Marks Daily Apple
Serving up health and fitness insights (daily, of course) with a side of irreverence.
5 May

Dear Mark: Nuts

AcornsDear Mark,

Can you give me more explanation about nuts and seeds? I eat a ton of them and am always confused about which ones are actually nuts and which are seeds and which are legumes. Does it make any difference if you eat them whole, roasted, raw or as nut butter?

Thanks to reader Charlotte for these questions in response to last week’s “Get Primal” post. The classification question does get tricky.

Cashew Fruit

Nuts themselves are actually a kind of fruit, specifically “dried fruit.” But not everything we consider nuts are really nuts. Some are actually seeds, often within fruits or even legumes. A hazelnut is, indeed, a nut. An acorn is also a variety of “true” nut, as are pecans, walnuts and chestnuts. But an almond, for example, is a seed inside a fleshy fruit’s (a.k.a. drupe’s) pit. A pistachio is a seed within a fleshy fruit. Pine nuts are seeds. Cashews are seeds. Peanuts are the seeds of a legume. Technically speaking, all nuts are fruits, and a “true” nut is indehiscent (they don’t – by themselves – open to spread seeds), hard-shelled and generally one-seeded.

But let’s look at all this from a practical perspective: what’s good to eat? “Nuts” in the broad culinary classification contain protein. Big plus. They tend to be high in certain B-vitamins, vitamin E, and many minerals. Another plus. Low carb. Yet another plus. But not all “nuts” are created equal. Some, like peanuts, have high levels of omega-6. As we’ve said a lot lately, we moderns seem to get way more than enough of omega-6 in our diets. Walnuts, for example, offer a nice dose of omega-3. Almonds are a great source of phytochemicals, contain calcium, and are even lower in carbs than most.


And then there’s the issue of aflatoxins, dangerous metabolites produced by certain mold varieties. Aflatoxins are common in what we usually refer to as “tree” and “ground” nuts, including almonds, walnuts and pecans as well as peanuts and cashews. The toxin has been shown to have carcinogenic, mutagenic and immunosuppressive properties. While certain farming practices can reduce the problem, the aflatoxin related molds are considered at least somewhat inevitable. Peanuts are often said to have the highest concentration of aflatoxins, and they are among the most heavily (pesticide) sprayed food grown.

Nut Butter

In terms of roasted versus raw, I’d recommend raw to avoid the oxidation that happens during heating. However, there are increasing challenges to the sale of truly raw (untreated) nuts. The Cornucopia Institute offers a great deal of information on the recent raw almond controversy, but all California grown almonds now have either chemical or high heat treatments. The change came after raw almonds were believed to be connected with two salmonella cases, although farming practices vary considerably and may have contributed to the problem. Regarding nut butter versus nuts themselves, it’s your choice. However, be sure to select nut butter (I recommend almond butter) without added ingredients, especially added sugars. And, again, I’d favor raw and organic over conventional and roasted.

Thanks for the questions, everyone!

steffenz, Marcio Cabral de Moura, sproutgrrl Flickr Photos (CC)

Further Reading:

Dear Mark: Beans/Legumes

Smart Fuel: Walnut Oil

Modern Forager: Ten Staples of a Well-Stocked Kitchen

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You want comments? We got comments:

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  1. I love nuts and eat them everyday, except peanuts.

    Crystal wrote on May 5th, 2008
  2. I would just add that some (myself included) have difficulty digesting nuts of all types and I personally have discontinued eating them for the most part….

    They “stuff” my system, cause constipation and also inflammation! Definitely not good…

    sarena wrote on May 5th, 2008
    • Have you tried crispy nuts? I found the directions in Nourishing Traditions. Soak raw nuts in filtered water with sea salt for about 8 hours. Drain off water and put them in dehydrator around 150 degrees. I used my oven before and put it on lowest temp which was 170 and held door ajar with a wooden spoon to lower the temperature. Nuts are easier to chew, nice and crispy, and they digest better than raw. I believe it is something like soaking grains to make them sprout which makes grains easier to digest also.

      Kat wrote on June 24th, 2014
  3. Thanks for the answer guys!! I swear I should start paying you for all of the awesome advice you have given me:)

    I eat so many nuts, I’m practically a squirrel;)

    charlotte wrote on May 5th, 2008
  4. Serena,

    Some people choose to soak them (as they would beans) to aid in digestion. Because of the mold issue, I’d keep them in the fridge though and thoroughly dry them first with towels and then spread out on a cookie sheet.

    Jen wrote on May 5th, 2008
  5. When I first discovered almond butter a few years ago, I thought the gods had personally handed me a gift. I never knew it existed before that. Okay, it would have been a gift if it had come with a lower pricetag!

    And while I can handle most foods in moderation, dark chocolate covered almonds might as well be crack. I can’t have them in the house, or they vanish very very quickly.

    My 4 yo son loves his cashew butter, and my husband sticks with peanut butter mostly, so we’ve got a jar for each of us. YUM!

    Judy wrote on May 5th, 2008
    • Thanks for the information that nuts cause constipation. Were they any nuts in particular or do I need to see which ones will give me relief from IBSD? For the most part eating PB has lessened my symptoms; still I can’t enjoy the taste of my favorite vegetables and for the most part all of my favorite vegetables are off limits to anyone with IBSD. So if you would be so kind to let me know which nuts can cause constipation I would be most grateful, Aden

      Aden wrote on January 1st, 2016
  6. Mark-

    Good stuff, thanks so much! My husband and I are thinking about training for our next marathon, and we have been reading a lot about how certain nuts are extremely beneficial for runners because of the need for additional protein. This post contains a lot of good info on what we needed to know about.

    Jessica wrote on May 5th, 2008
  7. What’s the scoop on cashews? Good? Bad? OK in moderation but almonds and walnuts are better?


    brassica oleracea wrote on May 5th, 2008
  8. Jen, yeah even the soaking trick doesnt help me at all!!
    And here is a “nut” chart:

    sarena wrote on May 5th, 2008
    being a legume, they contain, in common with all beans, lectins, which attack the intestinal mucus membrane and, in many people, can cause “leaky gut syndrome” – and thus potentially allow whole proteins into the blood stream and may trigger an auto immune response.


    all the best


    markus wrote on May 6th, 2008
  10. I’m with you Crystal, i also eat nuts everyday and love’m! I go to a fresh market and always ask them to grind up “Fresh” Almond Butter before my eyes, can’t beat it!!!

    Donna wrote on May 6th, 2008
  11. My personal story…I used to put almond butter on everything…especially chicken. Tasted so good. But then there came a time where I stopped….and I noticed something. I felt better….especially when dealing with some small sports related inflammation issues. That and I did more research into the unstable enviroment of most PUFAs (Poly unsat fats) and decided to switch up my fat sources. Now I eat mostly Sat and MUFA (with some Omega 3s from fish oil..and there is still plenty of Omega 6s from meats). I rarely eat nuts….but I still enjoy them time to time….but taking them out of my diet (well I was eating a ton of butter) completely made me feel 100x better.

    Mike OD - Fitness Spotlight wrote on May 6th, 2008
  12. I started my career working as an engineer in peanut butter product development (P&G, 1959). There wasn’t much said about aflatoxin then, but in the 60’s the lab was testing for it to be sure it wasn’t in their peanuts. However, I got uneasy about other companies who might not test for it especially when I learned it was thought that the aflatoxin mold groth was aided by darkness and moisture on the bags that the peanuts were often harvested and stored in. Then when I heard aflatoxin is an absolute cause of cancer, I gave up peanuts and peanut butter for good.

    Tom Orlando wrote on May 7th, 2008
  13. (2nd comment) I like almond and cashew butter, alone or mixed. A trick I learned in the peanut butter product developement lab that works for these other nut butters is to add a little (olive) oil and a little lecithin when you make nut butter. The lecithin helps yield a smooth butter. The proportions are not real critical – to a cup of nuts, add 1/8 cup oil and (estimated) 1 tsp of lecithin. I also add a little honey, but that’s extra. Then if you have a Vita-Mix, you’re all set. It makes a great nut butter.

    Tom Orlando wrote on May 7th, 2008
  14. Thanks for the suggestions, Tom! I’ll have to try the lecithin/oil idea.

    Aaron wrote on May 7th, 2008
  15. Many thanks Mark for the email heads-up to this blog post. Just what I was looking for. Wish you all the best mate!

    Ross wrote on December 2nd, 2008
  16. What I don’t get, is that nuts appear to be quite high in Omega 6 fats. And I thought we were supposed to try to balance out Omega 3 & 6s. Here’s a breakdown of some common nuts, per 100g:

    almonds: 49g total fat, 6mg Omega 3, 12065mg Omega 6, omega6:3 ratio: 2000:1
    cashews: 44g, 63mg, 7782mg, 125:1
    pecans: 72g, 986mg, 20630mg, 20:1
    macadamias: 76g, 206mg, 1296mg, 6:1
    walnuts: 65g, 9079mg, 38092mg, 4:1

    So almonds have virtually NO omega 3 fats, buts HEAPS of omega 6 fats! Only macadamias and walnuts seem to have a reasonable ratio.

    By comparison, canola oil has a 2:1 omega6:3 ratio.

    So all this talk of eating lots of nuts, seems, well, NUTS! Can anyone explain this apparent contradiction?

    All data comes from, which gets it from the USDA.

    WildWoila wrote on July 5th, 2009
    • You make a great point, I was wondering the same thing.

      Franklin wrote on February 3rd, 2011
  17. yes i agree – paleo man would have only had seasonal access, so we should only go nuts for nuts once a year…


    markus wrote on July 5th, 2009
  18. While I’m at it, here is the data for peanuts: 49g total fat, 3mg Omega 3, 15555mg Omega 6, omega6:3 ratio: 5185:1.

    So almonds are not really all that different to peanuts, in terms of omega 6.

    WildWoila wrote on July 5th, 2009
  19. Mark,

    if you eat the nuts raw – won’t the phytic acid, that works like a nutrience-blocker, hinder things?

    Or do you soak them and gently dry them – making them essentially still raw, but without the phytic acid that exist in the outer layer?

    Kari wrote on October 27th, 2009
  20. what’s the opinion on macadamia nuts, Mark and everyone? they’re my (and Dr. Atkins’) favorite….

    tess wrote on February 16th, 2010
    • @tess, they’re my favorite, too. For good reason. I have a handful nearly every day.

      Mark Sisson wrote on February 16th, 2010
  21. When I started eating primal sure i lost weight but not until I eliminated nuts from my diet.
    For some reason all nuts make me gain weight just like grains do.
    I ditched the nuts and added raw goat’s milk instead (as my treat) and lost another 7 lbs. from 152 down to 145 lbs.

    suvetar wrote on June 26th, 2010
  22. I like soaking my raw almonds along some stevia or salt, makes a delicious snack.

    Jeff wrote on November 12th, 2010
  23. I’m new to primal eating. It seems that nuts are important, but I’m really allergic to them. Any suggestions of how I could get similar nutrients? Thanks!

    Claire wrote on November 15th, 2010
  24. What’s the consensus on cashews? My nuts are mostly walnuts and almonds (raw and slivered… they’re ridiculously delicious!) but since I’m in college and the only thing they have there are roasted cashews (plus whatever I bring from home) I was wondering where they fall in the Primal hierarchy.

    Teresa wrote on February 3rd, 2011
  25. I just started primal a few weeks ago. I’m frustrated because I think I’m eating great but yet again I find another food that I thought was healthy causes cancer or toxin build up. Is it safe to say you can’t avoid all malice from the foods we eat? I’m still eating peanut cause they’re cheap and almonds cause I like them.

    Jessica wrote on April 3rd, 2011
  26. What about fresh ground peanut butter? I know the fresh almond butter, but is the fresh ground peanut butter (the kind you grind up yourself) at least an okay occasional treat?

    Charlie wrote on May 9th, 2011
  27. if i come near peanut butter, my face is going to blow up.
    for real.

    laptops wrote on September 6th, 2011
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    Affiliate Marketing Tips That Work wrote on November 9th, 2011
  29. Mark – HELP! Our daughter has anaphylactic allergies to peanuts and all tree nuts! Can’t keep them in the house. Are there any other snack foods super high in Omega-3 you can recommend? Greatly appreciate it!

    Stacy Kelly wrote on December 31st, 2011
  30. Chia seeds are a plant source that is one of the highest sources of omega 3s. You can sprinkle them on anything. Also, purslane is a weed here in the US, but is a valued potherb and salad herb in other countries and is high in omega 3s. You can mix it with yogurt if you eat dairy for a cold summer salad or mix it in with a tossed greens salad.

    Julie Fenn wrote on January 27th, 2012
  31. I’ve been eating Sun Butter (sunflower seed butter) I’m in love with it I like it way better than Almond Butter

    Enette wrote on February 1st, 2012
  32. I think that nuts are quite healthy, but you shouldn’t forget about phytic acid which inhibits mineral absorption. Walnuts are the best for heart health (rich in omega-3 fatty acids and oleic acid) so if you’re going to eat nuts in larger amounts, get walnuts!

    Morgan wrote on April 1st, 2012
  33. I having the problem of that many do. I love peanuts, pistacios, walnuts, almonds and cashews. When I eat these “nuts” I break out with cold sore like blisters. Pistacios are the worst and produce the mentioned blisters in half an hours time.

    Since going nut free i have yet to have a break out. I do enjoy soy and sunflower seeds. Does anyone else have the same problem?

    WhirrlingMenace wrote on May 16th, 2012

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