Dear Mark: Omega-6 Deficiency and Saw Palmetto

For today’s edition of Dear Mark, I’m answering two questions from readers. First, is it possible to become deficient in omega-6 fats as an adult? What would that even look like, and is there anything that might make omega-6 more important?

Second is a question related to last week’s feature on prostate health. Is saw palmetto an effective supplement for prostate issues? It depends on the issue.

Let’s go:

I have a question for “Dear Mark”
Here it is:

I am completely and totally primal for 10 years now. Can I become O6 deficient ? Since 90% of my fat intake is saturated or O3.

It’s technically possible to become deficient in omega-6 fatty acids. The early rat studies that discovered the essentiality of Omega-6s found that their complete removal made the subjects consume more food (without gaining weight), drink more water (without peeing more than rats on a normal diet), develop scaly skin, lose fur, urinate blood, go infertile, grow weird tails, and die early. All this despite eating an otherwise nutrient-dense diet with all the fat-soluble vitamins (they even removed the fat from cod liver oil and gave the vitamins), B vitamins, and other nutrients a rat could ever want. The only thing missing was a source of omega-6 fats.

Once they discovered the issue—a lack of omega-6—how’d they fix it?

Coconut oil didn’t work, for obvious reasons. It’s almost pure saturated fat.

Butter worked, but you had to use a lot. The omega-6 fraction of butter is quite low.

Cod liver oil worked, but it didn’t fully cure the deficiency disease.

Lard worked well, as did corn oil, liver, flax oil, and olive oil. All of those fat sources fully resolved the issue and eliminated the symptoms. They were all good to decent sources of omega-6 fatty acids.

They also tried pure linoleic acid (the shorter-chained omega-6 PUFA found in nuts and seeds and the animals that eat them) and arachidonic acid (the long-chain omega-6 PUFA found in animal foods). Both worked, but AA worked best.

Throughout all these trials, exactly how much omega-6 fat did the rats require in their diets to cure deficiency symptoms?

When they used lard to cure it, the rats got 0.4% of calories from omega-6 PUFA. If the numbers hold true for humans, and you’re eating 2500 calories a day, that’s just 10 calories of omega-6, or about a gram and a half of pure arachidonic acid to avoid deficiency.

When they used liver to cure it, the rats got 0.1% of calories from omega-6 PUFA. If the numbers hold true for humans, and you’re eating 2500 calories a day, that’s just 2.5 calories of omega-6, or about a third of a gram of arachidonic acid to avoid deficiency.

The truth is that omega-6 deficiency is extremely hard to produce, even when you’re trying your hardest. Way back in the 1930s, the early omega-6 researchers tried to induce deficiency in an adult by giving him a 2 grams fat/day diet for months. Nearly all fat was removed, particularly the omega-6 fats, and the rest of the diet was fat-free milk, fat-free cottage cheese, orange juice, potato starch, sugar, and a vitamin/mineral supplement. Maybe not the ideal Primal diet, but better than some.

He ended up improving his health, not hurting it. There was no sign of deficiency.

Omega-6 fats are everywhere in the food environment, even if you’re actively avoiding concentrated sources of them. No one is developing a deficiency these days. However, certain conditions might increase the tolerable or beneficial upper limits of omega-6 intake.

If you’re strength training with the intent to gain lean mass, a little extra arachidonic acid can improve your results. The dose used was 1.5 grams per day. Average intake through food runs about 250-500 mg, though Primal eaters heavy on the animal foods are probably eating more.

If you’re recovering from injury or healing a wound, a little extra arachidonic acid can speed it up. AA is an important co-factor in the inflammatory response necessary for tissue healing.

Well done, Mark. My doc just prescribed saw palmetto to reduce multiple nighttime visits to the bathroom, though the research I’m looking at says there’s no clinical evidence to support saw palmetto for prostate problems. Your take?

It depends on the problem.

Large observational trials have found no connection between saw palmetto supplementation and prostate cancer risk. It neither helps nor harms.

Saw palmetto does seem to help benign prostatic hyperplasia, a non-cancerous growth of the prostate. This won’t cause serious health issues directly, but it can impede the flow of urine and lead to multiple nighttime bathroom visits. Saw palmetto is quite effective at reducing nighttime urination. If that’s what your doc is trying to help, I’d say give it a shot.

You might ask about combining saw palmetto with astaxanthin. It’s been shown to reduce the conversion of testosterone into estradiol that can sometimes result from plain old saw palmetto supplementation.

That’s it for today, folks. Take care and be well. Chime in down below if you have any questions or comments.


Mitchell CJ, D’souza RF, Figueiredo VC, et al. Effect of dietary arachidonic acid supplementation on acute muscle adaptive responses to resistance exercise in trained men: a randomized controlled trial. J Appl Physiol. 2018;124(4):1080-1091.

Oh SY, Lee SJ, Jung YH, Lee HJ, Han HJ. Arachidonic acid promotes skin wound healing through induction of human MSC migration by MT3-MMP-mediated fibronectin degradation. Cell Death Dis. 2015;6:e1750.

Bonnar-pizzorno RM, Littman AJ, Kestin M, White E. Saw palmetto supplement use and prostate cancer risk. Nutr Cancer. 2006;55(1):21-7.

Saidi S, Stavridis S, Stankov O, Dohcev S, Panov S. Effects of Serenoa repens Alcohol Extract on Benign Prostate Hyperplasia. Pril (Makedon Akad Nauk Umet Odd Med Nauki). 2017;38(2):123-129.

Vela-navarrete R, Alcaraz A, Rodríguez-antolín A, et al. Efficacy and safety of a hexanic extract of Serenoa repens (Permixon ) for the treatment of lower urinary tract symptoms associated with benign prostatic hyperplasia (LUTS/BPH): systematic review and meta-analysis of randomised controlled trials and observational studies. BJU Int. 2018;

Angwafor F, Anderson ML. An open label, dose response study to determine the effect of a dietary supplement on dihydrotestosterone, testosterone and estradiol levels in healthy males. J Int Soc Sports Nutr. 2008;5:12.

About the Author

Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.

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11 thoughts on “Dear Mark: Omega-6 Deficiency and Saw Palmetto”

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  1. There are a lot of claims out there that saw palmetto causes impotence and ED. I have no independent knowledge of the claims but it’s worth being aware of. Do your own research before taking that supplement.

    1. I believe the mechanism for this is that it is a natural form of Finasteride, for which see Post Finasteride Syndrome. Not something with a good risk/reward ratio it seems. Cialis apparently solves a similar problem without the risk, and it has potentially other benefits.

  2. For any man that wants to support their inner alpha, stay away from these compounds (saw palmetto with astaxanthin) at all cost… they’re both potent DHT inhibitors. Dihydrotestosterone (DHT) has much higher androgenic activity than that of testosterone. DHT is known for its mood, energy, fat-buring, masculine characteristics and confidence-boosting effects in men.

    When it comes to prostate issues, estrogen dominance is more likely to blame. Yes, I’m a man, but you’d be surprised what I’ve learned about estrogen due to how it impacted my own life. I don’t want to clog the posts today but if you’re interested, I’m happy to share.

    1. Hi Liver King,

      Please share your experience with high estrogen in men.

      I always test high and am developing prostate problems ( touching 62 now)

      Thank smuch

        Yes, I’m a man, but you’d be surprised what I’ve learned about estrogen due to how it impacted my own life. Endocrine-disrupting chemicals that favor estrogen dominance in the body are pervasive in our modern world. They have far-reaching health effects warranting concerns for both men and women. When I have this conversation with people, I always go back to the root-cause narrative.

        You can’t out-supplement these chemicals. To be healthy, and to stay healthy, we need a total systems approach with diet, lifestyle, and behavior. This is because our hormones operate on mostly negative feedback loops, whereby higher levels of a given hormone down-regulate production to maintain balance. Similarly, greater exposure to hormones will down-regulate the activity of receptors they bind to, so there is less hormonal signaling being seen by the body.

        Hence why we need a total systems approach. Balancing estrogen naturally should be a major focus for both men and women, especially considering that almost everyone is bathing in phytoestrogens and xenoestrogens in the modern world. I know I was — ten years ago. I developed a lump in my chest, it grew, it got huge… my estrogen was way higher than it should have been, I had estrogen dominance — as do many other men and women in the modern world.

        I eliminated all phytoestrogens and xenoestrogens from my life, which is one reason why I talk about not eating nor drinking nor wearing from non-native materials, because this is yet another source of estrogen. I also provided my body with all the things it needs for detoxification, which includes heavily supporting liver and kidney health. Turns out, I am homozygous for the COMT gene, meaning that I have an 80% decreased capacity to clear estrogen (thanks mom, thanks dad!). So, I further supported my methylation metabolism with lots and lots of liver, egg yolks and a little creatine. My estradiol (e2) went from >80 pg/mL to within 22–26 pg/mL, the lump totally went away (100%), and my life is way, way, way better now as a result.

        SIDE NOTE: Did you know that a good 40% – 50% of methylation resources are used to synthesize creatine… If we give our bodies the creatine that it needs, our methylation cycle improves. I dose with just 2 grams / day.

        Once again, think root cause… and yes, this is only one of them! In biological systems, it’s rarely one (or) the other that produces results (for good or bad), but rather the combination of diet, lifestyle, and behavior. I believe in the Primal Blueprint… I believe in Ancestral Living. Everything I know, breathe and live is detailed on our “About Us” page. I hope that you’ll give it a look and let me know if you have any questions.

        If you email me directly, I do everything I can to help!

    2. Dihydrotestosterone is vital for young lads as it plays an important role in the development of male characteristics during adolescence.

      In men over the age of 40, however, having too much dihydrotestosterone spells trouble, especially for prostate health. It’s just not the kind of testosterone you want to have too much of, unless you are a teenage boy.

      While I agree that saw palmetto extracts might not be the best choice, I would suggest that every 40+ man having problems with their prostate or issues with too much dihydrotestosterone or too much estradiol look into supplementing diindolylmethane (DIM). It lowers serum estradiol, increases total testosterone, and improves your Free Androgen Index. Absolutely excellent stuff.

  3. My intuition is saw palmetto should be part of a synergistic formula and probably something you cycle on and off of, while making sure to do all the primal stuff, get plenty of fats, lift heavy a couple times a week, do HIIT once a week, control stress, good sleep etc. And … there are some studies that indicate increasing testosterone IMPROVES prostate condition (BPH and prostate cancer), contrary to “conventional wisdom”.

  4. Thank you, Mark. The nighttime visits are already down since startin the saw palmetto, and I’ve slept through the night a couple times in the last week – a very rare occurance.

    Lover King suggested bovine prostate supplement last week. Looking into that. And I’ll research all the other suggestions here.

    Grateful for all the beta, gentleman.

  5. Even the trail blazer himself, Ray Peat, has stated an EFA deficiency in the natural order of things is impossible. Only a custom built lab diet could induce a EFA deficiency. Don’t worry about it bro, in fact the lower you get the better your metabolic system will be. A high functioning metabolism means low/no chronic inflammation and extended lifespan. I’ve ate a super low PUFA diet for years, averaging about 3 grams a day, sometimes upwards of 5 grams. I eat NONE of the typical sources of polyunsaturated fat either. My fat sources are strictly from things like coconut oil, grassfed butter, oxtail soup, lamb shanks, grassfed beef liver, skimmed bone broth (chicken usually), skimmed milk, 1% milk, colby cheese, oysters, and wild caught cod. If I’m eating that rare and elusive restaurant meal, which is always drenched in PUFA, I’ll take about 100 units of vitamin E and two low dose (81mgs) aspirins before eating it. This protects against the oxidation and liberation of free fatty acids, thus negating the stress responses.

      1. Ordinarily no, I use to eat macadamia nuts occasionally, however due to their expense I decided to stop. My vitamin D3 supplement is made out of gelatin capsules and extra virgin olive oil. That’s my only daily source of olive oil, however much that is (presumably only residual amounts). Having said this, I wouldn’t go far out of my way to avoid olive oil. When I eat a restaurant meal, I know I’m probably getting food cooked in oils much much worse than olive oil. Just as long as I have my antioxidant (vitamin E) and my anti-inflammatory (aspirin) with the meal I know I’m probably okay provided I don’t make a habit out of eating out.