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 can’t. 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 – 1400 |
| Walnut | 982 |
| Peanut roasted | 952 |
| Brown rice | 840-990 |
| Peanut ungerminated | 821 |
| Lentils | 779 |
| Peanut germinated | 610 |
| Hazelnuts | 648 – 1000 |
| Wild rice flour | 634 – 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 – 66 |
| Strawberries | 12 |
Like what you’re reading? Get my free newsletter, recipes, eBooks, product recommendations, and more!
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 — 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.
Better supplementation. Fewer supplements.
Close the nutrient gap to feel and perform your best.
A daily stack of supplements designed to meet your most critical needs.
Here’s another view point on phytates: http://donmatesz.blogspot.com/2011/10/phytate-facts.html
This is a very interesting article. I’d love to hear what Chris has to say about that.
Maybe have almond milk instead of almonds…
Unsweetened almond milk contains 35 calories. 1 ounce of whole almonds contains 169 calories and about 22 almonds.. hence a cup of commercial almond milk contains about 5 almonds and about 100 mg phytic acid – well within the toleration range. You could have 4 cups a day and still be at 400 mg phytic acid.
Unsweetened almond milk (from the store) – along with most of the nut and seed milks – contain carageenan, which has been linked to cancer and inflammatory bowel disease. If you consume nut milk, it should be homemade.
The silk brand I use does not contain carageenan, but thanks for the information, good to know.
There is an update to the WAPF article on coconut flour:
COCONUT AND PHYTIC ACID
I’m writing in regard to the article written by Ramiel Nagel titled “Living with Phytic Acid” (Spring 2010). In the article there are references to the phytic acid content of coconut. Since the publication of this article people have been asking me whether they should soak coconut or coconut flour to reduce the phytic acid.
Phytic acid occurs in nuts and seeds in two forms—phytic acid and phytic acid salts [Reddy, NR and Sathe, SK (Eds.) Food Phytates. CRC Press, 2001]. Both are generally referred to as “phytates.” Together, these two compounds make up the total percentage of phytates reported in various foods. However, they do not possess the same chelating power. So the chelating effect of the phytates in corn, wheat, or soy are not the same as those in coconut. You cannot predict the chelating effect based on total phytate content alone.
The mineral-binding effect of the phytates in coconut is essentially nonexistent. It is as if coconut has no phytic acid at all. In a study published in 2002, researchers tested the mineral binding capacity of a variety of bakery products made with coconut f lour. Mineral availability was determined by simulating conditions that prevail in the small intestine and colon. The researchers concluded that “coconut flour has little or no effect on mineral availability.” (Trinidad, TP and others. The effect of coconut flour on mineral availability from coconut flour supplemented foods. Philippine Journal of Nutrition 2002;49:48-57). In other words, coconut flour did not bind to the minerals. Therefore, soaking or other phytic acid-neutralizing processes are completely unnecessary.
Soaking has been suggested as a means to reduce the phytic acid content in grains and nuts. Some suggest coconut flour should also be soaked. To soak coconut flour doesn’t make any sense. The coconut meat from which the flour is made, is naturally soaked in water its entire life (12 months) as it is growing on the tree. To remove the meat from the coconut and soak it again is totally redundant. After the coconut meat has been dried and ground into flour, soaking it would ruin the flour and make it unusable. You should never soak coconut flour.
In the tropics coconut has been consumed as a traditional food for thousands of years. Those people who use it as a food staple and regard it as “sacred food,” do not soak it or process it in any way to remove phytates. It is usually eaten raw. This is the traditional method of consumption. They apparently have not suffered any detrimental effects from it even though in some populations it served as their primary source of food.
Bruce Fife, ND
Colorado Springs, Colorado
If anyone would like a comprehensive amount of research data on the efficacy of coconuts and health:
http://www.coconutresearchcenter.org/research-link.htm
Very informative and well referenced.
Oh crap.
I drink coconut milk (aroy-d … two ingredients … coconut & water) and just ordered some coconut manna.
One of my favorite snacks is Greek yogurt with cocoa powder mixed in.
I am sad. 🙁
I guess this includes Artisana coconut butter? Yikes, that really hurts.
Needless to say, absorption IS promoted with supplementation and/or diet:
“Absorption and excretion of orally administered inositol hexaphosphate (IP6)”
“A study of the pharmacokinetic profile (oral absorption and renal excretion) of inositol hexaphosphate or phytate (IP(6)) is presented. Seven healthy volunteers were following a IP(6) poor diet (IP(6)PD) in a first period, and on IP(6) normal diet (IP(6)ND) in a second one. When following the IP(6)PD they become deficient in IP(6), the basal levels found in plasma (0.07+/- 0.01 mg/L) being clearly lower than those found when IP(6)ND was consumed (0.26+/- 0.03 mg/L). During the restriction period the maximum concentration in plasma were obtained 4 h after the ingestion of a single dose of IP(6), observing almost the same renal excretion profiles for the three different commercial sources and doses. After the IP(6) restriction period, volunteers were on IP(6)ND, reaching normal plasma and urinary IP(6) values in 16 days. Thus, the normal plasma and urinary concentrations, can be obtained either by consumption of a IP(6)ND taking a long time or in a short period by IP(6) supplements
I don’t think phytic acid (IP6) is problematic with proper nutrition and supplementation. Its also everywhere, so if you plan to eat plants at all, you will have to live with IP6 ‘horros’
First, the action of IP6 should be viewed related to sex. There is evidence that iron should be kept on lower levels high enough not to case anemia. For pre-menopausal females chelating of iron may not be good idea.
Now, instead of reiterating all this, here are sequences from the paper “Phytate: impact on environment and human nutrition” which summed it up nicely. So, I will keep my IP6, thx 🙂
——————-
Ascorbic acid and meat can to some extent reverse the inhibition of iron absorption by IP6. In presence of excess phytic acid, formation of soluble complexes between PA and a metal ion displaying 1:1 stoichiometries predominates. However, when metal ions are in excess, an insoluble solid
called phytate is formed .The pH is another factor influencing the solubility of phytic acid (Cheryan, 1980).
Phytic acid accumulates during seed development until the seeds reach maturity and accounts for 60%~90% of total phosphorous content in cereals, legumes, nuts and oil seeds (Lott et al., 2000; 2001).
It is however found in most eukaryotic tissues, where it is kept adherent to the cell walls through phosphoinositides, or in complexes with proteins or ions (Torres et al., 2005; Veiga et al., 2006). Phytic acid is found in ten-fold higher concentrations in the brains of rats as in the kidney, indicating that it has great potential outside the plant kingdom. In eukaryotes in general, three main features of PA keep it involved in a number of metabolic processes: its chelating properties and its ability to function as a phosphate donor/acceptor makes it ubiquitous/abundant in numerous cell systems. Moreover, the lower inositol phosphates are involved in a number of cell signalling pathways.
In mammalian organisms, PA has been implicated in starch digestibility and blood glucose response (Lee et al., 2006), in the prevention of dystropic calcifications in soft tissues (Grases et al., 2004)
and kidney stone formation (Grases et al., 1998; Selvam, 2002), and in the lowering of cholesterol and triglycerides (Jariwalla, 1999; Onomi et al., 2004).
PA has also been suggested to be part of a structure that could inhibit transcription of the viral genome from HIV-1 (Filikov and James, 1998), and apparently it has been tested in toothpaste as a tool for
preventing plaque formation. At the cellular level, PA or inositol phosphate intermediates are involved in gene regulation, efficient export of mRNA, RNA-editing and DNA repair (York et al., 1999; York, 2006). The lower inositol phosphates such as Ins(1,4,5)P3 take part in cell signalling cascades (Berridge and Irvine, 1989) and pathways leading to versatile functions within Ca2+ mobilisation and signalling (Efanov et al., 1997; Larsson et al., 1997). They also contribute to protein folding (Macbeth et al., 2005) and trafficking (Shears, 2004), endo- and exocytosis (Efanov et al., 1997; Saiardi et al., 2002), oocyte maturation (Angel et al.,2002), and cell division and differentiation (Berridge and Irvine, 1989)
Hi Chris! I found this great article and breakdown re nuts, PUFA’s, Omega 6’s and Phytic Acid. Although he says macadamias are very low and of no concern due to their PUFA being very low and most of their fat being monounsaturated that the Omega6/Omega-3 ratio is not a concern even in high amounts. He says they are also very low in phytic acid but does not give a level. I sent him a request for the phytic acid level on his FB page to see if he knows. Here is the link:
http://paleodietlifestyle.com/are-nuts-and-seeds-healthy/
Why do almonds need to be dried after soaking? Could they go straight from soaking to roasting?
You can get more information from the website lowoxalate.info. There is also a very active Yahoo forum, Trying_Low_Oxalates. Members include people with kidney stones, fibromyalgia, interstitial cystitis, vulvodynia, and parents of autistic children. Fibromyalgia seems especially responsive to a low oxalate diet; my fibromyalgia is almost nonexistent after eighteen months of low-oxalate diet, and other list members have similar results. Oxalates can collect in muscles, bones, organs, and endocrine glands, when the body does not have enough capacity to excrete them. This capacity varies widely between individuals, which is why some people can eat spinach, chocolate and a boatload of nuts without symptoms, and others end up with stones, rashes, and pain syndromes. Celiac disease and leaky gut predispose people to oxalate problems.
Chris,
I can’t help wonder, given many of the replies, whether this useful bit of knowledge did more damage psychologically than helped biologically 🙂
You can buy them roasted, though personally I stay away from roasted nuts as I don’t think it does the oils much good. Otherwise raw. I buy mine from the healthfood store but you may have to search online. Even our UK supermarkets do them! Not sure if you can get them routinely in the US?
What is the right type of Macadamia nut, i.e., toasted? salted? flavored? raw? in the shell?… and where on earth can you buy them?
Nuts are also very high in oxalates, which can be a significant problem for many people. When the body’s ability to dispose of oxalates is compromised due to leaky gut, stress, lack of minerals in the diet, or hormonal differences, it can build up many places including muscles, bones, and endocrine glands. This contributes to a number of pain syndromes, such as fibromyalgia. Oxalates are also a reason why those universally-acclaimed leafy greens might not always be the best choice for health.
Hmm. That’s interesting. I have been told I probably have leaky gut, and I have had multiple oxalate kidney stones in the past (granted.. pre-paleo). I wonder if oxalates ar contributing to the odd pain I have felt in my chest for months. It is still present, and I am at a loss for how to combat it.
Universally-acclaimed leafy greens? What are you smoking? Our species has survived all this time on what exactly? water? beef? While the Paleo diet might not be the best choice. I have found myself feeling TONS better when I incorporate more greens in my diet, less fruits and less foods that raise the acid in my body. There’s a thing called balance. We can just mow down on nuts and beef. I’m sure the nutritional benefits of the nuts if eaten in “moderation” would outweigh the anti-nutrients. Too much of anything is bad for you. It’s about a “balanced” diet. The modern Paleo diet doesn’t exactly work because people that lived in the Paleo time ate based on instincts and what was available. People today don’t eat based on instincts. They eat based on government commercialization and what “they” think we should eat. caveman didn’t eat cereal! While cereal in small amounts occasionally would be okay. it shouldn’t make up the bulk of our diet. You can get good carbs and fibre from other foods.
Macadamias and chestnuts have a good profile even without soaking- v low in phytates and PUFA
If I don’t soak macadamia nuts they give me a sore stomach that comes back every time I eat anything for the next couple of days. So maybe it’s the lectins?
I read that most of the phytic acid in almonds is found on the skin, and therefore when it’s removed (say to make almond flour) that it’s actually fairly low in phytic acid. Unfortunately I wasn’t able to find much research on this, so I don’t know if it’s true or not. Any idea?
Wow. This just blew my mind. I couldn’t figure out why I was still being diagnosed as a “functioning anemic” in spite of a paleo-friendly diet, including loads of red meat, PLUS iron supplementation (I had even started digestive enzymes, thinking there were issues with digestion). But I am a nut addict, and therein lies the problem! I am going to reassess my diet, trying to minimize (not eliminate…a girl needs her dark chocolate. Ha.) my phytic acid intake, and reassess after 30 days. Thank you for the work you do, and for your balanced approach to nutrition (and life!).
in this post: “Even the Paleo-beloved coconut has almost 400 grams of phytic acid per 100 gram serving. ”
I have to assume you meant 400 mg. Right?
I am currently on the GAPS diet and I prepare nuts by soaking in whey (from homemade yogurt) for 12-24 hours, draining and then dehydrating in a cool oven. I not only find that they are MUCH tastier this way, but far easier to digest. If I want to use nut flour in an occasional treat, I will grind my own, properly prepared nuts rather than buy store-bought nut flour.
Thanks for this, Chris. I really wish the USDA would quit spending our money telling us what to eat, and put it instead into telling us what we ARE eating. Their nutrition database is in need of serious improvement, and it wouldn’t hurt my feelings any if they added phytate numbers to their food listings as well.