I found a a mortality table from the records of a Russian mission in Alaska (compiled by Veniaminov, taken from Cancer, Disease of Civilization), which recorded the ages of death of a traditionally-living Inuit population during the years 1822 to 1836. Here's a plot of the raw data:
Here's the data re-plotted in another way. I changed the "bin size" of the bars to 10 year spans each (rather than the bins above, which vary from 3 to 20 years). This allows us to get a better picture of the number of deaths over time. I took some liberties with the data to do this, breaking up a large bin equally into two smaller bins. I also left out the infant mortality data, which are interesting but not relevant to this post: 
Excluding infant mortality, about 25% of their population lived past 60. Based on these data, the approximate life expectancy (excluding infant mortality) of this Inuit population was 43.5 years. It's possible that life expectancy would have been higher before contact with the Russians, since they introduced a number of nasty diseases to which the Inuit were not resistant. Keep in mind that the Westerners who were developing cancer alongside them probably had a similar life expectancy at the time. Here's the data plotted in yet another way, showing the number of individuals surviving at each age, out of the total deaths recorded:
It's remarkably linear. Here's the percent chance of death at each age:
In the next post, I'll briefly summarize cancer data from several traditionally-living cultures other than the Inuit.
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6 comments:
Hi Stephan,
Thanks for pulling the numbers out. A few made it to 100 years of age I see. While I don't doubt the toxicity of rancid vegetable oil, the total dose of omega three PUFA in this population is moderately high. Stefansson does describe the delicacy of rotted fish in seal oil. The Eskimo equivalent of Stilton. This makes me cautious about the frank toxicity of all PUFA, especially as the Inuit on their native diet did seem to be fairly free of chronic degenerative diseases.
Peter
Peter,
I totally agree. I have a hard time believing that omega-3s from fish are harmful because of this. I think the problem with vegetable oil is something more specific (like the n-6), not the fact that it's polyunsaturated. Although I will say that the Inuit have a tendency to bleed a lot (nosebleeds lasting for several days for example), which they say results from the "blood thinning" omega-3s.
It's interesting to see that they have a maximum lifespan similar to ours today, even if the mean is lower.
Thanks for the data Stephan – it always irks me that the mean lifespan is quoted as with no regard for child mortality and infectious diseases. Perhaps one of the confounders in the PUFA issue is that the polyunsaturation index of nut oils and fish increases the further away you get from the equator. Perhaps people in colder climates can tolerate higher PUFA than those in warmer regions – possibly different D6D mechanisms?
Hi Frank,
I agree, not taking infant mortality into account really makes the data misleading.
I've often thought about the fact that saturation decreases further from the equator. When you get close to the equator, you either have to get saturated or get antioxidants (coconut vs red palm oil)! I'm not sure that applies to mammal fat though, since we're warm-blooded.
Fish fat is polyunsaturated everywhere, and even tropical populations near the equator who ate lots of fish/fish eggs seemed to do just fine. I think the most parsimonious explanation is that polyunsaturated fat in the form of fish oil is fine.
Oh yes, American Indians in the Pacific Northwestern US used fish oil liberally as a cooking fat (rendered candlefish and salmon oil). No household was complete in some tribes without a big jug of fish oil. I don't have any hard data to support the claim that they were healthy, but the anecdotal evidence does support it.
Thanks for sharing those numbers. I've always countered the typical longevity argument with the view that quality of life is preferable to quantity. But if you can have both, even better.
Hi Stephan
Apparently things like whale and seal blubber differ widely in terms of fatty acid composition according to geographical location, but separating what they eat from temperature zone would be all but impossible without a prospective trial.
Fish fat is mostly polyunsaturated but omega-3 seems to predominate in cold-water fish.
The fish oil for cooking throws up a conundrum - surely it would quickly oxidise and according to Ray Peat's work contribute to degenerative disease. One thing not factored into PUFA studies is the use of synthetic BHA vs natural vitamin E - surely a large confounding factor?
I find it interesting though that Pacific Island peoples eating raw fish in coconut cream did okay for millennia, but are scared away from this (I have to say rather yummy) traditional dish by the anti-satfat cabal. Since eating a very similar diet to SAD their rates of type 2 diabetes have soared (and they have a much higher rate of complications) - it's very tragic. Food is such a major part of PI culture and the dietary advice doled out by the RDs is both physiologically and psychologically damaging.
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