Kurt G. Harris MD

PāNu means paleonutrition. The "paleo" here signifies "old" and not necessarily paleolithic. The PāNu approach to nutrition is grounded on clinical medicine and basic sciences disciplined by knowledge of evolutionary biology and paleoanthropology. The best evidence from multiple disciplines supports eating a pastoral (animal-based) diet rather than a grain-based agricultural one, while avoiding what I call the neolithic agents of disease - wheat, excess fructose and excess linoleic acid.

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Saturday
Jan292011

N-3 supplementation recommendations

I started the current series conflicted about how much detail to put into what I see as mostly an essay on nutritional methodism or philosophy. I could have made it shorter with links, but wanted it to be able to stand alone. So I decided to write it long but break it up into parts. So there is some substance there as well. I am trying to lay the groundwork for future posts that are more in-depth and dealing with the NAD -the putative neolithic agents of disease. 

Chris Kresser of the excellent blog Healthy Skeptic has read Part I and decided to throw down the gauntlet on the issue of n-3 supplementation. You can see his full remarks in the comments section of the previous post. I've abstracted his questions in italic and answered in Roman.

Forgot to mention this, but Beth reminded me. In your article you mentioned supplementing with omega-3 when omega-6 is unavoidably high. What constitutes "unavoidable" for you? Because I think you'd agree that dramatically reducing n-6 intake is a much better way to balance the n-3:n-6 ratio than maintaining n-6 intake at current levels and taking 20g/d of fish oil.

......I'd be curious to know where you land this, Kurt. It's a pretty controversial issue in the Paleo world.

The six people who have read everything on the blog and all my comments elsewhere know that I favor reduction of n-6 in the diet as the way to correct the 6:3 ratio and that I am skeptical of supplementation with fish oil. I would never advocate fish oil at the level of 20g/day and even though I have great affection and respect for Robb Wolf and Dr. BG, I do not think using a "fish oil calculator" that recommends tablespoon or multigram quantities is a great idea. 

At the same time, I find it hard to imagine how 1-2 g/day of known-to-be fresh fish oil or n-3s in tinned sardines is metabolically much different than getting a bit more n-3 by buying pastured beef or butter. As I eat both pastured beef and butter and occasional fish, I only take the odd teaspoon or so of Carlson's fish oil now and then, and I probably would not need to do that all.

The "unavoidably high" group I am referring to is your relative who will make zero change in their overall diet but might be willing to take a few fish oil pills along with their BP meds and useless multivitamins and neutraceuticals, etc.

For the serious readers of my blog, I recommend a high GRAF, low TemPO, and even low NRAF diet at steps one two and three to optimize the 6:3 ratio and minimize total PUFA. The point is BOTH the ratio an the total are important, so fix them BOTH.

I can see the logic of higher doses of dietary n-3 on the theory that one might accelerate the displacement of the unwanted n-6 in cell membranes. But although I don't know the pharmacokinetics of this maneuver inside and out, I suspect the cells "see" serum levels of n-3 and n-6, but not necessarily in the ratio we eat it! So my cartoon concept of this is that 15 g /day DHA/EPA may bump the serum or lipoprotein borne level only slightly (homeostasis and all suggests the serum level might be regulated - we do it for other fatty acids), at the same time there is an order of magnitude more overall PUFA (with n-3 more unstable than n-6) at the level of the gut and liver. It seems we might preferentially burn the excess, but perhaps we store it all and it speeds the displacement of N-6 from the cell membranes. I kind of doubt that, though.

I prefer to avoid all this, and to allow n-6 to just wash out, even if it takes 2 years.

This bias is not something I can prove just with literature quotation, as there are no trials I am aware of that compare n-6 reduction over time to correcting the 6:3 ratio at the expense of increasing total PUFA to a level evan further outside the EM2 than it is already. I think the burden of proof is on those recommending supplementation for this reason. The burden of proof must be high when recommending anything we definitely did not evolve with. I have not read everything on this - who has?, but I've read enough to eat this way in my own family.

 So start your high GRAF, low TemPO, low NRAF diet now and hold off on the fish pills. You won't need to calculate anything then, and with time your cell membranes will have a 6:3 ratio that mimics the EM2.

 

For more info, you can read Fish Oil or not? and Fats and Oils.