Wednesday, November 26, 2008

Health is Multi-Factorial

Thanks to commenter Brock for pointing me to this very interesting paper, "Effects of fish oil on hypertension, plasma lipids, and tumor necrosis factor-alpha in rats with sucrose-induced metabolic syndrome". As we know, sugar gives rats metabolic syndrome when it's added to regular rat chow, probably the same thing it does to humans when added to a processed food diet.

One thing has always puzzled me about sugar. It doesn't appear to cause major metabolic problems when added to an otherwise healthy diet, yet it wreaks havoc in other contexts. One example of the former situation is the
Kuna, who are part hunter-gatherer, part agricultural. They eat a lot of refined sugar, but in the context of chocolate, coconut, fish, plantains, root vegetables and limited grains and beans, they are relatively healthy. Perhaps not quite on the same level as hunter-gatherer groups, but healthier than the average modernized person from the point of view of the diseases of civilization.

This paper really sheds light on the matter. The researchers gave a large group of rats access to drinking water containing 30% sucrose, in addition to their normal rat chow, for 21 weeks. The rats drank 4/5 of their calories in the form of sugar water. There's no doubt that this is an extreme treatment. They subsequently developed metabolic syndrome, including abdominal obesity, elevated blood pressure, elevated fasting insulin, elevated triglycerides, elevated total cholesterol and LDL, lowered HDL, greatly increased serum uric acid, greatly elevated liver enzymes suggestive of
liver damage, and increased tumor necrosis factor-alpha (TNF-alpha). TNF-alpha is a hormone secreted by visceral (abdominal) fat tissue that may play a role in promoting insulin resistance.

After this initial 12-week treatment, they divided the metabolic syndrome rats into two groups:
  • One that continued the sugar treatment, along with a diet enriched in corn and canola oil (increased omega-6).
  • A second that continued the sugar treatment, along with a diet enriched in fish oil (increased omega-3).
The two diets contained the same total amount of polyunsaturated fat (PUFA), but had very different omega-6 : omega-3 ratios. The first had a ratio of 9.3 (still better than the average American), while the second had a ratio of 0.02, with most of the omega-3 in the second group coming from EPA and DHA (long-chain, animal omega-3s). The second diet also contained four times as much saturated fat as the first, mostly in the form of palmitic acid.

Compared to the vegetable oil group, the fish oil group had lower fasting insulin, lower blood pressure, lower triglycerides, lower cholesterol, and lower LDL. As a matter of fact,
the fish oil group looked as good or better on all these parameters than a non-sugar fed control group receiving the extra vegetable oil alone (although the control group isn't perfect because it inevitably ate more vegetable oil-containing chow to make up for the calories it wasn't consuming in sugar). The only things reducing vegetable oil and increasing fish oil didn't fix were the weight and the elevated TNF-alpha, although they didn't report the level of liver enzymes in these groups. The TNF-alpha finding is not surprising, since it's secreted by visceral fat, which did not decrease in the fish oil group.

I think this is a powerful result. It may have been done in rats, but the evidence is there for a similar mechanism in humans. The Kuna have a very favorable omega-6 : omega-3 ratio, with most of their fat coming from highly saturated coconut and cocoa. This may protect them from their high sugar intake. The Kitavans also have a very favorable omega-6 : omega-3 ratio, with most of their fat coming from coconuts and fish. They don't eat refined sugar, but they do eat a tremendous amount of starch and a generous amount of fruit.

The paper also suggests that the metabolic syndrome is largely reversible.

I believe that both excessive sugar and
excessive omega-6 from modern vegetable oils are a problem individually. But if you want to have a much bigger problem, try combining them!


Anonymous said...


Thanks for another great post. I have recently been reading opinions from various sources that omega 3 supplementation through fish oil or other means will likely only help persons who consume way too much omega six. These sources further opine that persons who consume an appropriately low amount of omega six will not be helped by omega 3 supplementation, and may even be harmed thereby. They therefore recommend that the optimal way to balance 3 and 6 is to reduce 6, as opposed to increasing 3. Do you have an opinion on this issue? Do you believe in keeping PUFAs as low as possible in general? And how "essential" are the EFAs?

Robert Andrew Brown said...

Great posts Stephan.

Excess Omega 6 lack of Omega 3 combined with high fructose and sucrose has a lot to answer for.

"Saturated" fat from naturally reared animals is not the problem. The problem is excess Omega 6 and lack of 3 (mother and long chain.

We only need between 1/2% and 2% of calories of the plant based 18 carbon Omega 6 linoleic acid. We are eating 8-13%. We are running the body outside any previous dietary experience and it's specs.

Result - Breakdown.

The term saturated fat is loosely used.

The body is immensely sensitive to Omega 6 intake levels.

Most examinations of saturated fat intake take no account of the extra Omega 6 rising saturated fat intake comes with.

Omega Six (vegetable Oil) cooking fat (saturated) intake has increased massively.

Omega Six content of grain fed animals has increased significantly.

So often I suspect population statistics and human `trials' looking at saturated fat are in fact looking at rising Omega 6 and derivatives including artificial trans fats.

Add mineral depletion,loss of fat soluble vitamins (thank you for highlighting their importance)and you have answers for a good part of the increasing levels of western conditions.

Robert Brown

Author Omega Six The Devils Fat

Robert Andrew Brown said...


Re your question.

1. You need to split those with a historic adequate Omega 3:6 balance, from the average westerner.

The average westerner will benifit from long chain Omega 3s as they will help counteract the historic excess of Omega 6, which is highly stored in body fat.[1-2 grams a day DHA and EPA combined.]

Plains gatherer
A plains gatherer would have had a low plant omega 3:6 intake and so less inflammatory pressures and so would not need as much long chain Omega 3 [even if they may have benifited from greater intake]

2. You need to split the plant based Omega 3 and 6 from the long chain fats in intake terms.

Plant based fats.

We only need 1/2-2%cals of Omega 6 plant based fats.

Omega 3 plant based intake would have been about 50% t0 70% of plant based Omega 6.

How essential are EFAs.

Totally completely and utterly fundamental to health body function, brains, behaviour, reproduction and everything.

Omega 6 is arguably the master fat and Omega 3 the restraining and complementary wife.

Robert Brown

Author Omega Six The Devils Fat

Evelyn Tribole, MS, RD said...

There is an excellent review paper on how the imbalance between dietary omega-6 fats and omega-3 fats leads to many chronic diseases, including cardiovascular disease, cancer, inflammatory and autoimmune diseases. Several mechanisms are described.

Simopoulos A. The Importance of the Omega-6/Omega-3 Fatty Acid Ratio in Cardiovascular Disease and Other Chronic Diseases, Experimental Biology and Medicine, 2008, 233 (6), p. 674.

Evelyn Tribole, MS, RD
Omega-6 Research News

Debs said...

Great post and information!

This is related to something I've been thinking about with Weston Price's research. Among the people he found who had been exposed to a Western diet, there were a great many signs of physical degeneration, but there wasn't the same kind of obesity and metabolic syndrome we see now. There also didn't seem to be as much of a problem with the omega 3:6 ratio; people were still consuming some protective n-6 foods, and there wasn't so high an incidence of vegetable oil consumption as there is now.

The combination of detrimental factors, and the reduction of protective factors, seems to be significantly more damaging than any one of those elements alone.

Food Is Love/Seattle Local Food

theoddbod said...

the n-6/n-3 ratio is important. but I wouln't stop eatin omega-6 containing foods for fear of becoming all of a sudden hyper-inflammatory, because both omega 3s and omega 6 PUFAs (just not as much as omega 3s) are able to suppress inflammatory cytokines in humans. we all just need to focus more on getting some more omega 3s in our good ol' north american diets, fish and flax will do nicely. and just like DEBS said: no single answer is ever the answer

Robert Andrew Brown said...


Excess intake of Omega 6 is a key factor.

Excess Omega 6 promotes oxidative stress and inflammation.

Omega 6 in quantity is scarce in the natural food chain. We would have had difficultly in getting 2% of calories on a year round basis. We are not designed and have no experience of higher intakes.

There is a massive breadth of evidence across many conditions.

Once you start looking at the pathways and reasons in depth it is pretty unavoidable that excess Omega 6 is a big factor in the rise in inflammatory and oxidative stress related conditions.

The lack of Omega 3 in the diet is a separate but related issue.

Robert Brown


Omega Six The Devils Fat.

theoddbod said...

there is no doubt that excesses in n-6 fats will exacerbate conditions where inflammation is involved. unfortunately, people don't eat like they are in a clinical trial or like lab rats. what I mean is that when you improve one part of your diet (eat foods with less n-6 fats) you usually are making other changes (because the food you are eating is probably healthier overall)as well, and that will also contribute to improved outcomes.
but no doubt inflammation plays too big of a role in almost every disease, so if you can reduce it in any way, go for it (naturally, that is ;))

Robert Andrew Brown said...

The Oddbod,

Thanks for the response.

I agree it is very difficult to objectively isolate the effect of individual dietary changes in humans, and so it is very difficult to draw definitive conclusions looking at individual items in the picture.

But a bit like an impressionist painting when you stand back and look at the whole the picture is much clearer. Given the complexity and interlinking of the pathways it may be that this is the approach that has to be adopted, in a sense as happened with smoking.

I also accept not much work seems to have been done on the Omega 3 eicosanoids.

Looking at things as a whole, the impact and usage of COX and LOX blockers, quite a number of varied `trials' looking at inflammatory markers and related immune system messengers (cytokines), the huge increase of Omega 6 (and loss of 3), the availability of Omega 3 and 6 in the food chain, the wider impact of Omega 6 on reproduction and behaviour, and a number of metabolic factors I think on the balance of probabilities it is highly likely part of the explanation for rising western conditions is excess Omega 6 and lack of 3.

Again thanks for your comment.

ttlaitin said...

Robert Andrew Brown:

"Omega Six content of grain fed animals has increased significantly."

do we have any statistics on exactly how much omega-6s different kinds of meats contain? or other foods?

what are the main sources of excess omega-6s in the western diet? junk food like chips or fries fried in vegetable oil?

how much omega-6s would an average lowcarb/paleo-diet contain? still too much?

Robert Andrew Brown said...

Hi ttlatin,

I hope this helps. It is a big topic and information is diffuse and has to be hunted out.

-----do we have any statistics on exactly how much omega-6s different kinds of meats contain? or other foods? -----

Figures are limited but I have found a few trials looking at animal fat composition or fat product compostion eg Swiss Alpine Cows, Greek chickens etc.

Most look at ratios rather than total fat content.

One by Simopolous comparing Greek true free range eggs to factory eggs found a difference of 10 time more long chain 3s in the true free range.

Egg yolk as a source of long-chain polyunsaturated fatty acids in infant feeding

AP Simopoulos and N Salem Jr
Center for Genetics, Nutrition and Health, Washington, DC 20009.

In this paper we compare the fatty acid content of egg yolks from hens fed four different feeds as a source of docosahexaenoic acid to supplement infant formula. Greek eggs contain more docosahexaenoic acid (DHA, 22:6 omega 3) and less linoleic acid (LA, 18:2 omega 6) and alpha- linolenic acid (LNA, 18:3 omega 3) than do fish-meal or flax eggs. Two to three grams of Greek egg yolk may provide an adequate amount of DHA and arachidonic acid for a preterm neonate. Mean intake of breast milk at age 1 mo provides 250 mg long-chain omega 3 fatty acids. This amount can be obtained from less than 1 yolk of a Greek egg (0.94), greater than 1 yolk of flax eggs (1.6) and fish-meal eggs (1.4), or 8.3 yolks of supermarket eggs. With proper manipulation of the hens' diets, eggs could be produced with fatty acid composition similar to that of Greek eggs.

Several trials suggest Omega 6 LA levels in grass fed stock of around 2%.

Livestock feed has a definite impact. This is a trial that looked at the issue.

Effect of feeding systems on omega-3 fatty acids, conjugated linoleic acid and trans fatty acids in Australian beef cuts: potential impact on human health.
Ponnampalam EN, Mann NJ, Sinclair AJ.

Department of Food Science, RMIT University, Melbourne, Victoria 3001, Australia.

In general terms grass fed animals have approaching a balance of Omega 6 LA and Omega 3 ALA in fat eg Grass fed lamb, whilst non grass fed can have big Omega 3:6 differentials - eg pork.

Industrial chick has surprisingly high levels of Omega 6. Chicken fat has about 3 grams in 28 of LA.


So in 3:6 terms a diet of salad olive oil and industrial chicken, and you would have a significant omega 3:6 imbalance.

----what are the main sources of excess omega-6s in the western diet? junk food like chips or fries fried in vegetable oil?----

The common vegetable oils and any food that contains them and surprisingly most do, are the key culprits. We have added to the problem by displacing livestock suet with vegetable suet (artificial saturates for natural saturates because we somehow see artificial vegetable saturates as healthier !!! ???).

Vegetable and derivative fat consumption per capita is frightening. In 2005 total US fat consumption was 87 lbs of which 73 was vegetable based and most of that was high 6 oils.

----how much omega-6s would an average lowcarb/paleo-diet contain? still too much?----

Difficult. It would depend mainly on seed and nut intake. Some but not all nuts and seeds are very high in Omega Six.

Also it would depend on what meat was eaten, how the animals were raised, and what cuts. Grass fed should be OK but grain fed would likely result in 3:6 imbalances and excess 6.

All of which raises lots of difficult issues of quantity v quality, and would we be healthier eating quality suet etc rather than feeding industrial suet back to cows?

Robert Brown

Author Omega Six The Devils Fat

Stephan Guyenet said...


I think reducing omega-6 is the best single thing you can do. But it's also important to get omega-3s because even if you eat very little 6, your ratio can still be bad. People like to talk about how omega-3 is easily oxidized, which it is, but what they often leave out is the profound antioxidant effect it exerts in the cell. I'll post more on this soon.

Healthy cultures around the world have proven that, at least in certain dietary contexts, a relatively high intake of omega-3s from animal sources is healthy and safe.

I get the impression that it would be very difficult to become EFA deficient, although it's exceptionally easy to become EFA-imbalanced in the modern world. See Robert's comment above.


Good point, the term "saturated fat" is definitely loosely used to apply to anything that contains more than a small amount of it.


Agreed. It would be interesting to be able to tease out exactly which elements of the diet changes caused which symptoms. I have a few guesses...

Unknown said...


Glad you liked the study. I thought it was quite interesting too.

Quick question for you, maybe worthy of a short post so it gets more attention: what sources do you like for recipe ideas? Any good cookbooks? I'm thinking specifically of your Real Food IX post. I've never heard of those before, or even seen non-bread/beer recipes that use fermentation.

Warm regards,

Unknown said...

Oops, forgot to Checkbox follow-up comments ...

Stephan Guyenet said...

Hi Brock,

I get my recipes from all over the place. Some of my favorite cookbooks are "Nourishing Traditions", "Wild Fermentation" and "Joy of Cooking". Other than that, I often come across new dishes while I'm reading about one culture or another, look them up on the internet and try them out.

daiikkon said...

Hi Stephan,

Do you think juicing beets or carrot could be too high in fructose?

Stephan Guyenet said...

Hi Daiikkon,

Carrots and beets to contain some sugar (about half fructose if you include the sucrose portion), but not as much as a fruit. I wouldn't worry about it unless you drink a lot of vegetable juice, or if you eat a lot of sugar on top of it.

Helen said...

I know this was a long time ago, but I just found it. Great post, as usual - and very helpful. Since seeing Dr. Lustig's fructose video I've been phobic of sugar. But I have no significant sources of omega-6 in my diet now and a lot of omega-3 and saturated fat, so perhaps a little dab of fructose won't do me in. (I also wonder what the results would have been with trading saturated fat alone for the vegetable oils.)