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

Dear Mark: Nuts and Omega-6s

Nuts have gotten a surprising amount of flack as of late. Many nuts have a fairly high PUFA content, and most of that PUFA is Omega-6, which is the bad one. It’s easily oxidized, highly unstable for cooking, usually rancid on the shelf, and, thanks to government farm subsidies and public hysteria over animal fat, it’s in absolutely everything nowadays. We Primal types generally avoid it for good reason, and that tends to influence how we react to the O6 content of nuts. Last week I received this email from a reader:

Dear Mark,

I’m a little confused. I get the animal fat, the meat, the veggies, and the lowish sugar fruit recommendations, but what about nuts? I love nuts, don’t get me wrong… I’m just a bit paranoid about the Omega 6 content. You recommend nuts in the book. If you (and pretty much all other Primal bloggers) tell us to avoid Omega 6 fats, should we still be eating them?  I’m having trouble reconciling the two bits of advice and there seem to be mixed messages out there. Thanks.

Is there a place for nuts in the Primal Blueprint diet? Let’s take a closer look.

Omega-6 Content Various Nuts (1/4 cup)

Walnuts – 9.5 g

Almonds – 4.36 g

Cashews – 2.6 g

Macadamias – 0.5 g

Brazil nuts – 7.2 g

Hazelnuts – 2.7 g

Pistachio – 4.1 g

Pine nuts – 11.6 g

Pecans – 5.8 g

The basic takeaway is that quite a few nuts are fairly O6-intensive (with several, like macadamia nuts, being extremely low). A diet high in these nuts, then, would presumably skew the vaunted tissue O6-O3 ratio toward pro-inflammatory bodily processes… right? I mean, if you were to eat food fried in high-O6 vegetable oil at some restaurant, that would be pro-inflammatory. If you were to eat cheap Chinese food stir-fried in cheap, high-O6 soybean oil every day for lunch, you’d expect a good amount of oxidized LDL at your next lipid test. And if you were to supplement your diet with a few daily tablespoons of unheated corn oil, there would be markedly negative effects (besides gagging and/or vomiting) on your body. How are nuts any different?

For one, nuts aren’t just “bags of linoleic acid” (as Stephan Guyenet recently pointed out in a comment board I’ve misplaced). Isolating Omega-6 fatty acids and then exposing them to air or heat is bad dietary policy. I don’t care where it is – in your body, in your cupboard, or in the skillet. But nuts are much more than linoleic acid. In fact, a nut is a pretty complete nutritional source. After all, it’s the seed of a tree, a sort of arboreal egg. Contained within is everything that tree needs to start growing from scratch – fats, carbohydrates, even protein, plus natural antioxidants like Vitamin E and plenty of minerals. We have to remember that antioxidants in foods exist, first and foremost, to protect the food from damage. That linoleic acid in the walnut isn’t meant for you to consume (we’ve adapted to it, not the other way around); it’s there to provide energy for the budding tree. A damaged, oxidized fat is no good to any tree, and Vitamin E helps prevent oxidation. When we strip a nut of everything but the liquid fat, we’re asking for trouble, but if we eat the whole nut, the fat remains protected by the natural antioxidants, at least to a point (eating burnt, damaged, or rancid nuts isn’t the same as eating raw or soaked nuts). In other words, extracting, refining, and isolating a highly unstable Omega-6 fatty acid in oil form is entirely different than eating the odd handful of pistachios every other day or so. If you roast your nuts to the point of burning, then, yeah, you’re probably eating damaged fats, and that could be a problem. But eating a quarter cup of nuts every few days isn’t going to hurt you – even if they’re high-O6 walnuts (the horror!).

Even if the Omega-6 fat in nuts is bad, the positives of the nut seem to weigh more heavily. Whole nut intake seems to reduce markers of systemic inflammation, and inflammation is linked with a wide range of ailments and afflictions (obesity, insulin resistance, heart disease, excess cortisol, etc.). The study’s (PDF) authors hesitate to isolate and praise a single component of the nut, referring to them as “complex food matrices containing diverse nutrients and other chemical constituents.” I think that’s an accurate appraisal of the humble, irreducible nut.

What’s the Downside?

Problems arise with steady year-round access to foods whose historical availability was seasonal and intermittent. If you were a hunter-gatherer, you probably weren’t gathering bushels of nuts on a daily basis – at least, you weren’t finding enough nuts in the wild to eat eight ounces a day. Nuts should never comprise the bulk of your diet, anyway. A quarter cup as a snack every now and then isn’t going to kill you. It’s not even going to compromise your progress. I mean, they’re nuts. They aren’t meals, and they’re not meant to be. They’re snacks, basic supplements to an already nutritious diet replete in animal fat, protein, and vegetables. And in a high Omega-3 diet like the Primal Blueprint they definitely have a place.

Just make sure you treat your nuts as delicious snacks, rather than staple cornerstones of a meal. Don’t burn your nuts, and don’t cook with the oil. The safest bet is to buy them raw and soak or roast them yourself. That way, you control the heat and you can mediate the oxidation.

Overanalyzing your food intake is a good way to stress yourself out and make every little dietary choice an internal struggle. Avoid falling into this trap. Be vigilant of your food choices, but pick your battles wisely. Making sure you ask the waiter to cook your omelet in butter rather than vegetable oil is worth the trouble; stressing over the Omega-6 content of the twenty walnuts in front of you is decidedly not.

This is a fairly contentious topic in the community, with a ton of bloggers weighing in. Richard Nikoley (last I heard) opts for the harvest-and-gorge nut consumption style, going regular periods of time where he eats none at all. He’ll avoid buying any “for 2-3 store visits in a row.” Remember, Grok didn’t have around the clock access to nuts.

Stephan Guyenet and Don Matesz go back and forth in the comments section of Don’s recent post on walnuts, in which Don offers very sound evidence in favor of walnut consumption. Definitely check it out.

My general take, as I see it, is that nuts shouldn’t make up the bulk of your caloric intake. It’s not that Omega-6s are inherently dangerous, especially bound up in whole food, nut form; nuts may even be beneficial to heart health, probably by decreasing systemic inflammation. It’s that they’re often too available, too plentiful, and way too easy to consume in excess. What drew our ancestors to nuts – the caloric density and the fat content – is what makes them “dangerous” to modern man. Most seeds, including grains, were passed over because the labor involved in their gathering and their refining was prohibitive with inadequate payoff. Nuts are meaty, though, and they’re dense and (somewhat) filling. It makes sense that we easily snack on them all day, because our ancestors probably gorged themselves on nuts when they were available. We should eat them, too, but it’s important to stick to reasonable, evolutionarily realistic amounts.

Care to weigh in with your thoughts on nuts? I know a lot of forum members have reservations about them, so I’d love to hear in the comments section.

You want comments? We got comments:

Imagine you’re George Clooney. Take a moment to admire your grooming and wit. Okay, now imagine someone walks up to you and asks, “What’s your name?” You say, “I’m George Clooney.” Or maybe you say, “I’m the Clooninator!” You don’t say “I’m George of George Clooney Sells Movies Blog” and you certainly don’t say, “I’m Clooney Weight Loss Plan”. So while spam is technically meat, it ain’t anywhere near Primal. Please nickname yourself something your friends would call you.

  1. We have a pretty well stocked pantry at work, I pushed for Raw almonds and they seem to have caught on. In the pic below I tried to encourage people with their choice… later on in the day my addendum was missing, conspiracy???

    Chris G wrote on March 16th, 2010
  2. My understanding is that the ratio of O6 to O3 in walnuts is low relative to other nuts. Macadamias are the only ones close to it.

    The ratio is important yes?

    Almonds have negligible O3. Ratio-wise, they’re at the bottom of the nut list.

    ksan wrote on March 16th, 2010
  3. So, a meal like Son of Grok’s primal pizza should be eaten very rarely, yes?

    Fernando wrote on March 16th, 2010
  4. I eat raw almonds all the time as a snack. I love the taste and consider them a quick and satisfying snack. I buy the small individually wrapped bags at Trader Joe’s so I don’t overdo it.

    Best – Mike

    Fitness Contrarian wrote on March 16th, 2010
  5. Thanks for the mention, Mark. And you’re right on. This is exactly how I handle nuts, going 2-3 weeks at a stretch without any so that when I do get them chowing down with even a whole cup or more in an evening is no big.

    Also, I’m pretty much sticking to macadamias and pistachios from time to time.

    Richard Nikoley wrote on March 16th, 2010
  6. I have recently re-introduced more omega 6 into my diet after avoiding it like the plague and being an omega 3 junkie for many months. Believe me, you do not want too little omega 6 in your diet and there is some omega 6 that is downright beneficial, not to mention essential for inflammation, regeneration and the nervous system. Omega 3 (both EPA, DHA AND ALA) regulate the body’s conversion of omega 6 fatty acids into the pro-inflammatory prostaglandins and leukotrienes and so where there is omega 3, there can also be omega 6. One omega 6 fatty acid that we tend to ignore is GLA which can be found in evening primrose, borage oil and my new favorite seed, hemp. GLA also regulates inflammation and so adding a source of GLA along with your nuts and seeds or in the case of hemp in the same package is a downright smart move.

    In the absence of any omega 6 from sources other than the little bits in meat, flax, chia, olive oil and avocado, an oz or two of nuts and most definitely some hemp seeds is a downright healthy choice. Just don’t go overboard and don’t roast them.

    Stabby wrote on March 16th, 2010
  7. The consensus seems to be nuts are OK, but in moderation… If the main issue here is n6, what is wrong with eating more than a “moderate” amount of macadamia nuts (only .5 g in 1/4 cup)? Also, since they are so low in PUFA would roasted be OK?

    sandra wrote on March 16th, 2010
  8. My only way to regulate my nut consumption (they are SO delicious!!) is to buy them in the shell. Yes it is a royal pain in the ass to de-shell each nut, but Grok had to, right? I just buy a mixed bag… Tip: to max out on the primal factor, dont use a nutcracker either!! Grok on!

    Julie Aguiar wrote on March 16th, 2010
  9. I am big fan of walnuts.

    Multi Wing wrote on March 16th, 2010
  10. For those who have trouble controlling their nut intake, they are now conveniently sold in 100 calorie packets. However, I find it much less expensive to buy them in bulk and exhibit some self-control!

    Melinda Neely wrote on March 17th, 2010
    • That is a useful tip – although as you say bulk is cheaper, so I too take that option. Nuts are moreish and calorie dense so self control is the key…

      Luke M-Davies wrote on March 18th, 2010
  11. I have been eating far too many nuts as of later and have not been feeling well for quite some time. I will cut them out and see if it helps.
    I only recently converted from a vegetarian so eating meat is still a teething process so I was relying heavily on nuts for protein and fat. Its not unusual for me to eat 3 cups a day. Yikes!
    Also I am eating a full avocado every day – can someone tell me if this is also pushing my omega 6 – 3 ratio too far?

    avey wrote on March 17th, 2010
  12. Great article! Everything in context, and everything in the proper amounts.

    By the way, “The Irreducible Nut” would make a great name for a rock-n-roll band. :)

    DianeC wrote on March 17th, 2010
  13. Hi Mark,

    I just wanted to comment on your statement that “Overanalyzing your food intake is a good way to stress yourself out and make every little dietary choice an internal struggle.”

    Especially for folks who may have or are currently exhibiting patterns of disordered eating, getting too analytical with your food choices can cause an unhealthy obsession with the quality of the food you eat, to the point of having a serious impact on quality of life.

    The approach you promote seems pretty balanced, though — there’s a lot to be said for ‘don’t sweat the small stuff’.


    Jesse Bastide wrote on March 18th, 2010
  14. Ignore this…I wanna see if I setup my gravatar correctly. :)

    Mike wrote on March 20th, 2010
  15. The argument that Grok didn’t eat nuts each day doesn’t really work here I think. Cant see that Grok consumed about 3-5 eggs a day either but I got the impression PB says that is okay?

    Rilla wrote on March 21st, 2010
  16. The Primal Blueprint book states (p125): “Nuts and seeds and their derivative butter products are filling and nutritious and can be *consumed liberally* in place of high-carbohydrate snacks.” This seems to be in contradiction with this blog post. Or am I missing something?

    chris wrote on March 31st, 2010
  17. Doesn’t the ratio of O6:O3 come into play with the nuts? Can I assume that’s why the amount of O3 in the above nuts is not listed?

    Diabetic, and so very confused about nuts :(

    Debbie wrote on April 17th, 2010
  18. Wow. This is interesting, because since I added more Almonds, I lost weight. I was for the first four days of eating them everyday, loosing 1lb a day. When I cut back I gained weight. I just had a baby three months ago, and lost all the weight I gained. I never thought I’d be fitting into my pre-pregnancy clothes so fast, compared to my other two pregnancies, I never got back to pre-pregnancy with either of those. I still have the boys weight to loose, but with my little girl, it all fell off. And I was eating Almonds everyday, several times a day, feeling great and less hungry. They were baked into foods, so it was more like Almond flour I ate allot of. I guess I’m just different? Or maybe nursing a little one really changes things? I don’t eat them as often right now (and not seeing weight loss, more like fluxes), even though I and have added Coconut oil into my diet. I add it to my smoothies in the morning, and it’s so good. I love Coconut oil, and can’t say enough good things about it. I also make other dessert foods with all types of coconut, like raw sugarless fudge. It’s really good, and uses Macadamia nut butter instead of almonds. Or Mark’s recipe: Truffles. Thanks for all the info.

    Esther wrote on January 9th, 2011
  19. I try to keep PUFAs under 10%, though I usually only reach under 15%, but given all the research on proinflammatory eicosanoids (obviously derived from n6), I’d say it’s not too bad. I get most of my fats from salad oils (usually 75% red palm oil and 25% olive oil). I’m a big nut for saturated fat, anyone read the 1992 Framingham study where the director pretty much summed it up as “the more saturated fat and dietary cholesterol individuals ate the less they weighed and the lower cholesterol they had?” I’m not aiming for the latter as high cholesterol is pretty healthy, though the former shows great potential for obese people.

    Jay wrote on February 1st, 2011

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