?

Part of the answers lies in understanding the goal of the acid in the water. The enzyme phytase is the key to understanding a lot of what happens when grains are soaked in an acidic medium. Keep reading to learn about how phytase works.

Questions one and two are sort of diametrically opposed, yet answer each other. The goal in soaking whole seeds is often to begin germination, which doesn’t need an acid medium, and the goal of soaking flour is to activate the phytase, not germinate the seed. There are still more details to be nailed down, but I’m not ruling out that soaking does something and has a genuinely possible goal.

Other questions that need to be addressed:

  1. Is phytic acid good or bad?
  2. Do we want to release phytic acid in the first place?
  3. If phytic acid is released into the soak water, does it need to be rinsed off before cooking so that the phytic acid doesn’t bond back up with the minerals you’re trying to release?

whole grains in field

What Is Phytase?

Phytase is an enzyme. An enzyme is a protein in a living thing that causes action. Scientists call them catalysts; I’d just call them doers. They make life happen. Enzymes are not always in an active state, but can be dormant and need certain conditions to be activated.

Imagine a vehicle sitting in your driveway. Unless you have the key, it’s just a large object blocking your path. Once you have the key, however, it becomes a mode of transportation and quite useful. Phytase is the key to starting the engine within the grain. Making the phytates move out of the way is not possible without the “key” of phytase. (Am I the Charlie Epps of nutrition? Maybe I’ll have a TV show someday.)

How does phytase work?

The action we want phytase to complete, if you remember our discussion of phytates and phytic acid, is to separate the phytates and phytic acid from one another, thus releasing phosphorus and other minerals trapped in that bond. When activated, phytase attaches to the phytate to help release the phosphorus (phytic acid).

Because it’s an enzyme, phytase must be alive in order to have the opportunity to be activated. Heat would damage or destroy the enzyme, so do realize that we’re only talking about raw foods here. Anything that has been cooked, baked, steamed (rolled oats???) will not have active enzymes.

Where is phytase found?

Phytase is in plants, including grains, as well as in the form of microbial phytase in yeast and sourdough leaven.

Various plants have different amounts of the enzyme phytase. For example, wheat, rye, and barley have considerable amounts of phytase, whereas corn, oats, sorghum, and millet have little or no phytase activity. Baker’s yeast also contains phytase.

There is even some evidence of phytase in the digestive system, so some researchers think phytates are broken down to a certain extent by normal digestion. However, very few studies have been done on human digestion seeking phytase specifically.

Here is a key quote from one of them:

“Studies in humans showed that 37–66% of dietary phytate is degraded during digestion in the stomach and small intestine when the diet is rich in plant food phytases.”(3)

Note: remember that only raw plants, grains, etc count. The American diet includes much cooked food, therefore as a whole we are very low in phytases.

How is phytase activated?

There’s the rub. I have more to learn on this subject, but it’s key to understanding our issue of soaking grains. If phytates are going to be broken away from phytic acid, at least in non-intact grains that can no longer germinate (think flour), you’re going to need phytase. How to get it to leave its dormant state and work on the tough bonds is up for discussion to a certain extent, and I will come back to this topic again later.

One fact I know so far: phytase is activated through germination. That’s why we’re sprouting things this week here at KS. I like to focus on where the research findings are clear and well-documented, similar to last week’s challenge to start some sourdough because that is the most effective way to reduce the phytates in bread.

For cracked grains and milled flour, there are various perspectives on possibility, pH, temperature, and method for activating phytase. More to come!

Phytase in freshly ground grain

Enzymes degrade over time, and once the hull of a grain is broken, they’re more open to the processes that will break them down. Once a whole grain is milled into flour, the phytase content immediately begins to decrease. Therefore, to have the best chance of dissolving phytates and releasing minerals, one would want the highest phytase levels possible. Freshly ground flour is the optimal choice.

Some have asked if soaking or souring freshly ground flour defeats the purpose: if it’s sitting around soaking for so long, won’t the nutrients begin to fade anyway? Although I don’t have strong evidence for this, my common sense tells me that when you use freshly ground flour, the high levels of phytase are then activated by the souring (or perhaps, soaking). Once activated, they aren’t going to degrade. They’re already doing their job. That’s my hunch!

The healthiest bread is sourdough – learn how to make a sourdough starter and bake bread.

What will you do about whole grains?

Disclaimer: As much as I’d like to pretend I’m a real researcher in uncharted territory, let’s keep it real: I’m just a mom with a computer and a yen for knowledge.


  • Applegate, T. J., & Angel, R. (2004). Phytase: Basics of Enzyme Function. Retrieved from
  • Campbell, J., Hauser, M., & Hill, S. (1991). NUTRITIONAL CHARACTERISTICS of ORGANIC, FRESHLY STONE-GROUND, SOURDOUGH & – CONVENTIONAL BREADS. Retrieved August 05, 2020, from
  • Schlemmer, U., Frølich, W., Prieto, R. M., & Grases, F. (2009). Phytate in foods and significance for humans: Food sources, intake, processing, bioavailability, protective role and analysis. Molecular Nutrition & Food Research, 53(S2). doi:10.1002/mnfr.200900099
  • Nielsen, M. M., Damstrup, M. L., Thomsen, A. D., Rasmussen, S. K., & Hansen, Å. (2006). Phytase activity and degradation of phytic acid during rye bread making. European Food Research and Technology, 225(2), 173-181. doi:10.1007/s00217-006-0397-7
  • i>Hallberg, L., Rossander, L., & Skånberg, A. B. (1987). Phytates and the inhibitory effect of bran on iron absorption in man. The American Journal of Clinical Nutrition, 45(5), 988-996. doi:10.1093/ajcn/45.5.988
  • Personal Emails with Dr. Teri O’Brien, PhD biologist who researches plants.
Unless otherwise credited, photos are owned by the author or used with a license from Canva or Deposit Photos.

29 thoughts on “All About Whole Grains, the Difference Between Phytates & Phytic Acid, & What Is the Role of Phytase in Soaking Grains?”

  1. Amazed that nobody seems to have asked the obvious question, i.e….

    Since Phytase is added to any number of commercial animal feeds, can we get a good supplemental source of it to add to our food? Or maybe something to just quickly neck a capsule of phytase before eating grainy foods?

    Anyone have any experience of this?

    1. Carolyn @ Kitchen Stewardship

      Phytase is in many digestive enzymes. I don’t know enough about it to know if that is insufficient so that’s why soaking is still recommended, or it’s just a cheaper option if you don’t want to buy a supplement. With soaking your grains you don’t have to check if the supplement company is reputable or worry about fillers or other ingredients. But short answer yes, there are supplements containing phytase that you can look into. I hope that helps a bit!

  2. Roger Windsor

    OK, so phytins bind some minerals, and those minerals are not available for human nutrition. But, is that a problem?

    Do we know that the missing minerals made unavailable by phytins are actually needed for good health? Yes, we need minerals. But is there any evidence to show that in a whole foods diet we are NOT getting enough minerals when we consume unsoaked grains?

    Look at it this way . . .
    Some water soluble vitamins are destroyed by cooking. Should we then conclude all food should be eaten raw? Do we actually suffer by not getting those vitamins destroyed by cooking? Or does a natural foods diet contain enough vitamins even if we consume a lot of cooked foods?

    Have you ever looked closely at a soaked grain? Try soaking a few grains of brown rice overnight. Before soaking, they are hard, and you cannot break them in half with your nail. But after soaking the grains swell up, turn more white colored, and are easily broken with your nail.

    Why is this significant?
    Because when traditional people soaked their grains, they may not have been doing it to improve nutrition, but rather to reduce cooking time and also reduce the amount of firewood needed for cooking. In addition, soaked grains seemed to me to be more tender and taste better, but I have not tested this in any objective way.

    Dr. Weston Price found that isolated groups of people eating a natural diet and lots of grains were very healthy, with little tooth decay or degenerative diseases. This suggests that a high-grain diet is beneficial. However, I would like to know whether these people soaked their grains or not. But even if they did, the only benefit may have been that it saved them cooking time and firewood.

    While I don’t know if it’s nutritionally necessary to neutralize phytins, I still soak all my grains . . . and will continue to do so. Saving energy (cooking gas or electricity) and improved taste — what’s not to like?
    Whole grain brown rice is a major part of my diet, and I soak it overnight before cooking. Regards wheat, I make sourdough bread, which is a form of soaking since the dough takes many hours to rise. When I use commercial yeast, I make the dough the night before, adding the yeast and baking in the morning.

    1. Katie Kimball @ Kitchen Stewardship

      Roger, I love this evaluative thinking — really interesting! I do actually try to preserve as many nutrients as I can when I cook veggies too, for example steaming vs. boiling. So it’s not about getting every last mineral out…but getting the most we can. I agree with you though, I’ll soak for improved taste too! 🙂 Katie

  3. Hi. Great article. Is it true that freezing kills phytase? I saw that in an article about phytic acid and now I’m scared to store my oats in the freezer. Can you shed some light on this?

    1. Katie Kimball @ Kitchen Stewardship

      Storing whole grains in the freezer is a good idea – I wouldn’t worry about phytase. There’s hardly any in oats anyway.

  4. When soaking oats, is it okay to leave out the acid medium? And when adding the whole grain wheat flour, does it have to be freshly ground? I do not own a grinder and am unable to at all, so I was thinking of just buying Bob’s Red Mill spelt flour to soak. Can soaking their oat flour be good too?

    1. Katie Kimball @ Kitchen Stewardship

      There’s actually a lot of changing going on in the world of “soaking grains” – Amanda Rose of Rebuild from Depression says to skip the acid everyt ime ( She does recommend freshly ground, but who knows? Hopefully there’s phytase in store whole wheat, too. Any oats will have phytic acid, even oat flour, so yes, a soak would be a good thing.
      🙂 Katie

      1. Katie,
        I thought I would add to your post. Oats have more phytic acid than many other grains. So they do need a good soak or long fermentation. Whether the phytase is food in store bought flour depends on the grinding process. Heat destroys phytase. The other down side of store bought grain flours is that the nutitive value deteriorates over time. How much depends on storage methods and time before it is used. This is also true of fresh vegetables. They begin losing nutritional value from the time they are harvested, and continue to lose nutrients during shipping and display in stores. Frozen veggies actually have more nutrition than the ones that can be bought in the store as “fresh”.

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  6. I am just beginning to learn about all this phytic acid stuff and I find this all very interesting. I see people referring to ‘short fermentation’ and ‘long fermentation’ and I am confused by what they mean. Please explain.

    1. Sandra,
      Short fermentation is used in recipes that use more yeast such as 2 tsp or more and the first rise is usually 1 to 2 hours or less. For long fermentation, generally much less yeast is used (1/4 to 1/2 tsp) and the first rise can be from 12 to 18 hours. Long fermentation can be done either in the refrigerator or on the counter, and has a similar purpose as soaking grain or flour. During a long fermentation, the phytase has time to activate and break down the phytic acid to release nutrients in the grain. Any bread recipe can be converted to long fermentation by reducing the amount of yeast and also allowing dough to rise for at least 12 hours. This not only releases nutrients but develops more flavor in the bread.

      1. Katie Kimball @ Kitchen Stewardship

        Thanks, Judy! Your explanation was far better than I would have offered! 🙂 Katie

        1. Thanks Katie,
          Healthy foods such as proper use of whole grains, non-GMO foods, and meat from natural fed animals has become a passion for me. I truly believe that most of the health issues of our children and even our aged (alzheimer’s, diabetes, athritis, etc.) are all a result of what we are eating. Everyone can benefit from learning more about healthier diets.

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  8. I thought I might also mention that people adding whole grain flours to short fermentation recipes could actually be doing themselves harm rather than receiving the benefits of whole grains.

    1. Crazy, right, in light of current US Government recommendations for more whole grains?! Thanks for adding your thoughts and research to the post! 🙂 katie

  9. Hi Katie,
    I have been doing a of research on phytic acid and the enzyme phytase. I have been baking all of our breads for a few years, and always do a long fermentation because when I started, I learned that a long fermentation released nutrients in whole grains, but I didn’t know why. In recipes that I use for long fermentation, I greatly reduce the amount of yeast that I use using more yeast greatly increased the carbon dioxide and alcohols produced by the yeast which will kill the yeast during a long fermentation.

    More recently, I learned about phytase and phytic acid. The whole thing now makes perfect sense to me because I am also into plants and botany. All seeds, including grains (rice included) contains phytic acid to keep seeds dormant so that they don’t start to germinate in unfavorable condition. When growing conditions become warm and moist, the pytase is activated to release nutrients to the embryo of the seed so that it starts to germinate.

    By soaking grains or by using long fermentation processes in bread making, pytase is activated to release nutrients. One distubing thing that I found out is that the phytic acid in grains, if not broken down by pytase, will actually absorb the nutrients in meals that is eaten with. This is one of the reasons that people in countries having a large part of their diets consisting of grain, such as rice in China, there are more dietary deficiencies that cause such diseases as rickets.

  10. Just wondered if you had seen this article and what you think of it???

    1. Yes, and my thoughts are woven into this series:
      🙂 Katie

  11. Rachel Wisdom

    Sorry – I posted this comment in another place when I meant to post here:

    Thank you so much for all of your research Katie! I’ve been trying to learn more about these things for quite a while as my husband has Crohn’s disease and I’d like to figure out what we can do to help him from a dietary standpoint. It’s difficult though because so much of what I read is conflicting and/or just sounds like hype or bunk.

    One specific thing I am wondering. Have you seen anything in your research about taking a phytase supplement? My dh’s digestive enzyme supplement has some, and I am wondering if all the angst surrounding this stuff (to soak or not to soak, does it actually do anything anyway if there’s little to no phytase left in my flour, etc. ) is pointless.

    That’s the long way of saying, what about a phytase supplement?

    I’m adding you to my Google Reader.

    1. Check out the Specific Carbohydrate Diet (SCD).
      It heals diseases like Krohn’s, Colitis, and a whole lot of other conditions. is a direct link to a helpful website.
      I’ve got my son on this diet to heal the effects of celiac disease, which has made his gut quite sick.
      It’s worth your investment of time and energy if you really want to heal your loved one.

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  13. jenna Food WIth Kid Appeal

    i think alton brown should have you on a soaking/sprouting episode of good eats!
    .-= jenna Food WIth Kid Appeal´s last blog ..Green Food St. Patrick’s Day Recipe Roundup – Green Macaroni & Cheese =-.

    1. Jenna,
      Is it bad that I had to Google Alton Brown to see what that meant? I thought he might be some other, bigger blogger. Food Network? Ya think? I get giddy just thinking about stuff like that; it’s bad for my pride. But now you got me thinking… That would be such fun!
      Thanks! Katie

  14. Simple in France

    Thanks for doing all that footwork! I’ve been interested for some time in sprouting, sourdough, soaking etc, but I’m one of those people that really likes to know WHY people say something is healthy. Otherwise, it all just sounds like another fad to me. Thanks for breaking it into small bites too.
    .-= Simple in France´s last blog ..Nearing nine months in France . . . =-.

  15. Great information — thank you. I have been adding a spoonful of whole wheat flour to my steel-cut oats when I soak them to get the extra phytase that the oats lack. Now I’m wondering if most of the phytase is already degraded in the ground whole wheat flour…
    Also, it’s really good to know that raw vegetable phytases help us during digestion.
    .-= Ellen´s last blog ..Cooking with Sprouted Wheat: Pumpkin Raisin Muffins =-.

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