Grains Part II – Phytates


Part II: Are Grains Healthy for You?

Caveman Doctor recently received several questions regarding grains and if they were healthy. One person even referred to quinoa as a “superfood.” Caveman doctor was really confused as to what a grain was since he never ate them during his time on Earth. He was also really confused by the term superfood and remembered that the last time he ate a superfood, he got supersick and was in his cave bathroom for an entire day. After he asked around, he got his hands on some oats and wheat and figured he would give them a try. At first, he didn’t believe they were food as they were lacking the bold color, smell, and feel of foods he was used to eating. He tasted the oats and wheat, but immediately spit them out due to their bland taste. Caveman Doctor is used to colorful, flavorful foods and was very confused as to why anyone would eat these things known as grains.
In the next three parts of the Grains Series, I will review several health issues with grains before the final post.

Chemicals Found in Grains That Question Their Health Benefits:


1. Phytic Acid

Number one on the list is phytic acid.  This substance is the storage form of phosphorus in many plants, especially legumes, nuts, seeds, and grains. It is also found in green leafy vegetables, but grains contain considerably higher levels. It does have some antioxidant effects like many fruits and vegetables, however, it has many negatives that fruits and vegetables do not.  Firstly, it is indigestible when consumed by humans. It chelates certain nutrients (binds to them and prohibits their absorption into our bodies), including calcium, magnesium, zinc, vitamin B3 (niacin), and iron. Deficiency of niacin is called pellagra, a disease that is severely debilitating and has plagued corn-based societies for centuries. Interestingly, the USDA website discussed at length how grains are great sources of iron, niacin, and magnesium, but never mentions that the chemicals in the grains impede your body’s ability to absorb these minerals.
Do you have low calcium or magnesium?  Are you at risk for osteoporosis?  Is your doctor telling you to take a calcium pill?  Maybe you should consider the phytic acids from grains in your diet and other food sources as they may be inhibiting your ability to absorb calcium.  We often hear that most of us don’t have enough calcium in our diet.  Maybe the real problem is that the grains we are eating are stopping our body from absorbing calcium. There are many people that questions input factors causing osteoporosis and instead looks at output factors, i.e. it’s not that people with low calcium levels don’t get enough, they just don’t absorb enough or lose too much in the GI tract1.
Finally, phytates inhibit and may even shut off several enzymes that help us digest proteins, carbohydrates, and even fats, further impairing the absorption of nutrients.2 Protein supplements, from bodybuilders to patients with cancer-induced weight loss (cachexia), are a billion dollar industry in the United States as people are often trying to maximize their intake of high quality proteins. Yet, grains contain a chemical that decreases our body’s ability to digest protein (not to mention carbohydrates and fat as well). Have you ever eaten a huge amount of carbohydrates, and afterwards experienced GI upset and bloating? This is likely because of undigested sugar in your large bowel that was eventually digested. However your body did not do the hard work of digestion, the bacteria that live in your GI tract did the job instead. To say thanks for the free meal, these bacteria tend to give off noxious gases and cause GI discomfort and bloating. This is what happens to the sugar lactose (found in milk and dairy) when consumed by lactose intolerant individuals – they don’t have the enzyme to break down lactose, leaving it as a feast for the GI bacteria.  What do you think happens to all the foods in your gut when you can’t digest them?
To add insult to injury, these indigestible phytates, when passing through your GI tract unabsorbed and binding other elements, cause severe environmental damage when they leave your body upon entering the soil and water supply. Consequently, when grains are fed to animals, this happens to a much larger degree. When vegetarian groups quote the environmental effects of raising animals, they should also consider what the animals are eating. Several nutritionists suggest methods of offsetting the harmful effects of phytates, such as consuming them in the presence of vitamin C. Call me crazy, but I like to consider another method: minimizing or avoiding the substance that causes the damage in the first place.
Some people even regard the binding properties of phytates as potentially beneficial, for instance, in cases of iron toxicity as this causes some problems after long periods of accumulation. Consuming phytates is a way of leaching out this iron. Remember, cavemen often experienced daily trauma and also got attacked by sabertooth tigers, both resulting in bleeding. This is the easiest method of lowering your iron (and some cavemen lifestyle followers even give blood periodically to mimic this). However, iron is continuously lost in your sweat, GI tract, and during menstruation and rates of iron overload in the general population is limited mostly to those with genetic diseases that cause high levels.3 Our intestines have a remarkable ability to store and release iron to help keep our levels normal.4 Better yet, iron loss increases markedly in your sweat during exercise, giving you a much healthier means of dropping some iron (while you pump some iron…) and increasing our health in dozens of other ways.5 Overall, touting the health benefits of a substance as interfering with the digestion of nutrients is a tough sells and smells fishy (or grainy in this sense) of involvement by the grain industry. Furthermore, most people are iron deficient and so phytates would only exacerbate the problem.
It seems as though the verdict is still out on the overall viewpoint of phytates, though the harmful aspects to both the human body and the environment are well established and likely overwhelm any benefits.

In Conclusion:

  1. Phytates are found in high amounts in grains.
  2. They have many documented negative influences on health, including losses of many important nutrients, including calcium, magnesium, zinc, vitamin B3, and iron.
  3. They potentially decrease the function of our digestive enzymes, resulting in undigested protein, fat, and carbohydrates.
  4. They possibly have some positive influences on health such as antioxidant activity and iron loss, though the iron-decreasing theories are likely overrated and applicable only to very few people with genetic diseases that cause iron overload.
  5. The positive influences can likely be achieved through other foods without the cost of the negatives.
  6. They have documented harmful effects on soil and the environment.



1. Basha B, Rao DS, Han Z-H, Parfitt AM. Osteomalacia due to vitamin D depletion: a neglected consequence of intestinal malabsorption. The American journal of medicine 2000;108(4): 296-300.

2. Singh M, Krikorian AD. Inhibition of trypsin activity in vitro by phytate. Journal of agricultural and food chemistry 1982;30(4): 799-800.

3. Andrews NC. Disorders of Iron Metabolism. New England Journal of Medicine 1999;341(26): 1986-95.

4. Conrad ME, Weintraub LR, Crosby WH. The Role of the Intestine in Iron Kinetics. The Journal of clinical investigation 1964;43: 963-74.

5. Waller MF, Haymes EM. The effects of heat and exercise on sweat iron loss. Medicine and science in sports and exercise 1996;28(2): 197-203.
© 2015 CDR Health and Nutrition, LLC. All Rights Reserved.


  1. sweetopiagirl

    Reblogged this on Inspiredweightloss.

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  7. kh

    I have read alot about phytic acid and other articles usually include seeds, grains, beans and nuts. although in one of your other posts you said you sometimes cheat with nuts. Im asking because my body really agrees with the caveman diet but I dont eat meat so I need protein from other sources. Just wondering about the caveman’s opinion on this one

    1. cavemandoctor (Post author)

      Hi, nuts are fine. I personally roast them and some people soak them to offset the phytates, etc.

  8. kh

    Also I’m allergic to seafood so I am unable to take Omega 3 or Cod liver oil. Are there alternatives?

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