In a previous article1, I suggested that nut consumption should be limited or moderated because of the high levels of omega-6 fat many of them contain. But there’s another reason you shouldn’t make nuts a staple of your diet.
One of the main principles of the Paleo diet is to avoid eating grains and legumes because of the food toxins they contain. One of those toxins, phytic acid (a.k.a. phytate), is emphasized as one of the greatest offenders.
But what is often not mentioned in books or websites about the Paleo diet is that nuts are often as high or even higher in phytic acid than grains. In fact, nuts decrease iron absorption even more than wheat bread2. This is ironic because a lot of people on the Paleo diet – who go to great lengths to avoid food toxins – are chowing down nut like they’re going out of style.
What is phytic acid and why should we care?
Phytic acid is the storage form of phosphorus found in many plants, especially in the bran or hull of grains and in nuts and seeds. Although herbivores like cows and sheep can digest phytic acid, humans canโt. This is bad news because phytic acid binds to minerals (especially iron and zinc) in food and prevents us from absorbing them. 3 Studies suggest that we absorb approximately 20 percent more zinc and 60 percent more magnesium from our food when phytic acid is absent4. It’s important to note that phytic acid does not leach minerals that are already stored in the body; it only inhibits the absorption of minerals from food in which phytic acid is present.
As most people following a Paleo diet will probably have heard by now, diets high in phytate cause mineral deficiencies. For example, rickets and osteoporosis are common in societies where cereal grains are a staple part of the diet.5
How much phytic acid should you eat?
Before you go out and try to remove every last scrap of phytic acid from your diet, keep in mind that it’s likely humans can tolerate a small to moderate amount of phytic acid – in the range of 100 mg to 400 mg per day. According to Ramiel Nagel in his article “Living With Phytic Acid”6, the average phytate intake in the U.S. and the U.K. ranges between 631 and 746 mg per day; the average in Finland is 370 mg; in Italy it is 219 mg; and in Sweden a mere 180 mg per day.
As you can see from the table below, 100 grams of almonds contains between 1,200 – 1,400 mg of phytic acid. 100g is about 3 ounces. That’s equal to a large handful. A handful of hazelnuts, which is further down on the list, would still exceed the recommended daily intake – and that’s assuming you’re not eating any other foods with phytic acid, which is not likely. Even the Paleo-beloved coconut has almost 400 mg of phytic acid per 100 gram serving.
[Disappointing side note for chocolate lovers: Raw unfermented cocoa beans and normal cocoa powder are extremely high in phytic acid. Processed chocolate may also contain significant levels.]
FIGURE 2: PHYTIC ACID LEVELS1
In milligrams per 100 grams of dry weight
| Brazil nuts | 1719 |
| Cocoa powder | 1684-1796 |
| Oat flakes | 1174 |
| Almond | 1138 โ 1400 |
| Walnut | 982 |
| Peanut roasted | 952 |
| Brown rice | 840-990 |
| Peanut ungerminated | 821 |
| Lentils | 779 |
| Peanut germinated | 610 |
| Hazelnuts | 648 โ 1000 |
| Wild rice flour | 634 โ 752.5 |
| Yam meal | 637 |
| Refried beans | 622 |
| Corn tortillas | 448 |
| Coconut | 357 |
| Corn | 367 |
| Entire coconut meat | 270 |
| White flour | 258 |
| White flour tortillas | 123 |
| Polished rice | 11.5 โ 66 |
| Strawberries | 12 |
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Can you prepare nuts to make them safer to eat?
Unfortunately we don’t have much information on how to reduce phytic acid in nuts. However, we know that most traditional cultures often go to great lengths prior to consuming them.
According to Nagel7:
It is instructive to look at Native American preparation techniques for the hickory nut, which they used for oils. To extract the oil they parched the nuts until they cracked to pieces and then pounded them until they were as fine as coffee grounds. They were then put into boiling water and boiled for an hour or longer, until they cooked down to a kind of soup from which the oil was strained out through a cloth. The rest was thrown away. The oil could be used at once or poured into a vessel where it would keep a long time.50
By contrast, the Indians of California consumed acorn meal after a long period of soaking and rinsing, then pounding and cooking. Nuts and seeds in Central America were prepared by salt water soaking and dehydration in the sun, after which they were ground and cooked.
Elanne and I have been preparing nuts like this for a few years, and I personally notice a huge difference in how I digest them. I used to have a heavy sensation in my stomach after eating nuts, but I don’t get that at all when I eat them after they’ve been prepared this way.
Another important thing to be aware of is that phytic acid levels are much higher in foods grown using modern high-phosphate fertilizers than those grown in natural compost.
So how many nuts should you eat?
The answer to that question depends on several factors:
- Your overall health and mineral status
- Your weight and metabolic health
- Whether you are soaking, dehydrating and roasting them nuts before consuming them
One of the biggest problems I see is with people following the GAPS or Specific Carbohydrate Diets, which are gut-healing protocols for people with serious digestive issues. Most GAPS and SCD recipe books emphasize using nut flour to make pancakes and baked goods. This is presumably because many people who adopt these diets find it hard to live without grains, legumes and any starch. While nut flours don’t tend to contain much phytic acid (because nut flour is made from blanched nuts, and the phytic acid is found mostly in the skin of the nuts), they can be difficult to digest in large amounts โ especially for those with digestive issues. I’ve found that limiting nut flour consumption is necessary for most of my patients that are on GAPS or SCD. It’s also best to be moderate with consumption of most commercial nut butters, which are made with unsoaked nuts. However, some health food stores do carry brands of “raw, sprouted” nut butters that would presumably be safer to eat.
All of that said, in the context of a diet that is low in phytic acid overall, and high in micronutrients like iron and calcium, a handful of nuts that have been properly prepared each day should not be a problem for most people.
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Re phytins in whole grains and particularly flax seeds: I like them freshly ground then added to very hot water, it makes a jello like substance to which it is easy to add flavoring either sweet or salty. Great to curb hunger and add some proteins and roughage in diet when doing a reduced carbo diet, master cleanse like.
If I understood properly the notes above, there are no issues if consumed separately from main meals – correct? Another question is, regarding minerals robbing/ binding property, would adding a dollop of a minerals rich supplement like molasses prevent these binding negatives?
If you have not by now…check out Nourishing Traditions, a cookbook by Sally Fallon. “Crispy nuts” recipes have you soak nuts in sea salt (Celtic Sea Salt brand, per my naturopath). Soak at least 7 hours or overnight (12 hours doesn’t hurt) in warm filtered water, in a warm place. cups nuts, 2 tsp sea salt, (also have seen 1 Tbsp sea salt per 1 litre water).
Drain, and rinse well – especially if you have digestive issues. Nuts can be eaten at this point or dried 12 to 24 hours in a dehydrator or warm oven (150F rcommended). Then store in airtight containter. I use mason jars.
Note that walnuts are to be stored in the fridge, before and after making crispy nuts. The oil in walnuts goes rancid if stored at room/warm temperatures.
Sometimes I soak just enough for the day, rinse and carry along in a container.
For digestive issues and picky eaters, the Gut And Psychology Syndrome book, diet and recipe book is very good as well.
Happy eating.
http://nutrevolve.blogspot.com/2013/11/omega-6s-and-inflammation.html
All of your referenced articles are at least 20 years old… I especially liked the claim that ‘nuts decrease iron absorption even more than wheat bread’ which you have based on a study done in 1988 on Indian women in a poor area that had iron deficiencies. The study also found that small quantities of vitamin C (found in many fruits and vegetables) overcame the effect of the lack of absorption of iron due to the addition of nuts in the diet. I guess you forgot to mention that bit.
I would be happy to re-evaluate, providing you use more up-to-date and less biased articles to support your claims.
Hi guys! I’m happy to read such an active and helpful forum. I’m having a hard time finding information on rinsing nuts and rice with food grade hydrogen peroxide. I’m concerned with molds that grow in non-ideal storage conditions. Does anyone have experience with hydrogen peroxide? Any time I soak/rinse rice or walnuts in hydrogen peroxide it foams up like a real bad infection. I’m not sure if this could be a reaction with anything else on the skin or if it does indicate mold/bacteria. Now I know some of those things might not actually need disinfecting but somehow I got the notion in my head that improperly dehydrated foods need to be sterilized before eating. Thoughts?
Oat in flakes are high temperature steamtreated(in Denmark, destoying the phyt-ase(enzym speeding up the breaking down of phytic acid) so
add some ryeflour or barley flakes(in Denmark not steam treated) to oat flakes and
soak for 6-8 hours may be more (after 20 hours it will turn acid, but beans should be soaked for 24 hours)
cooking maybe improve the result
beans soaked 24 hours
cooked aprox 45 min or 15min under pressure( 2 atomos = aprox 245 Fah
the minerals now as secundare fosfates may be sedimented , so let some water remain
en casa of Butterbeans (Limabeans cook without tap (and open window) and all water away)
Hi Chris,
I’m wondering if it’s necessary to soak oats or will phytates be reduced by simply cooking them? Thanks!
This is getting ridiculous. It’s getting to where EVERYTHING we eat is dangerous. EVERYTHING. If you google ANY type of food there is something about it that can cause harm. Just eat nothing. Sit in a closet and sip on water all day.
That comment made me laugh out loud. I couldn’t agree more. Just make sure that the water is filtered and sipped out of a glass or BPA free cup ๐
LOL
I concurr and then “poof”, within a few weeks you’re dead, problem solved!!! ๐
Great Article! Actually I’ve read Ramiel Nagel’s book, “Cure Tooth Decay” where he also addresses the phytic acid issue when it relates to acquiring enough minerals to help remineralize teeth. He also included some of his points on his website, here is the article:
http://www.curetoothdecay.com/Tooth_Decay/whole_grains_cause_tooth_decay.htm
The biggest problem is with the way we prepare (or don’t prepare) food for consumption these days. Legumes and grains were historically soaked for long periods of time before consumption. Instead of just avoiding all these foods, they should be incorporated into a healthy diet in which everything is prepared so that we can most easily digest and absorb the nutrients, which includes soaking legumes and grains overnight at the very least. Read Sally Fallon’s Nourishing Traditions for more information.
Interesting information. Might be my problem with almond flour baked goods. I can eat a handful of raw almonds but if I have roasted almonds or any baked goods with almond flour, I have a reaction, mild but still a reaction.
I have started the GAPS diet and am wondering/concerned with amount of nuts/seeds it recommends? I am getting confused and overwhelmed with all this info. I am also very underweight and don’t know how the best way is to gain weight on the GAPS as it is so carb limiting. What do you recommend for your clients that you put on GAPS, what does your version of the GAPS diet look like? What would you suggest for weight gain on your version of the GAPS?
When I keep my carbs lower, I tend to crave and feel addicted to nuts- any reason for that? Also, if I prefer to just eliminate them, are there nutrients I would have to “make up” another way? I just always hear so healthy they are that part of me is afraid to give them up. Thanks!
Jill–I too find that now that I’ve cut sugar out and lowered carbs I have a nut addiction. I feel driven to eat them in large quantities and have that “can’t stop myself” feeling. I’ve always loved nuts, but this powerful craving is new and feels detrimental to my progress. I’m also wondering if there is something less “addictive” I can substitute for nuts.
If you eat a balanced diet, i.e. meat or vegetables or milk, you can eat as many nuts as you want without worrying about phylate. The amount of ion phytate chelates is insignificant compared to the amount of ions you ingest. Also you digestive system contains phytase which breakes down phylate to phosphate. Only creatures that should be worreid about phylate are cattle and feed animals because their diet comprises soley of seeds and distiller grains. I ran into this article while researching phylate uses in fertilizer, and found many anti nuts articles. These are all bullshit. Don’t know who Chris Kesser is but he is no chemist. Alot of doctors have a startling deficiency in basic inorganic chemistry.
I am admittedly a “health nut” but not persuaded about the phytic acid thing–this seems all too speculative and theoretical despite some studies. Too many other studies show that nuts are powerfully preventive against heart disease, diabetes and other maladies. If you eat a balanced diet of healthy, natural foods and take supplements, nature has a way of negating and cancelling out the supposed downsides of certain foods.
I am with you Ed. You can get all the anti-cancer and heart healthy benefits of nuts, legumes, and whole grains by eating them with absorption promoting foods like garlic and increasing your intake of other nutrient dense foods like leafy greens and berries. The risk is really inflated here and the benefits of these foods are dangerously downplayed. If you want to look at the nutritional science check out Dr. Greger’s video: http://nutritionfacts.org/video/new-mineral-absorption-enhancers-found/.
I just read that phytic acid is found in the HULLS of nuts and grains. So, if a nut is hulled or a whole grain is polished, for example, then they would not contain phytic acid?
That is correct, and it’s one reason I think white rice is generally well-tolerated. It’s mostly starch.
So if I prepare 100 grams of black beans by soaking and sprouting them, which helps get rid of the anti-nutrients (although not completely) that would be better for me then grabbing 100 grams or actually less since they are higher than 100 grams of refried beans, to eat? This is more for my son who is 23 months and the only Paleo “safe” carbs he can eat are sweet potatoes, all the rest constipate him. He can’t eat white rice either for the same reason. I am kinda out of Paleo carb options for him, although he really loves his sweet potatoes. ๐
Hi,
can you reveal the source of the “Phytic acid levels” list?
Jan
Does the drying/dehydrating/roasting step reduce phytic acid or is it simply for storing purposes and to improve the nut’s texture? I was previously adding a handful of raw nuts to my shakes but have stopped since I wasn’t soaking them.
I’d like to start adding them again but straight from the jar after they’ve soaked and into my blender.
It reduces phytate significantly in most cases.
Thank you Chris!
I eat quite a lot of nuts as do one or two of my clients. Not only that I also drink a lot of cocoa through the day. As both these foods are very high in phytates I have been interested to research the effects of phytates on health.
I came to the conclusion that phytates were unlikely to cause harm for most people unless they were predisposed to deficiency in the key minerals that phytates bind to, such as magnesium. The problem is mostly one for the third world where a dietary staple may contain a lot of phytate and perhaps not a lot of the key minerals to which it binds.
It is interesting and perhaps unsurprising on reflection, that the very mineral bound to so strongly by phytate is often present in large amounts within foods such as nuts, seeds and cocoa. Magnesium being a prime example.
I wrote my own article on phytate for which I have used Chris K among the sources. http://www.drdobbin.co.uk/phytates.
Hi All,
Great article ๐
I was wondering (not good!) ….. ok ‘pondering’ on going through a process of soaking for 18-24 hours on all nuts / seeds and then roasting enough so that this only needs to be done once a month!! What are peoples view on this?? It would certainly be much more cost and time effective?? Responses are eagerly anticipated and gracias in advance ๐ Seren