The Healthy Skeptic Podcast – Episode 2

May 27, 2010 in Food & Nutrition, Myths & Truths, Podcasts | 35 comments

fishoilonhookIn this second podcast episode I cover the basics of essential fatty acids, discuss the importance of reducing intake of omega-6 and increasing intake of omega-3, and compare the relative benefits of fish vs. fish oil as sources of omega-3.

I go through most of the material I’ve written about in my special report on essential fatty acids, fish and fish oil, but there is some additional material in the podcast that isn’t in the written series.

I’ve also answered a few of the most common questions that came up in the comments section, or were emailed to me by readers.

Topics include:

  • Why flax oil isn’t an adequate source of omega-3 fats
  • The importance of reducing omega-6 consumption
  • How much omega-3 is enough to prevent disease and promote health
  • The advantages and disadvantages of fish vs. fish oil as sources of omega-3
  • Criteria for choosing a fish oil
  • Is vitamin A safe in cod liver oil?
  • Is EPA or DHA more important in human health?

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{ 35 comments… read them below or add one }

Hans Keer May 27, 2010 at 11:19 pm

I would recommend you to read the special report Chris Masterjohn (see his blog) wrote on this subject. Like me he thinks we need no more than between 0.5 and 3 grams of the essential fatty acids (omega 3 and omega 6 together) per day. This quantity you can easily get from eating whole foods. Too much of both omega 3 and omega 6 is bad for us. I made a YouTube video about it, you can find it on the CutTheCarb-channel. VBR Hans


Chris Kresser May 28, 2010 at 7:25 am

I read Masterjohn’s report when it first came out.  I agree it’s wise to minimize total PUFA, but there’s an enormous amount of evidence suggesting that fish consumption at the levels I outlined is protective against many diseases.


yarrow May 28, 2010 at 11:02 am

I have enjoyed both of your podcast so far, so great to absorb this information while doing the dishes.  I have a simple question.  Does the canning process damage Omega 3 fatty acids in fish?  I’ve heard that even cooking salmon at a high temperature can damage these oils.  Thanks for all your research.


Chris Kresser May 28, 2010 at 1:33 pm

That’s a good question. I’m not sure about the canning process, but it’s true that cooking salmon at high temps will oxidize (damage) some of the omega-3 fats. As I mentioned in the podcast, omega-3 fats are highly unsaturated, which makes them vulnerable to oxidative damage.


Moises May 28, 2010 at 5:38 pm

Thanks for pointing me to the links on Vitamin A’s relation to Vitamin D. This forced me to review the evidence carefully on both sides.
As the title of your blog suggests, the reasonable approach is to acknowledge that there remains a high degree of uncertainty in this area, and all reasonable people should be willing to keep their minds open to additional data as it arises.
That said, I find Cannell’s argument more compelling than Masterjohn’s. By the way, this does not mean I uncritically endorse all of Cannell’s views. I believe, for example, that his understanding of what constitutes a healthy human diet is inadequate.
So, let’s leave the personalities out of this, since that all participants in this dispute are people of integrity.
The claim that the studies show correlation, not causation, I believe is weak. I can’t disprove it, but the weight of the evidence appears to me to support Cannell.
You are correct in asserting that Cannell seems only to cite epidemiological studies. And, of course, any particular epidemiological study can only demonstrate the existence of a correlation.
But what Cannell does is more subtle; he cites multiple epidemiological studies. Essentially, he patches together different studies in order to create a treatment and a control group. But, instead of having a treatment and control group in a single study, he will use one study for the treatment group and the other study as a control.
Cannell looks at cancers. He finds that in populations where vitamin D is nutritionally available only in combination with vitamin A, high blood levels of vitamin D are associated with high levels of cancer. “Associated” means “is correlated” with. It does not tell us about causation.
In order to determine causation, we need a control group. Cannell finds such groups in populations where vitamin D is not bound with vitamin A. In these populations high blood levels of vitamin D are not associated with high levels of cancer.
Group I gets D and A and cancer. Group II gets D alone and does not get cancer. Cannell has cobbled together an interventional meta-analysis.
Of course, even placebo-controlled interventional studies cannot prove causation. If we are truly sceptics, we must always remain doubtful that all confounding variables have been controlled properly.
However, my review of the evidence leads me to conclude that I will avoid higher concentrations of vitamin A. I have a lot of respect for the people at Green Pastures, and currently use their X-Factor Butter Oil. I have, in the past, taken their cod liver oil. But, until I see more compelling evidence, I will avoid cod liver oil for the foreseeable future.
(You might have addressed some of this in your latest podcast, which I have not listened to.)


Chris Kresser May 28, 2010 at 6:18 pm


I’m glad you’re digging into this stuff!

Holick and Linday were the vitamin D researchers that published the original article on cod liver oil that Cannel commented on, thus starting this whole vitamin A debate. Holick and Linday recently published a rebuttal comment to Cannel in the same journal. I don’t have the full text electronically, but I read it at the medical library.

Masterjohn wrote a commentary on it here. A few tidbits:

- The authors pointed out that in Dr. Linday’s randomized, controlled trials, cod liver oil supplementation cut doctor’s visits for upper respiratory infections between one-third and one-half. Cannell’s paper called this “less than robust,” but most of us would consider such a reduction meaningful, especially if it could mean we could get sick half as often by taking cod liver oil!

- Dr. Linday and her colleagues offer a suggestion: poultry studies suggest optimal A-to-D ratios between four and eight. Similarly, in her own studies showing cod liver oil protects against upper respiratory tract infections, Linday supplied her patients with A-to-D ratios between five and eight.

- They also point out that rat studies showing that vitamin A is toxic and antagonizes the effects of vitamin D used much higher ratios, ranging from 5,000 to 55,000!

The ratio of A to D in Green Pastures FCLO is between 2:1 and 3.5:1, well within Linday & colleagues’ recommendation, and far, far below the ratio that proves toxic in animal studies.


Alan May 30, 2010 at 8:09 pm

I enjoyed your podcast on essential fatty acids. Didn’t have time to read all the posts , but was able to listen to the podcast.
You mentioned that 0. 5 to 1 percent of ALA (alpha-linolenic acid) will get converted to DHA, not a whole lot.  How much LA (linoleic acid) will get converted to AA (arachadonic acid)? I have this feeling that it is much higher than 1 percent. I didn’t realize until now that AA and DHA are the essential fatty acids!!


Chris Kresser May 30, 2010 at 8:50 pm

I didn’t come across any exact stats on the conversion of LA to AA, but it in general it is significantly higher than ALA to EPA/DHA.  There are only three steps to convert LA to AA, whereas there are five steps to convert ALA to DHA.  Also, as I mentioned in the podcast, ALA and LA compete for the conversion enzymes and Westerners eat far more LA than ALA.


Moises June 2, 2010 at 9:07 am

Thanks to some of your links I have looked into this further. I saw Masterjohn’s journal article abstract. I appreciate all the work you have put into this. The more I look at this, the weaker Cannell’s argument appears to be.
Great stuff!


enliteneer June 4, 2010 at 8:35 pm

Studies, or stats of any kind, is pretty hard to find for the conversion efficacy of short chain omega-6 to AA…
But according to this site,
it’s less than 0.1%!    Makes you wonder how there is *ANY* inflammation effect from long-chain omega-6s given that low conversion rate!!


Mart June 4, 2010 at 8:55 pm

I hate fish. It makes me gag. Cannot eat it at all. So I guess I’m out of luck…


Chris Kresser June 4, 2010 at 9:47 pm

Take a high quality fish oil along with a high fat meal each day and you’ll get most of the benefits. Make sure you’re getting enough selenium and vitamin D from other sources.


Chris Kresser June 4, 2010 at 9:53 pm

Yeah, that’s interesting entliteneer.  I guess the eicosanoids produced from AA are extremely potent.


Hans Keer June 4, 2010 at 11:47 pm

To Mart. A very good way to get a lot of omega 3 is by eating salmon or trout fish eggs. You can buy them in the cooled section of the super market. In my point of view a better, cheaper and more tasteful “supplement” than fish oil. VBR Hans.


Mart June 5, 2010 at 12:58 am

Thanks Chris – from your stellar podcast I had by the end of it concluded that this is my best option.
Hans – just the thought of that makes me gag :)
Chris: any thoughts on the quality of Puritan fish oil/omega supplements, and/or on Trader Joe’s Omega supplements?
Off-topic point:
The trouble with switching to a healthy diet like this, with grass-fed this and wild that is that it ends up very expensive, These are presently luxury items, and I can’t afford anything more than regular supermarket prices, I definitely can’t afford Whole Foods organic prices. I wish there was some guerrilla low-budget way to apply these principles.


Hans Keer June 5, 2010 at 6:07 am

My pleasure Mart ;-) .


Chris Kresser June 5, 2010 at 7:37 am

I don’t know that product specifically, but see my Definitive Fish Oil Buyer’s Guide for criteria for choosing a good product.

I know that some of the grass-fed, organic meat can be expensive.  What we do to reduce the cost is buy directly from a farmer.  For example, we just bought a quarter of a cow from a local ranch.  We got 120 pounds of premium, grass-fed beef for about $5.30/lb.  That’s pretty comparable to grocery store prices, when you consider that the cuts we got include New York steak and filet mignon!

If you can’t afford grass-fed, try to at least get hormone and antibiotic free.  I believe TJ’s sells that, no?  You can also focus on buying cheaper cuts like brisket, chuck roast, bones, etc. and learning to prepare them.  Those are actually some of my favorite cuts, so no loss there.  There’s a book I love called The River Cottage Meat Book that will help you with this stuff.


enliteneer June 5, 2010 at 11:57 am

Just in case anyone is interested in the source for the <.1% conversion for n-6, it appears it comes from this study:
Which it of course, has further references:
“The low long-chain conversion of LA reported here is consistent with results from other human studies (18, 39, 56, 57) and with animal data (51, 58, 59) and reflects the low initial conversion of [13C]LA to [13C]DGLA”
Thanks to Joyce Nettleton for the link:


Marek London June 8, 2010 at 8:34 am

I feel that flaxseed oil has been treated a little unfairly, as the ALA it contains can heavily contribute to levels of EPA and DHA (long-chain polyunsaturates) in the body.
Some studies show minimal conversion between ALA and the long-chain omega 3s. Other studies show that men convert 16% of the ALA into long-chain omega 3s while women convert 36%. Other studies show men convert just as well. My experience is that anyone with lipid management problems (high cholesterol etc), chronic disease, nutritional deficiencies or over 50 will struggle with conversion – everyone else is fine.
In any case, I do test my clients for red blood cell fatty acids so I can measure the difference when I use fish oils and flaxseed oil. I often end up using both.
(British Journal of Nutrition 2002 Oct;88(4):355-63 Eicosapentaenoic and docosapentaenoic acids are the principal products of alpha-linolenic acid metabolism in young men*. Burdge GC, Jones AE, Wootton SA)


ben June 9, 2010 at 9:33 am

Regarding  inflammation…   don’t Long Chain omega-3 *AND* omega-6 PUFAs have pro- and anti-inflammatory properties, depending on the conditions?
The simplification that omega-6s are pro-inflammatory and omega-3s anti-inflammatory is just that, a gross oversimplification.


Chris Kresser June 9, 2010 at 9:37 am

I wouldn’t call it a gross oversimplification at all.  Eicosanoids produced from n-6 are significantly more pro-inflammatory than the n-3 metabolites.  Yes, some n-6 eicosanoids are involved in the resolution stage and are thus not inflammatory, but by and large they are much more inflammatory than n-3.


Ted Hutchinson June 9, 2010 at 12:27 pm

Resolution of Adipose Tissue Inflammation
Full text of an interesting paper that readers of this thread may also enjoy.
There are some good illustrations that make  it a bit easier to understand.


Chris Kresser June 9, 2010 at 12:31 pm

Thanks Ted. I read that paper recently and enjoyed it. A good resource, as you suggest.


Tim June 9, 2010 at 2:02 pm

A great analysis of the Vitamin A issue. I don’t believe Cannell either.
What are your recommendations for a (1 month old or so) baby that is not breast fed? Is there some DHA containing product that is specifically for babies? And should one just put some drops fish oil into the baby formula? Thanks.


ben June 9, 2010 at 3:16 pm

The Resolution of Adipose Tissue Inflammation link seems to be broken
( )
Is this article the same as the article for sale here:


Ted Hutchinson June 9, 2010 at 3:44 pm

Sorry I’ll try again with a link to
Resolution of Adipose Tissue Inflammation
and  yes I presume it is the same paper you link to as it has the same authors and title. If this link doesn’t work just google
“Resolution of Adipose Tissue Inflammation”
and you’ll find the link.


Chris Kresser June 10, 2010 at 8:57 am


The two most important nutrients a bottle-fed baby isn’t getting are DHA and probiotics.  I can’t stress the importance of either enough.  DHA is usually given in its algae form to babies because of the potential for seafood allergy.  Probiotics should be put in the bottle.  A good multi-species product focusing on low D-lactate species is good at a dose of 50-100 billion CFU.  Prebiotics, especially GOS and beta-glucans, are also important for infants because they promote the growth of species that can’t be supplemented with probiotics.


chuck p October 19, 2010 at 6:14 pm

Seems whenever there’s too strong of a push in one direction, they’ll be a bounce that will bring it back closer to the middle!
I’ve seen it with glucasime sulfate (not quite the osteoarthritis cure):
fructose (not quite the villain):
vitamin d (not quite the wonder drug): ,
fat and carbs (see movies: super size me vs. fat-head)
and now omega-3s:
I guess its best to do your homework and not to think it terms of absolutes, nor in single nutrients!


chuck p October 20, 2010 at 6:51 am

forgot insulin (fat maker role overblown)


chuck p October 26, 2010 at 7:14 pm

I should have listed as well, since he’s been a long time proponent (err.. opponent ) of omega-3 supplementing!

It might be to early, but the consensus that omega-6 is bad might also change someday!


James G December 21, 2010 at 1:15 am


I appreciate the reasoned and sober analysis of the issues addressed in your blog.

The podcast and articles suggest that omega-3 supplements will be better absorbed by the body when taken along with a high-fat meal. What is an example of a simple, traditional breakfast (that’s when I take my supplement) for a non-vegetarian that is high in the right kinds of fat? Are things like eggs, bacon, or yogurt good, or are they too heavy on omega-6 and trans or saturated fats? Does oatmeal have enough fat?



Chris Kresser December 21, 2010 at 7:33 am

Eggs, bacon, yogurt, kefir, butter, coconut oil/milk, avocado, etc. would all be good choices.


Glenn Atkisson January 18, 2011 at 11:39 pm

Have to agree with Hans Keer’s very first post. Here’s how I see that we have come up with this distortion of logic that has us consuming large quantities of EPA and DHA from fish/krill oil now.

1. Someone measured the amount of omega-6 and omega-3 being consumed now days, say in the US, and then compared that to the intake in primative cultures, or by other animals. I don’t really know. But it was obvious that a 30 or 40 to 1 ratio of omega-6 to omega-3 was a recent and unhealthy distortion.

2. Someone decided that its easier to sell a supplement than to get people to stop eating junk food, so we got the omega-3 pitch, big time. Buy fish oil, don’t worry about how tainted the veggie oil is that you’re eating (adulterated omega-6).

3. Part of the easy way to sell the omega-3 supplements and to interpret the data for what good things omega-3 does is to label omega-6 as “bad”, either because there was too much in the diet, or because the main sources in the diet were adulterated and had become rancid or turned into trans fats by the time they were ingested. Nonetheless, the “too much” and “bad” were not carefully defined, so now the general public interprets this to mean “don’t eat omega-6 at all, definitely don’t take any in a supplement form” but they have no idea how much they are getting because hardly anyone will, in the same sentence say that “commercially ruined vegetable oils are bad, but the human body NEEDS, NEEDS, NEEDS, healthy omega-6 oils the same as ever, and actually more of them than it needs of omega-3′s!” . Nope, we’re on a fever pitch, omega-3 sales binge that won’t stop.

4. To insure that people were getting their omega-3 from a fish supplement rather than a vegetable supplement, research was turned up that seemed to prove that vegetable sources of true, essential Alpha Linolenic Acid were only spottily converted to the important derivatives, EPA and DHA. So now they’re not happy just pushing omega-3, but the fish oil companies have to see if they can shut out the healthy veggie oil companies from their business.

Its really about as bad as the deceptive advertising the drug companies are using, once you know the facts.

If you want a really good discussion on the physiology of essential fatty acids in the human body, go to

Don’t just read one of Brian’s articles. Read every one and listen to the interviews and watch the lectures. By the time you’re finished, you’ll know a lot more about essential fatty acids than you’ll ever get from reading everything else in the popular press.

Most everything else you read has come down from the vendors and is half truth.

For instance, some of the realities are that what has always been described as “essential” is still truly essential. The two essential fatty acids are LA (omega-6) and ALA (omega-3). The derivatives they sell in fish/krill oil are just derivatives that you body can make and has been making for millions of years. The truth is that, no, you body is NOT inefficient at deriving EPA and DHA from ALA (“only a small percent can be converted” is the quote). You body converts what it needs, when it needs it, and INSIDE EACH OF YOUR ten trillion cells. It doesn’t need a lot of DHA and EPA being transported in the blood by overworked cholesterol, only to be dumped somewhere inside cells. There is already a system in place that has always worked just fine at deriving EPA and DHA in the cells when they are needed. Using fish oil to deliver EPH and DHA to cells is a rip off. Think about it. A decade or two of humanity has used fish oil. What did our poor bodies do before the last 20 years?

Another truth is that not only does your body need omega-6 in a healthy form, but the primary cause of both cancer and heart disease is that the adulterated omega-6 fatty acids that we ingest from commercial vegetable oils and trans fats are taking the place of once healthy omega-6 in our cells, yet are not providing the functionality of healthy omega-6. And its going to take as long as it takes a type of cell to regenerate to get a healthy cell with healthy omega-6 in it, once you get off of junk food and start ingesting healthy omega-6. Several months. Brian Peskin spent a long time analyzing the amounts of all the fatty acids in the different types of human tissue. Only in his documents will you learn how much of each type of essential fatty acid is in each type of human tissue. Just as a tease to read his documents though, the wildest ratio is in human skin, where the amount of LA, or parent omega-6, actually outnumbers the amount of ALA, or parent omega-3, by 1000 to 1. So you can see its a little distorted to tell people very simply “Stop eating omega-6″ and it would be way more responsible to present the whole story, lengthy as it is.

Stay healthy, stay skeptical and keep researching.


gogogo5 February 16, 2011 at 10:30 pm

It is precisely posts like the one above from Glenn Atkisson that puts me, your average dude discovering about health and nutrition, into complete disarray.  I have bought into this fish oil supplementation but wonder now if this is wise?

Please could the so called experts pls chime in and comment on Glenn’s post as I’m becoming skeptical about being skeptical!!!


vlado2020 March 3, 2011 at 6:47 pm

Say if omega’s are “essential”, how is their deficiency manifested ?
This article by Ray Peat and a dozen of related links convinced me and taught me of the dangers of omega’s to health.
Why do people expect to get health from stinky fish oils and why are people ostensibly promoting unprocessed food promoting ultra processed fish oils? I guess with good marketing some desperate souls will do anything .


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