Are PUFAs really essential and in what amounts? From different sources one can get different numbers ranging from 1% or even less and up to 8% of total caloric intake.
Well yeah they are essential. Inflammation is part of the healing response, and o-6s also make endocannabinoids which serve a wide variety of important bodily functions and can only be made from PUFAs (PUFAs refers to AA, LA, ALA and DHA/EPA)
Of course omega-3 is important too as well all know. The rub is that these fats get stored, so even if, as the article mentions, one didnt eat them for six months, that doesnt meant youve run out. You would probably still have a load in your adipose. In fat, Ive heard it takes over a year for a turnover (probably more like many years).
Despite them both being needed (from what I understand of their diverse roles and metabolism cascades), Id say the article is intuitively correct on a few particular issues: the heart health recommendations of 10% pufa do not match any traditional diet, and they are probably wack, especially given the role of o-6 in inflammation (plus heart disease is on the rise based on their recommendations).
And you do not see any deficiency signs on traditional diets, which on the whole have much less o-6 than modern diets, and more o-3.
I cant really say how much you need per se though. Id guess its probably reasonably low, and roughly equal to what you get in any ol' whole traditional foods diet. Its not easy to measure this in the way recommended intakes are normally measured because because of the fact it is stored.
Also, AA in meat, is the metabolically superior precursor for the cascade, and the endocannibinoid system, in terms of omega-6 (ie your better to get your o-6 from meat than veg, theres less steps, less nutrients used, less energy and its more efficient). AA itself in studies improves endurance excercise (probably because of its easy conversion to endocannibinoids which are used in excercise).
There again, the levels in meat are fairly low, most of the time, so we are probably expected to get some in LA (plant) form as well (certainly not vege oil levels tho!)
It's impossible to induce a EFA deficiency on a whole foods diet, the only known cases have happened on artificial diets high in sucrose and rigid fat restriction, or on total paternal nutrition diets(intravenous). To avoid a deficiency .5% of calories during growth and 1% for pregnant women- source "The Masterjohn".
So having said that, what is optimal? Well we just don't know, the minimum intake is small and considering we evolved near the equatorial belt where fish are generally lower in PUFA and plant foods more abundant I'd say under 4% is good, but that's just a guess.
There is some epidemiological evidence that high omega 3 could be correlated with bleeding and stroke in greenland inuit but their o3 intake is something like 13.7g/3000 cal.
Also iodine, vitamin c, and vitamin e have some protective quality's against lipid oxidation so if they were higher in the diet I'd suppose you could eat a little more.
If you want to confuse things even more just spend some time at Jack's blog, he doesn't give any limits at all just eat as much seafood as you want and roll the bones. I'm not saying he's wrong just that I'm not sure.
From what I understand, almost all sources of fat are mixed--in other words, there are PUFA's, MUFA's and Saturated fats in just about every natural fat, just the ratios vary.
Most Westerners eat about a 12:1 ratio of O6's to O3's, but the ratio should be closer to 1:1. So, if you avoid sources that are PRIMARILY PUFA you will still be getting PUFA's, but in lower, healthier ratios. So you don't have to make an effort to ADD PUFA's to your diet, it's already there.