Nuts and Phytic Acid: Should You Be Concerned?
Who doesn’t like nuts? They’re crunchy, fatty, nutritious, and convenient. They travel well. Tossing them into the air and catching them with your mouth is a fun way to impress any onlookers (this effect is enhanced if you sit in a chair backward at the same time). They even turn into butter. Nuts are the common bond between all dietary sects, it seems. Vegans love them for the protein. Ancestral eaters accept them, some begrudgingly. Weston A. Pricers have to soak, sprout, dehydrate, and ferment them before they’ll even consider eating nuts, but in the end, they love them. Mainstream healthy dieters dig their “healthy fats.” Epidemiologists, squirrels, and birds laud them. They’re self-contained little morsels of instant edibility, good raw and roasted alike. What’s not to like?
Well, there’s the phytic acid. Wait – isn’t that the stuff you find in grains and legumes? Yes. Should we be concerned? Let’s take a look…
Hi Mark,
I was hoping to get your take on phytic acid in nuts. If nuts are so good for us, and beans and grains so bad, but all three contain a good amount of phytic acid, what’s the deal?
I like nuts. I guess what I’m really asking is: can I still eat them?
Thanks,
Cindy
Yes, it’s true. Nuts contain a lot of phytic acid, AKA phytate, AKA IP-6, AKA the storage form of a plant’s phosphorus, and antioxidant to the seed in times of oxidative stress (PDF). When something that contains it is eaten, phytic acid binds to minerals like zinc, iron, magnesium, calcium, chromium, and manganese in the gastrointestinal tract, unless it’s reduced or nullified by soaking, sprouting, and/or fermentation. Bound minerals generally cannot be absorbed in the intestine, and too many bound minerals can lead to mineral deficiencies. Animals who produce phytase – the enzyme that breaks down phytate – can thrive on phytate-rich foods. Rats, for example, produce ample amounts of phytase and can handle more dietary phytate without exhibiting signs of mineral deficiencies. Since humans produce around 30 times less phytase than rats, phytate-heavy diets might be problematic for humans.
By dry weight, nuts generally contain more phytic acid than similar amounts of grains and legumes. If you don’t believe me, take a look at this table, pulled from Chris Kresser’s excellent article on phytic acid in nuts:
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
So, 100 grams of almonds has between 1138 and 1400 mg of phytic acid. Walnuts have 982 mg, and 100 grams of Brazil nuts tops the list with over 1700 mg!
Meanwhile, 100 grams of brown rice has between 840 and 990 mg, lentils have 779 mg per 100 grams, and oats contain just over 1100 milligrams.
So what’s the deal? Why do nuts get a pass, while grains and legumes get condemned?
First of all, grains and legumes are generally seen as dietary staples. They form the foundation of meals. People don’t have a “small handful” of refried pinto beans (and not just because that’s an incredibly messy way to eat them) or “one or two” grains of brown rice. They eat plates of this stuff, they rely on them for protein and calories, and sure enough, cultures whose diets are based on (improperly prepared) grains and legumes often suffer the symptoms of widespread mineral deficiencies, like nutritional rickets.
Nuts, on the other hand, are an adornment to a meal or a snack in between. A condiment. They are not meals themselves. And though I hear stories of people going Primal and subsequently going crazy with nuts, eating almond flour bread with every meal and downing a pound of pecans each day, I just don’t see it. I could be mistaken, of course. If I am wrong, and you guys are indeed eating large quantities of phytate-rich nuts every day, don’t do that. Keep it to about a handful (which is between one and two ounces, depending on the hand) per day. But my general sense is that people aren’t eating copious amounts of nuts. They’re eating some nuts in between meals, on those days when they just need a snack. They’re making almond meal pancakes once or twice a month (cause let’s face it – they’re kind of a drag to make and clean up after).
It’s quite telling that all the studies looking at the effect of phytate on mineral bioavailability focus on grains and legumes, not nuts, because grains and legumes are what people are actually eating and relying on for nutrients. In 2007, the average American ate 610 grain calories and just 89 nut calories per day. I strongly suspect those numbers would look a little different for a Primal eater, but my point stands: you don’t see any studies examining the effect of almond intake on mineral bioavailability because nobody’s relying on almonds for their nutrition.
Second, those figures are for “phytate per 100 grams dry weight.” 100 grams of almonds is a little different than 100 grams of brown rice in the real world, on your plate, and in your mouth. The brown rice is about 362 calories, while the almonds are 575 calories. You’re far more likely to plop 362 calories of brown rice onto a plate and go back for seconds than you are to eat almost an entire cup of almonds in a sitting. 100 grams of rice is a standard meal; 100 grams of almonds is veering out of “snack” and into “meal” territory.
Is there an “ideal” way to eat nuts with respect to the phytic acid content?
Although asking “What would Grok do?” doesn’t give us definitive prescriptions for what we ought to do, it can be a helpful starting point. How would our ancestors have eaten nuts? By the plastic shrinkwrapped pre-shelled and salted bagful? Or by the laboriously gathered and hand-shelled occasional handful? Eating nuts is effortless now, but it wasn’t always like that. Ever crack a macadamia shell by hand? A Brazil nut? An almond? It’s hard work. You’re either trying to break open a rock-hard shell or sifting through fragments of shell and nut to find something edible. If you eat your nuts like you had to gather and shell them yourself – rather than gorging on them by the handful – you won’t be able to consume a significant amount of phytic acid.
If you’re still worried about phytic acid from nuts, you can play around with food timing. In order for phytate to impair absorption, it has to physically come into contact with the minerals in question. Since mineral absorption – or non-absorption caused by phytate chelation – happens in the gastrointestinal tract, that wild and crazy place where masticated and partially digested food particles gather, mingle, and sometimes pair up, keeping the food in your gut away from the phytic acid in your gut by eating the nuts separate from other foods might improve your mineral status. The minerals in the foods with the phytic acid will presumably be affected, but the impact on other sources of minerals should be reduced. Eat your nuts apart from other sources of minerals. Sorry, those Brazil nut-crusted oysters, while delicious, might be a bad idea for zinc absorption.
This is in stark contrast to the way most people eat their phytate. The average person out for Mexican food, who eats grains and legumes with relish, is having four corn tortillas (448 mg phytate) with a small scoop of refried beans (622 mg) and some brown rice to, ya know, be healthy (990 mg). He throws in a few hefty slices of carne asada, but the combined 2060 milligrams of phytic acid for that meal will impact its overall mineral contribution.
The average Primal person, who avoids grains and legumes, has an ounce, or a small handful of almonds as an afternoon snack (350 mg phytate) with a couple Brazil nuts (171 mg) for the selenium. Being snacks, they’re separate from his meals. Being separate from his meals, the antinutrient effect of the phytate on the other minerals is lessened. If he bumped that up to 100 grams of each nut for over 3000 mg of phytate and over 1200 calories, then, yeah, he’d have a phytate problem (and an omega-6 problem). But he’s not doing that.
Unless you’re a Hadza, you shouldn’t be relying on nuts for the bulk of your nutrients and calories. And that’s the important thing: you don’t have to, nor are you compelled to, because the Primal eating plan is an overall nutritious one, full of mineral-rich vegetation, animals, and yes, the occasional handful of nuts. You’re not relying on plant foods for your zinc – you’re eating shellfish and beef and lamb for the far-more-bioavailable animal-based zinc. According to the evidence I was able to find, phytic acid simply isn’t a major concern in the context of a nutritious diet, especially one that contains ample amounts of animal-based minerals and protein.
Besides, you wouldn’t want to completely eliminate phytate from your diet, even if it were possible. There are a number of possible beneficial health effects of a moderate amount of phytic acid which I’d be remiss if I didn’t mention, like:
- Phytic acid can inhibit calcium crystallzation and reduce kidney stone development.
- If you have hemachromatosis – a tendency to absorb too much iron – you actually want to reduce your iron absorption, and dietary phytic acid can (famously) do just that. It’s also one of the only iron chelators that does not induce lipid peroxidation or the formation of reactive oxygen species (PDF). If you’re trying to absorb more iron – maybe you’re pregnant or anemic – taking some vitamin C with the phytic acid will inhibit its iron-binding ability (PDF).
- Phytate may also be an effective anti-cancer agent with the curious tendency to ignore the healthy cells and focus only on the cancerous ones.
So to answer your final question, yes, I’d say you can definitely eat and enjoy nuts in moderation, an ounce or two (especially soaked) as long as you’re eating an otherwise nutrient-dense diet.
Which you are, right?
Thanks for reading, everyone. Be sure to leave your thoughts in the comment section.
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Posted By: Mark Sisson
A bit of phytic is probably not a big deal in a nutrient dense environment. As long as you are getting twice as much iron and what not than you need, then the phytic is not going to be able to put a dent in that. I think the phytic really comes much more into play when people are already eating nutrient poor borderline diets when further loss of nutrient absorption becomes a serious blow to an already serious deficiency. However, one other concern for nut consumption might be the potential for them containing a lot of rancid PUFA.
Glad someone finally mentioned the fat issue. Rancid or not, shouldn’t we be keeping the omega-6 fats down? I’ve been eating a ton of nuts (more than a cup a day) over the last year or two, and have just recently decided to get that down to about a handful or so, with emphasis on macadamias.
An ounce or two a day and you’ll be getting around 4 -7 grams of omega-6′s, which should balance out nicely if you are including a few cuts of fish a week.
Dangers of omega 6′s become present when the n-6 to n-1 is about 10:1 or greater. I’m not saying any lower than that is optimal, but it’s certainly not enough to be fearful of nuts. Some people in the Paleo world take the fear of n-6 a little too far.
Even if you are eating a cup a day that’s only 15-18 grams of n-6, which if you are eating fish a few times a week would probably put your ratio around 4:1, which is pretty good, IMO.
However, I find that the real danger in nuts, is the calories. These things pack calories and they are not satiating for the calories. Eating around a cup a day is more than 800 calories. By comparison, you could eat ONE POUND of grass-fed beef to get that many calories.
http://nutritiondata.self.com/facts/beef-products/10526/2
A cup doesn’t even look like that much, and most people wouldn’t even start to feel full after that.
Nuts are an issue for most of my clients trying to lose weight, I believe, because they are so deceptively calorie dense.
I think that if calories are an issue then they are mostly an issue of competition in which fat you are burning–the fat from your food or the fat you are taking out of your storage reserves. But I am not sure how that works. I know that once you turn your fat into ketones there is no way to turn them back into fat; either you are going to burn them or you are going to excrete them in some way. (This is the “metabolic advantage” that Atkins dieters sometimes talk about.) But the info I hear about how this works is never consistent. Some folks say you need to eat more fat to further encourage fat-burning; others say you need to cut back even though they’re not low-fat ideologues.
That said, I wonder if your clients have looked at their overall micronutrient intake. You can’t expect a metabolism to work properly if you’re trying to cut your calories to the bone and are taking cheap supplements on top of it where you are taking any supplementation at all. I’ve gotten a little “push” just from adding things like K2 and choline into my regimen. K2 is known to increase insulin sensitivity by its action of contributing to osteocalcin production (true story, I’ve run into the research abstracts online); choline is known to treat fatty liver disease which also helps with metabolism and fat loss. Just two examples. And I see almost no one ever looking at this.
I’m glad I’m reading that because I tend to over-indulge with nuts, thinking: “it’s alright, it’s primal anyway”.
Very helpful!
I’ve taken recently to eating a small handful of walnuts for breakfast (around 10ish). Easy to do at work, I get in regular 16 hour fasts, and that holds me through meetings until lunch. Glad to hear that eating them on an empty stomach may avoid the mineral absorbtion problem. Forgot about the soaking part tho…
Dr. Richard K Bernstein says when his patients are having trouble getting blood sugar down to normal values, it is often nuts that are causing this derailment.
I have diabetes and have noticed a drop in blood glucose when I don’t eat nuts. And they taste so good
I find nuts are insanely filling , have you ever eaten a handful of “plain” nuts and thought OMG I’m starving?
Not counting “seasoned” nuts because those are designed to make you eat more.
Raw cacao, macadamia, jungle peanuts, ramon nuts, and coconut meat in the protein shakes; coconut manna by the occasion teaspoon during the day. No issues.
Don’t throw nuts in the air and catch them with your mouth in front of children. It’s a choking hazard for small kids, and maybe for adults as well.
What if they wear a helmet?
lol, with a face mask
Unfortunately, eating nuts has the same effect on me as eating beans and whole grains. It feels as if I swallowed pins and needles.
To those comparing small quantities of nuts to beans… I thought one of the main reasons for avoiding beans (legumes) wasn’t just the phytic acid, but the lectins which bind to intestinal walls and cause gut damage/inflammation. My understanding is that nuts do not contain these harmful lectins?
Nuts do contain lectins.
A search on “leaky gut” and “phytic acid” gets many hits. It would appear that phytic acid by itself could cause a leaky gut.
There are all sorts of lectins, both harmful and harmless. A lectin is simply a protein molecule with a sugar molecule tacked onto one end. They cause problems when they behave like antigens and latch onto your cells but not all of them do that.
I wouldn’t be surprised if nuts have some that can cause issues in large amounts, though. Think about it–they’re seed foods, basically the nut tree’s babies. A nut tree can’t maul you to death like a mama bear, so she’s got to hit you through chemistry.
AWE NUTS! I probably eat too many nuts. They have become a staple snack for me and I eat them almost daily. I have Almonds, Cashews, Walnuts and sometime Macadamia Nuts in my desk at the office. Guess I need to pull back a bit from these. UGH. Good post though! THX
I suffered IBS symptoms nearly every day for as long as I can remember and it’s only recently that I realized that nuts are one of the contributing factors. I can’t even eat a tablespoon of them without getting doubling-over intestinal cramps the next day.
So for me, nuts are categorized right in with grains and legumes, as things with a shell that make my belly hurt.
Great point about actually having to crack/de-shell nuts before eating them. This would also cause you to feel the effects of satiety as you are slowly working to de-shell these balls of butter, as opposed to throwing a handful down your gullet and bypassing the onset of satiety. However, it’s a hell of a lot easier to find de-shelled nuts than shelled varieties these days. I just avoid them altogether…too expensive for the most healthful varieties, aka macs
I’m going to have to vehemently disagree with the statement “Nuts are not meals themselves.” Anyone who states this has never had a package of Trader Joe’s Sweet and Spicy Pecans. I could seriously die eating these… and I very well may!
Nuts are so dangerously addictive! Seems to be the case for so many of us. Fresh homemade almond milk I have found a little easier to tolerate. I just posted a recipe for that today.
Blanched almonds I imagine have negligible amounts of phystc acid. Don’t most of the phytates remain on the skin?
This is a timely post for me. I LOVE nuts and eat them regularly – probably more than usual since I went primal one month ago. Here is another reason to keep an eye on nut consumption, especially for cold sore sufferers: nuts are high in the amino acid arginine. I picked up that lovely virus on my hand somehow a few years ago. I get a painful recurrence regularly, almost monthly, especially when I don’t take my VERY expensive anti-viral medication. I got one last week (and was out of my medicine), so I started researching whether there is a dietary link to cold sores. As it turns out, a lot of people recommend a diet which is relatively higher in the amino acid lysine and lower in the amino acid arginine. I found this chart which compares the two for those who might also suffer from this lovely virus (nuts are at the wrong end of the chart): http://www.sandiegohomeopathy.com/downloads/Lysine_Arginine_Foods.pdf
I have also started a Lysine supplement. It seems to be doing the trick while I wait for my anti-viral meds to arrive in the mail. Funny, my doctor didn’t tell me to watch what I eat – he just prescribed this medicine I’ve paid a ton for over the past several years.
Dear Mark –Thanks for the suggestion of eating nuts separately from meals wherein you’re concentrating on getting your mineral intake (and absorbtion). I am one of those who goes way overboard on the nut butter. Though I am working on reducing the amount I’m consuming, I think that ensuring my mineral intake is high at my regular meals and the nut and nut butter consumed at snack time will help reduce the likelihood of losing the minerals. I hope that’s the case… I’ll stay tuned-in.
Note: a recent blood test showed normal mineral levels, so even with my moderate-to-high intake, I must be timing it pretty well already.
Oh my. I just started this way of eatting two weeks ago and have been eating a tin of nuts as I hate to stop and eat and rely on nuts throughout the day for snacking. I also made a great “granola” with nuts and coconut oil roasted in the oven and eat it with whole milk yogurt for breakfast. I have to rethink my menu big time!
I relied heavily on nuts and nut butters and almond flour when I first started eating this way. I’m only a few months in and am still using them semi-regularly. If I tried to go 100% pure from the start, I never would have made it.
If you’re just starting out, even eating a lot of nuts is probably a better change from what you were doing a few weeks ago!
I think everyone is completely overreacting to eating too many nuts. I live primal for the most part and if I want 2 handfuls I’m not going to sweat it. Interesting article.
Question … I thought that if I include nuts in my salad that it is supposed to help with nutrient absorption … is this not true?
Olive oil will help with absorption too. Fats in general, really.
Great post!!!
I eat nuts in a smoothie for breakfast.
1/2 (small handful) pecan, 1/2 Macadamia Nuts.
2 table spoons Coconut oil
15 or 20 blueberries and almond milk as the fluid.
My question(s) – I don’t see Mac nuts listed? Any comments about them?
And – soaking them for how long to remove the baddies?
I’m with the Weston A Price group on this one – soaking the nuts overnight with a little salt eliminates most worries of phytic acid and doesn’t greatly affect the taste, nor does it take much time. Just soak and enjoy, it is the best of both worlds.
Your point about them essentially being a condiment is spot on, though. If your nut consumption (including butters ndobedient baked goods) is really only an ounce or two per day, no
hmm, I make myself a almond pancake almost every morning for breakfast… perhaps I should soak the almonds first before using them?
Almond flours are ridiculous, and akin to vegans eating “meat substitutes”. Almond flour has the skins removed, which is where all the anti-oxidants in almonds are found. Again, almond flour is silly.
A better alternative, if you can’t give up “grains”, is soaked, sprouted, fermented buckwheat. This eliminates almost all of the phytic acid. The sprouting increases vit c, vit e, beta-carotene.
Makes good waffles, pizza crust, soft tacos, etc.
I don’t fuss about antioxidants when I am eating food. I’m more interested in the mineral content of nuts than I am in the antioxidants. My bones will not fall apart without antioxidants, but they will if I don’t get my minerals.
Nut flour isn’t remotely like fake meat. Flour is a plant-based food; nuts are plant-based foods. Not much of a stretch and if you look to traditional cultures you will find that several of *them* have made nut flours as part of their traditional cuisine. For example, several American Indian cultures used acorn that way.
Vegan fake meat on the other hand is not at all animal based and is contrived from stuff that has nothing to do with animal foods. Huge difference.
How do I tell if almonds are rancid? I buy 3 lb. bags of Member’s Mark California whole almonds (already shelled and not salted) from Sam’s Club but they don’t say on the bag whether they are roasted or pasteurized. They always look and smell fine (very little if any smell). The expiration date is about 6 months out.
Buddy,
100% of almonds sold in this country, unless bought locally directly from a farmer, are pasteurized either by propylene oxide or steam.
Both of these processed actually increase some anti-oxidant properties. I haven’t found literature addressing the potential for steam pasteurization to effect the PUFA, but I would think that it would.
As of 2007, and a couple salmonella outbreaks, all almonds are now pasteurized, but can still be labeled raw.
i only buy pistachios in the shell – slows me down.
more than a handful of nuts makes me feel like i’ve o.d.ed on something.
I will pass this on to Mr. squirrel who I feed cashews to every day! He goes nuts for them,
I remember the early sixties, when I was a young’un, it was common for middle class households to have a bowl of nuts and nutcracker in the living room for entertaining. Getting them open was hard work. Great way to avoid over-consumption.