Are Phytates In Food Dangerous?
As I’ve started studying my nutritional habits more closely over the last several months, one of the subjects
I’ve questioned is the strong bias against grains expressed by followers of the primal lifestyle. Specifically, phytates. Not that I think the concern is misplaced, but I would just like to better understand the sentiment. A recent post at Zen to Fitness on the problem with grains made me take notice, because it deals specifically with that question. One of the things mentioned was the presence of phytates in food.
What Are Phytates?
Phytates are the salts of phytic acid. More correctly named inositol hexakisphosphate, the acid (or salt) is a phosphorus based compound found in the many plants. Specifically those high in fiber, with concentrations generally being highest in foods containing large amounts of insoluble fiber. Occurring most frequently in nuts, seeds, legumes, and whole grains, phytates serve as the primary mechanism by which plants store phosphorus. Like so many other things in life, there is some debate about the health effects of phytates. Detractors claim they exhibit an anti-nutrient effect, while promoters tout their potential for reducing a variety of ills.
Some sources of phytates include:
| Food | % Min (Dry) | % Max (Dry) |
|---|---|---|
| Brazilian Nuts | 1.97 | 6.34 |
| Almonds | 1.35 | 3.22 |
| Tofu | 1.46 | 2.90 |
| Oatmeal | 0.89 | 2.40 |
| Pinto Beans | 2.38 | 2.38 |
| Soy Protein | 1.24 | 2.17 |
| Corn | 0.75 | 2.22 |
| Whole Wheat Bread | 0.43 | 1.05 |
| Brown Rice | 0.84 | 0.99 |
| Polished Rice | 0.14 | 0.60 |
Phytates As Anti-Nutrients
For quite some time, phytates have been viewed as “anti-nutrients.” Since non-ruminant animals (i.e. humans) lack the proper enzymes to digest phytates, the phosphorus in these molecules is generally not available (for nutritional purposes) to humans. This means that consuming foods high in phytates will not serve to meet daily requirements for phosphorus.
From a nutritional perspective, phytic acid is known to strongly complex many cations, and when in the presence of these nutrients, the acid reacts to form a salt, known as a phytate. Included in that list are minerals that will complex with phytic acid are: calcium, magnesium, zinc, and iron. This means that phytic acid will scavenge these minerals, reducing their availability to serve nutritional needs, which concerns some nutritional experts, as it presents the potential for nutritional deficiencies. From a practical perspective, this has the greatest potential to impact vegetarians, pregnant women, and the extremely malnourished, due their generally low mineral consumption.
Nutritional Benefits of Phytates
On the flip side of this argument, since phytates are found in high fiber foods, it is thought that they may possess strong cancer suppressing activity as well. High fiber foods have shown protective benefits against a wide variety of cancers. In addition, phytates have shown some ability to suppress free radicals in the body. Some experts have suggested that the ability to complex iron may be the root of their function in this capacity.
Other suspected benefits of phytates include:
- Protective benefits against osteoporosis
- Protection from Parkinson’s disease
- Reduce inflammation in the body
- Reduce oxidative stress on the digestive tract
- Reduce depression
- Slows blood glucose response by slowing digestion
Reducing Phytates In Food
If you’re concerned about phytates in food, you may be gratified to learn that specific handling may drastically reduce their concentration in many foods. Options for reducing the concentration of phytates include:
- Using sprouted grains
- Baking
- Soaking them in water
- Fermentation
- Cooking
Even this subject bears some level of debate, as some proponents of consuming phytates suggest that cooking may simply free phytic acid from the indigestible portions of food, rather than degrade the phytate itself.
What’s The Bottom Line?
One interesting thing I’ve learned is that one reason many individuals cite for avoiding grains is the presence of phytates. Yet most proponents of grain-free diets also counsel in favor of consuming nuts and seeds, which we can see are much higher in phytates than most grains.
I can see both sides to this argument. I would certainly be concerned about phytates for malnourished or otherwise nutritionally compromised individuals. Everyone has to make up their own mind about this. Personally, since I don’t believe I fall into that category, I can’t say that I see a valid reason for avoiding phytates altogether. To learn more about eating Paleo, I’d suggest starting with The Paleo Diet
Resources
- Wikipedia
- Answers.com
- Phytochemicals.info
- Diagnose Me
- Photo credit: Peter Pearson
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The main reason I try and avoid grains is to control the hormone insulin. That’s same reason I try and avoid potatoes and too many legumes. I’ve never really considered phytates – but with all the almonds I eat perhaps I should look into it more…
I noticed in the part about the health benefits that almost all the research you quoted says things like that the research suggest they might fight cancer and that they are thought to fight cancer. Did you find any research that actually shows that the phytates have any true health benefits, besides what researchers think they might do?
David,
You’re right in that most of the research is suggestive, rather than definitive. That holds true for both negative and positive health effects. Unfortunately, most research of this sort is indirect, as doing direct comparisons requires strict dietary controls to be enforced. I think you’ll find the same sorts of problems if you start looking at research on antioxidants.
Very good point!
I think that is one of the most frustrating things about trying to eat better and lose weight. The primal diet guys seem to be in really good shape and have research that says they are right. Some vegans and vegetarians can say the exact same thing. They can not both be right. As I am trying to figure out the right way to eat and make life long dietary changes it is hard to know what path is the right one.
Maybe if you could get the major agricultural and pharmaceutical companies to stop funding the research we could actually learn something.
You’re right, of course. I think what can be derived from that is that there are many ways to skin a cat. What’s most important is to find something that works for you. If you hate meat, then no amount of research would make primal living a good choice. Conversely, if you love steak and are repulsed by tofu, then I doubt you would be successful at a vegetarian lifestyle.