For those of you who haven't been reading the comments, we've been having a spirited discussion about the diet and health of hunter-gatherers here. I brought up the Kuna indians in Panama, who are immune to hypertension, live a good long time, do not gain excess weight, and seem to have less cardiovascular disease and cancer than their city-dwelling cousins.
I was hungry for more information about the Kuna lifestyle, so over the last few days, I've dug up every paper I could find on them. The first paper describing their lack of hypertension was published in 1944 and I don't have access to the full text. In 1997, a series of studies began, headed by Dr. Norman Hollenberg at Harvard. He confirmed the blood pressure findings, and collected data on their diet, lifestyle and kidney function. Here's a summary:
The Kuna are half hunter-gatherers, half agricultural. They cultivate plantains, corn, cocoa, yucca, kidney beans, and several types of fruit. They trade for sugar, salt, some processed cocoa and miscellaneous other foods. They drink 40+ oz of hot cacao/cocoa per day, some locally produced and some imported. A little-known secret: the Kuna eat an average of 3 oz of donut a week. They also fish and hunt regularly.
In the first recent study, published in 1997, the Kuna diet is described as 29% lower in fat than the average US diet (56 g/day), 23% lower in protein (12.2 g), 60% higher in cholesterol, and higher in sodium and fiber. The study doesn't specifically mention this, but the reader is left to infer that 65% of their calories come from carbohydrate. This would be from plantains, corn, yucca, sugar and beans. The fat in their diet comes almost exclusively from coconut, cocoa and fish: mostly saturated and omega-3 fats.
In the next study, the picture is slightly different. Their staple stew, tule masi, is described as being 38% fat by calories (from coconut and fish), exceeding the American average. In the final study in 2006, Hollenberg's group used a more precise method of accounting for diet composition than was used in previous attempts. The paper doesn't report macronutrients as a percentage of calories however.
I was able to find some clues about their diet composition. First of all, they report the meat consumption of the Kuna at approximately 60 oz per week, mostly from fish. That's 8.6 oz per day, identical to the American average.
By putting together the pieces from the later studies, a new picture emerges: a diet high in fish and moderate in protein, moderate in unprocessed fat (especially saturated and omega-3), and moderately high in mostly unprocessed carbohydrate.
Here's my interpretation. The Kuna are healthier than their city-dwelling cousins for a number of reasons. They have a very favorable omega3:6 ratio due to seafood, wild game and relatively saturated vegetable fats. Their carbohydrate foods are mostly unprocessed and mostly from non-grain sources. They also live an outdoor life full of sunshine (vitamin D) and exercise. The chocolate may also contribute to their health, as it contains high levels of potentially protective polyphenols. They're healthier than industrialized people because they live more naturally.
Another lesson to be learned from the Kuna and other exceptionally healthy indigenous peoples is that the human body can tolerate a large amount of carbohydrate under the right conditions.
17 comments:
Thanks for the update Stephan. As you're well aware, there is just too much out there to read.........
Peter
PS btw the Kitavans were up at 69% calories from carbs, but with many of the favourable aspects you mentioned. Except they almost all smoked too!
Thanks, Stephan. This is a really good example of how to read a study. You have to look at every piece of it, not just the abstract or conclusions, and you have to take it in context with other studies. Too many people (most of them journalists) forget this.
Peter, smoking is a two-edged sword. I am not advocating smoking in any way, shape, or form, but it's undeniable that it helps people manage their weight. I think Taubes claims it increases insulin sensitivity. That could help explain all these people on high-carb diets like the French and the Kitavans who don't become obese and diabetic.
Today I'm going on a blog diet - only reading one new blog entry. Stephan, you're it! (Tomorrow I'll pick someone else.)
Peter,
I went back and read your Kitava posts. It's all very interesting. Maybe HDL and trigs are just markers of carb consumption that merely correlate with insulin disturbances in Western cultures. Do you think insulin is the missing link here? The investigators didn't measure insulin or blood glucose in the Kuna, but I can only assume they're both low, given their total lack of overweight and diabetes.
Migraineur,
I'm flattered! Why the blog diet? Was blog-surfing taking too much time away from work?
You've made a pretty solid case for the health benefits of a hunter-gatherer diet.
This is slightly off-topic, but I was thinking there's probably also much we can learn from the social aspect of hunter-gatherer societies such as closer family and community interaction, relationship to nature and perhaps even spirituality.
Yes, I think high trigs and low HDL are simply a marker of carbohydrate in take. If you are insulin resistant, which is a hallmark of aging in "Westernised" societies, then because high trigs and low HDL are markers that you are living at a high carb intake, that may well put you beyond the carb intake at which you can remain normoglycaemic. IR also increases the insulin needed to process whatever carbs you do eat, making for hyperinsulinaemia, well beyond physiologically acceptable limits.
Hyperglycaemia and hyperinsulinaemia seem to be at the root of most chronic diseases.
Of course if you eat LC and have low trigs and high HDL, well that's fine for most levels of IR.
Which leaves the question of what IS insulin resistance... LC obviously side steps it, what causes it?
What if it's not diet????????
Peter
Peter,
That makes a LOT of sense.
It's an interesting question, the reason behind insulin resistance.
I suppose it doesn't necessarily have to be caused by diet, although as you said it can be sidestepped by reducing carbohydrate.
Here are some things I can think of that might contribute: vitamin D status. Omega-3:6 ratio. Exercise. Stress level. Perhaps also a contribution from phytate affecting zinc status and other minerals?
Reid,
I agree there's probably a lot to be learned from them socially. Apparently they're big on rites of passage.
Yes, too much time spent blogging. But the blogs I hit are so much more interesting than what I do for a living.
>sigh<
Stephan,
Two other possibilities, high doses of fructose hit the liver and get converted to LCFA pdq, intracellular triglycerides in muscle are a potent and physiological stimulus to develop IR. If they do the same in liver there is the start of a domino effect of hepatic insulin resistance, glucose dumping etc etc.
The other is the insulomimetic effects of wheat (and other???) lectins. If a food chemical is hitting the intracellular downstream insulin pathways, that's a pretty good stimulus to downregulate your cell surface insulin receptors.
Of course there's a lot of talk about plasticisers etc, indirectly feeding in to diet. Once you are contaminated LC looks to be the only answer here.
It's stuff like this that has me not completely binning Ornish and Co. Except the whole grain garbage of course. And the fruit. And the idiocity from some quarters about animal fats being carcinogenic. And...
Peter
Interesting findings. I'm surprised at the high intake of meat, fat, and salt. Points well taken about natural, unprocessed diet and exercise. Reid, I also think there are big social factors. I think we live in a society that gently pushes individuals towards isolation, lethargy, fear, and stress.
Two factors of stress that determine how much it affects the mood & immune function are predictability and controllability. I think in westerized societies we do worse on both measurements. Look at what's in the news right now ... we're panicking that our retirements might be screwed because of the whims of collective freemarket trading and/or decisions made at a penstroke by the fed. We think that if the right candidate becomes our leader everything will be great, and if the wrong one does then everything will be a disaster. Terrorists!
Peter,
Does fructose cause more LCFA synthesis than glucose? I'm interested in the lectin idea; I'm going to go back and re-read your posts on that. Basically the issue is, can enough of it get into your bloodstream to have a significant effect on insulin signaling?
Ross,
I've often wondered about the controllability thing. It seems to me HGs would have been at the whim of nature
Whoops, let me finish that thought.
I'm not convinced that HGs have any more control than we do. We can pretty well expect to live to 70 in the US, while a true HG doesn't know if she'll fall off a cliff tomorrow.
I think what differs may be our reaction to a perceived lack of control. Maybe they are better able to accept a lack of control than we are.
HGs can live to 75, as you pointed out earlier. I don't know what their average life expectancy is. While we may live to ~70 on average, any of us could go at any time due to homicide, auto accident, heart attack, etc. Whose life is riskier?
I think that one factor contributing to an uncontrollability factor in our lives is how insulated we are from adverse consequences of our actions. If the outcome of a situation is independent of our actions taken, then the situation is uncontrollable. Some examples... We live in cities so large that you can litter, be rude, etc and it never has any consequences on your reputation. We are so far removed from our food source that we can pollute and it has no apparent immediate effects. We can drive to work and there is no immediate effect on global warming. Our country can go to war and there is no draft; we don't even images of the dead. We have insurance for health, car accidents, fires, even death - so that if something bad happens to you, you (or your survivors) get a payoff to offset the economics of the loss.
In many of these cases (like being able to litter in our city), loss of control doesnt really threaten or harm us in any direct way. But it could hurt us in more subtle ways. Being exposed to controllable stressors that one learns to master, will lessen the effects of future uncontrollable stress. There is evidence for this phenomenon in lab rats, and a belief of it in child psychology literature - called "mastery effects".
I see what you mean. Don't you think being at the whim of nature would be an uncontrolled stress as well though? If a tree falls on your hut, that's it.
As a side note, I'd like to point out that the Kuna aren't really true HGs. They're half HG, half agricultural. I think I may have gotten that mixed up in the comments.
HG cultures may or may not have comparable lifespans to our own, but I sometimes feel our society places too much of an emphasis on longevity over wellness and quality of life. Acceptance of death is an aspect that differs in terms of the spiritual outlook of shamanic HG cultures and most Judeo-christian cultures. The shamanic presence in a society could also allow them to deal more flexibly with the occasional chaotic events of nature.
"Peter, smoking is a two-edged sword. I am not advocating smoking in any way, shape, or form, but it's undeniable that it helps people manage their weight. I think Taubes claims it increases insulin sensitivity"
I think you confused insulin sensitivity with insulin resistance. Do a search on the subject, and you'll see a thousand citations to reaseach & insulin resistance.
Losing weight as a result of super low calories is not only horrible for your health.... which further compounds the other aspects... but VLCD lifestyles are horrible for staying trim. You lose more muscle than fat, which results in the skinny-fat, sickly look, and the moment you start eating normally, you gain fat much, much faster.
Hollenberg's research on cacao is fantastic as well.
I came across a disturbing discussion about raw cacao being toxic. I appreciated your article regarding the Kuna Indians (even though that was almost 2 years ago).
Harvard did a study of the Kuna's and contributed their consumption of cacao to better brain function in the elderly. http://www.medsci.org/press/cocoa.html
Based on this study I began giving my autistic son raw cacao as it is supposed to increase blood flow in the brain. Hopefully it's helping.
Sharon
In response to Sharon's concern "about raw cacao being toxic" - chocolate contains elements (theobromine and caffeine) that are toxic to many dogs and cats. Humans, however, are able to break down and excrete those components so they are safe for us. I wonder if that is what you are referring to? I eat a lot of dark chocolate and I've never heard about the toxicity concern you mentioned.
Great article about the Kuna Indians! Thanks.
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