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.
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.