The ratio of omega-6 to omega-3 (hereafter, n-6 and n-3) in the diet determines the ratio in tissues. Since these molecules have many cellular roles, it doesn't stretch the imagination that they could have an effect on health. Hunter-gatherer and healthy non-industrial cultures typically have a favorable ratio of n-6 to n-3, 2:1 or less. In the US, the ratio is currently about 17:1 due to modern vegetable oils.
DHA, a long-chain n-3 fatty acid, is concentrated in neuronal synapses (the connections between neurons) and is required for the normal functioning of neurons. n-6 fats compete with n-3 fats for space in cellular membranes (which have a fixed amount of total polyunsaturated fat), so a high intake of n-6 fats, particularly linoleic acid, displaces n-3 fatty acids. Lower tissue levels of DHA and total n-3 correlate with measures of hostility in cocaine addicts. Feeding mice a diet high in linoleic acid increases aggressive behavior, and increses the likelihood of rats to kill mice.
If the ratio of n-6 to n-3 in the diet predicts psychiatric problems, we'd expect to see an association with n-3 intake as well. Let's take a look:
This is homicide mortality vs. n-3 intake for 24 countries, published here. The association is significant (p> 0.001) even without correcting for n-6 intake. Of course, one could see this as a cloud of points with a few well-placed outliers. Here are some closer associations from the same paper:
It's clear that both a high n-6 intake and a low n-3 intake correlate with negative psychiatric outcomes. Together, the data are consistent with the hypothesis that the ratio of n-6 to n-3 impacts brain function. Dr. Hibbeln and Dr. Lands do not claim that this ratio is the sole determinant of psychiatric problems, only that it is a factor.
Now to address the big criticism that was brought up by very astute readers of the last post, namely, that the data were purely correlative. Believe me, I wouldn't even have posted on this topic if I didn't have intervention data to back it up. In addition to the animal data I mentioned above, here are more studies that support a causal role of fatty acid balance in psychiatric problems:
- EPA supplementation (a long-chain n-3 fatty acid) reduced aggression and depression in a group of women with borderline personality disorder.
- DHA supplementation improved aggression in young Thai students.
- n-3 supplementation improved symptoms of bipolar disorder.
- EPA supplementation improved symptoms of unipolar depression.
- n-3 supplementation improved perinatal depression.
- n-3 supplementation improved symptoms of major depression.
- DHA and EPA supplementation reduced suicidal behaviors and improved markers of well-being in patients with recurrent self-harm.
- n-3 supplementation decreased anger and anxiety in substance abusers.
Fish oil capsules for me then!
Wonder how often prisons serve salmon? Probably not often enough!
Hi Stephen, Great info, thanks!
I know and am a big fan of both Dr. Lands and Hibbeln, having followed their work for many years. In case you're not aware of it, here's another chart from one of Dr. H's presentations that helps explain the chronic imbalance of omega-3s and 6s in the western diet: http://www.vitalchoice.com/uploads/Soy Oil Production-Hibbeln.jpg
I also want to call your attention to a free newsletter that you may find of interest here: www.vitalchoices.com. Just search for "omega-6" and you'll find many high quality related articles.
PS: found your blog via a google alert for "omega-3s"
Also of note:
Prisoner violence reduced (pilot only so far)
Improvement in children's behaviour
Pay Now Live Later
Excellent post, as usual. This is especially good for me as I have depression running in my family. I have passed this on to family members for them to read. Great job getting the word out on this. This is one of the only avenues where we get this info as advertisers would rather take Pharma $ for prozac, etc.
Keep up the excellent work.
I'd be curious what your thoughtful eye made of chia seeds? I take a table spoonful every morning.
Very interesting, glad I can chuck out my omega supplements and rather focus on getting the ratio right :)
I've just started reading your blog, and have found all the posts very insightful.
Thanks especially for the wheat and leptin resistance info. The evidence is so clear, why isn't the scientific community (or rather the part that seems to control the "recommended diet") looking into this? I keep telling my family to avoid wheat like the plague, but it doesn't help when wheat is marketed to be so good for you! :(
You have to wonder whether poor nutrition in prison contributes to the problem.
Great chart! I may use that in a future post.
Thanks for the studies. I tried to choose the most compelling ones for my post, but there are others out there.
Thanks. My feeling is that genes determine susceptibility to an unnatural lifestyle, and nearly anyone can be healthy and happy if their lifestyle is good.
I'm OK with chia seeds. Apparently they have a long history of use in the Americas. They have a lot of n-3 and not much n-6, another point in their favor.
However, animal sources of n-3 are the best, particularly fish oil. That's because the big players seem to be DHA and EPA, long-chain fatty acids that your body makes from alpha-linolenic acid (plant n-3). You don't make very much of it though, so eating fish or taking fish oil is a good idea, unless your n-6 intake is very low. Fish oil is naturally rich in DHA and EPA. I'll be going over this in subsequent posts.
I believe the reason many people are blinded to the big causes of the diseases of civilization is confusing epidemiology. The diet/health field has been misled by a number of false epidemiological associations that haven't held up in intervention trials. But people were so convinced by the associations that they refused to accept the intervention results, even though the latter are the only way to determine causality.
I think the tide is turning though. There are papers coming out on interventions with the "paleolithic diet" that I will review soon (the results were excellent), and there are more paleo diet trials in progress. It may take the old guard a while to relax their grip on the field, but hopefully people will understand when the data are staring them in the face.
Any idea on what the n-6 to n-3 is for meat, primarily beef that's grain fed verses grass fed?
So far, I haven't paid much attention to trying to get grass fed beef, I just get beef. I do take three fish oil caps and two cod-liver oil caps per day (5g total) (along with two butter oil caps from Green Pastures).
Beef has very little PUFA to begin with. Grass-fed is about 3:1 n-6 to n-3 I believe, while grain-fed is considerably higher. But since beef fat is only about 4% PUFA, eating a little fish or taking fish oil easily balances your intake. There are other good reasons to eat grass-fed beef though, like CLA for example. It sounds like you're not eating much PUFA in general, so you probably get more n-3 than n-6 because of the fish oil.
Meat that naturally has more PUFA like chicken will have more n-6 if it's grain-fed. Chicken is pretty much always grain-fed. Same goes for eggs. Pork is between beef and chicken in its PUFA content. Leaf lard is the lowest in PUFA of any cut of pork. Naturally raised chicken and pork will have more n-3 but not necessarily a good ratio.
My philosophy is to keep total PUFA intake low and keep the ratio good by eating fish or taking a bit of fish oil.
Interesting data. I hope more people in the psychiatric field become aware of this. Increasing Omega 3s in diet would be way cheaper than SRIs like Prozac and without the harmful side-effects. With the growing problem of overmedication of children, alternatives such as this should definitely be looked into (as well as why more people today need to be medicated in the first place).
Definitely. Check out this post on nutritional alternatives to antidepressants:
I think the biggest value of nutrition is as a preventive measure. It's a lot easier to prevent problems than to fix them.
n-3 LCFA means EFA+DHA right?.
Many populations dont not consume fish but get their omega-3 from linolenic acid.
Has this factor been incorporated in the plots shown?
I have read that high intake of PUFA depresses conversion of mother omega-3 to
EPA+DHA. So how much PUFA we should be consuming if we dont eat fish?
Humans can manufacture DHA and EPA from alpha-linolenic acid but we don't make much of it. It may be sufficient if your n-6 intake is low. As you said, a high n-6 intake inhibits the conversion.
However, I think it's probably best to get at least some DHA and EPA from food. Fish aren't the only source though, land animals contain some as well. DHA and EPA seem to be part of a group of substances we benefit from that are only found in animal products.
Does butter contain appreciable amounts of EPA+DHA?.
I suppose brains would contain some DHA. Sheep brains are popular where I live.
I believe grass-fed butter does. Brain should be a rich source of both. It's almost impossible to get your hands on brain here because of the mad cow/scrapie scare. They just throw it away, even if the animals are grass-fed.
Butter Omega 3:6 content
Omega 6 Linoleic 2.2
Omega 3 Linolenic .3
Grass fed has a better profile. Cattle that graze more freely seem to do even better.
What is the biggest source of Omega 6. Common vegetable oils.
For most cutting down Omega 6 is at least as important as ensuring adequate Omega 3.
Chicken are a significant source of Omega six
100grams chicken + skin has about 3grams Omega 6 and 200mg Omega 3
Conversion of 18 carbon plant based Omega 3 and 6 to longer 20 carbon EPA and 22 carbon DHA is blocked by a long list of factors in the Western diet including High Omega 6 in the diet.
Conversion is also blocked by stress and age.
Author Omega Six The Devils Fat
Your "displaces DHA" link is just sending me to the PubMed home page. Do you still have the original link? Thanks!
Food Is Love
Oops, that happens sometimes. I'll fix it when I get home.
This is the link for the Omega content in chicken.
While I buy the notion that n-3 is mostly good and n-6 mostly bad, I think the "optimal n-6/n-3 ratio" is a red herring. The optimal ratio is probably approximately zero. (I know we need a touch of arachidonic acid, but anyone who eats food can't avoid getting enough.)
I guess you mean we only need low levels of the Omega 6 18 carbon fat derived from plants, maybe 1% of calories or under on the grounds it would have been scarce in the natural diet.
The long chain fat came from the marine environment originally and were a presumed necessary dietary constant, and Professor Crawford in The Driving Force suggests that it was high availability of long chain fats in the shore environment that precipitated human brain expansion.
Robert Andrew Brown
Author Omega Six The Devils Fat
When you say the ratio should be zero, do you mean we shouldn't eat any n-6 fat? Keep in mind that both n-6 and n-3 are essential fatty acids. Besides, you can't avoid n-6 even if you try. There has to be some ratio, the question is which one?
Is there a dark side to n-3's, peroxidation?
"Consistent with these results, rats fed DHA-containing oils had more thiobarbituric reactive substances in these organs than the controls. Thus, high incorporation of (n-3) fatty acids (mainly DHA) into plasma and tissue lipids due to DHA-containing oil ingestion may undesirably affect tissues by enhancing susceptibility of membranes to lipid peroxidation and by disrupting the antioxidant system."
"These results indicate that polyunsaturation of n-3 fatty acids is the most important target for lipid peroxidation. This suggests that the ingestion of large amounts of DHA oil enhances lipid peroxidation in the target membranes where greater amounts of n-3 fatty acids are incorporated, thereby increasing the peroxidizability and possibly accelerating the atherosclerotic process."
"The results obtained in Expts 1 and 2 indicate that DHA enhances the susceptibility of the liver and kidney to lipid peroxidation concomitant with higher levels of DHA in these tissues, as shown by the fatty acid composition. In addition, VE is unable to protect membranes of the liver and kidney rich in DHA from lipid peroxidation, even after ingestion of the highest level of VE."
Any thoughts on what level of n-3 consumption maximizes the benefits while minimizing the peroxidation downside?
The human body is designed to handle a certain amount of oxidation and its peroxide products without ill effect.
I think the best way to answer your question is to look at what healthy non-industrial cultures were eating.
The Inuit had a very high intake of n-3 fats, and probably a moderate n-6 intake. They also ate virtually no carbohydrate, and some have speculated that may be the reason why they could tolerate so much polyunsaturated fat. There were tribes in the Pacific Northwestern US that had a high n-3 intake and also ate more carbohydrate, but I don't have any health data beyond anecdotes (they were said to be very healthy).
The Kitavans eat about 4 grams of fish fat per day. Given their high-carb diet, I would think that 4 g is probably well tolerated by just about anyone. That's just under a teaspoon of fish oil.
Based on the epidemiology in this post, Drs. Hibbeln and Lands state that 3.7 g/day of fish oil would be enough to restore an acceptable 6/3 ratio to the average American (similar to Japanese), despite the high n-6 intake.
Thanks for the links. An interesting and difficult question.
Firstly 9% of energy is a whack of DHA, and far more than would be taken except in trials. 1% of cals is about 2grams a day of DHA about 4tps of fish oil which I imagine would be about the outer limit for most people.
A trial in women suggested uptake of DHA drops off at about 2 grams a day.
My most simple view on this was similar to Stephan's. Populations eating high levels of fish and likely with low omega 6 intake are arguably much healthier than the rest of us. Dolphins do very well on very high fish intake.
In some circumstances long chain Omega 3s have been recorded as anti oxidants. Also DHA processes connect into melatonin production. Melatonin is a powerful antioxidant that protects mitochondria. So does DHA have its own related oxidisation protection mechanisms?
It must depend how the oxidation is being generated as well eg mitochondrial type energy processes, or chemical reaction like eicosanoid production, and where if at all do the two meet. (One I am struggling with if anybody can help)
We need oxidation to provide energy and create weapons systems for cell control immune response etc. So you could flip the question on its head and say how much high quality DHA oxidation do we need to properly control defective cells etc?
My rather hazy conclusion based on a number of factors is that we were designed to oxidise Omega 3 and store omega 6. Omega 6s are second rate fuel.
Excess Omega 6s oxidation appears to cause arterial damage and my unanswered question; is that damaging oxidation the result of eicosanoid omega 6 chemical oxidation cascades rather than mitochondrial oxidation?
Robert Andrew Brown
Omega Six The Devils Fat
"Dolphins do very well on very high fish intake."
First time I've laughed out loud on Stephan's blog.
Let me rephrase my thought. While a tiny amount of the omega-6 arachidonic acid seems to be essential, I've heard of no evidence that the required amount depends on your omega-3 intake. And I've heard of no attempt to quantify how much omega-3 is "too much", never mind whether that amount is proportional to omega-6 intake. Yet people always seem to talk about an "optimal omega-3/omega 6 ratio." What evidence is there that the two are linked?
I can understand, for instance, that there is an ideal zinc-copper ratio because the two minerals compete for the same absorption sites. But why would the ideal intakes of omega-3 and omega-6 be related to each other?
"But why would the ideal intakes of omega-3 and omega-6 be related to each other?"
Because they are linked in may ways including;
1. Sharing the same pathways and conversion enzymes by which the 18 carbon plant fat is elongated to the 20 and 22 carbon fats of the same family.
2. Competing for common enzymes like COX2 fro onward conversion of the 20 carbon fats to the downstream chemicals.
3. The 20 carbon chemicals competing for membrane space.
Why equal amounts - because the 18 carbon plant based fats occur in more of less equal quantities in plant matter with the exception of plant reproductive material (seeds and nuts etc) which are scarce and seasonal.
Author Omega Six The Devils Fat.
Thank you for your reply. One more question: if a person is consuming sufficient omega-6 and twenty times more omega-3, do you think something bad would happen?
You may have difficulty clotting if you eat a large excess of n-3. That's one problem that traditional Inuit had. They'd get a nosebleed that wouldn't stop for 3 days.
"...the ratio of omega-6 to omega-3 fatty acids in the diet is the crucial factor for mental and physical health, rather than the absolute amount of each."
Chris Masterjohn and I argue that it's more complex than just ratio. The amount of each also matters. A low intake of PUFA makes the ratio matter less and a high PUFA intake makes it matter more. You can show all the interventions you want. If they don't control for total PUFA intake, they don't prove that the ratio is the key factor. Then just show that the ratio matters if you eat a diet filled with PUFAs, like most Western people do.
Coconut oil has no omega-3, but it is low in PUFAs. Safflower oil has a high omega-6 ratio, and has very high PUFAs (80%). To say that only the ratio matters, you are saying that coconut oil is no better than safflower oil. Try eating 4 tbs of each oil a day and tell me there's no difference in the inflammation.
Also, you have to control for carb intake, which may make the problem worse. Esp the refined sugars and rancid flours most people eat. You can't verify that the ratio is the key issue, unless you control PUFA intake, carb intake, the intake of refined carbs, and other relevant factors. I don't eat fatty fish or fish oils and have no inflammatory problems that you claim are cured by omega-3 and caused by omega-6.
I agree with you for the most part. I was stating Dr. Lands' hypothesis, not my own. I think you'll have less of a problem with my next post.
"Based on the epidemiology in this post, Drs. Hibbeln and Lands state that 3.7 g/day of fish oil would be enough to restore an acceptable 6/3 ratio to the average American (similar to Japanese), despite the high n-6 intake."
The last phrase bothers me. Why go to the expense of omega-3 oils, if one can get the same benefits from eliminating PUFA vegetable oils as well as limiting other foods which are high in PUFAs? It seems like a cop-out. The first step IMO should be to eliminate all high-PUFA oils and foods, forever. (That includes nuts and seeds, most of which have sky-high PUFA levels.)
To take omega-3s merely to counter omega-6 is an allopathic solution. It provides a drug-like effect, by blocking omega-6 metabolites. That only provides short-term benefits. In the long-term, omega-3 oils are more toxic than omega-6, esp if we are exposed to pollution.
The most anybody needs is 0.1-0.5% PUFAs by calories, according to an excellent report, written by Chris Masterjohn. That's for pregnant or nursing women and children. Adults need little or no PUFAs.
I think you, Dr. Lands, Dr. Hibbeln and I are in agreement. Lands and Hibbeln are all about reducing n-6. They aren't saying that adding fish oil to the standard american diet is the best solution, only that it could help somewhat.
Great post Stephan.
I will respond tomorrow, The computer took time out during the first attempt. (-:
Bruce K wrote:
"The first step IMO should be to eliminate all high-PUFA oils and foods, forever. (That includes nuts and seeds, most of which have sky-high PUFA levels.)"
That would not be wise. Regular nut consumption is associated with hugely reduced heart disease risk.
I am just starting to learn about the omega ratio. I have a question for you:
If I grind up nuts and seeds--using quantities that respect a 2:1 ratio or less--am I on the right track? I know fish oils are great...but, I like to add nuts and seeds to my oatmeal. Just curious...
I think you are on the right track. I would avoid eating too much PUFA in general however.
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