Tangentially related to the question of the nature of polar bear adaptations to their environment and diet, I was looking into an on-going argument about the health-effects of certain high-fat diets on humans.
In particular, the simultaneously much maligned and praised “Atkins” style diets, high in protein and animal fats from animal meat have occasionally seen renewed popularity. An argument I have often come across on the pro-meat/fat side of the debate is the fact that Eskimos who persist for extended periods of time on extremely high-fat diets derived from whale and seal blubber don’t seem to exhibit any adverse health effects such as increased rate of heart disease, high LDL cholesterol and so on.
This argument is invoked to rebut the claim that diets high in animal (saturated) fats are the cause of heart disease, or that high blood cholesterol is a cause of (as opposed to caused by) heart disease.
So the argument basically goes that, if it was really the case that eating lots of saturated fats cause heart disease (and/or high LDL blood cholesterol), then we should expect to see this manifest in much higher rates of heart disease in eskimo populations who eat lots of seal and whale blubber.
This got wondering, what is the fatty acid composition of whale and seal blubber?
It took me a while, and I’ll have to go dig up some references again if somebody wants to see them, but I managed to find some articles where the fatty acid composition of (in this case whale) blubber was analyzed. Turns out whale blubber is actually very high in healthy polyunsaturated fats, ala fish-oils you also find in fatty fish like Salmon, Herring and so on, which is known to actually increase good HDL blood cholesterol, and decrease bad LDL cholesterol, and which in countless studies is positively correlated with good cardiovascular health.
This of course completely undermines this particular argument for the pro-animal-fat side of the debate.
In light of this it is possible that some of the polar bear adaptations to a high fat diet does not necessarily imply selection against heart disease, but rather just adaptations to fat transport and metabolism. Getting fat out of the bloodstreams and into muscles and adispose tissues simply for reasons of improved storage and ease of use. The fatty acid composition of a diet high in whale and seal blubber could in effect all by itself reduce the risk of heart disease.
@Rumraket good thoughts. It is also possible that:
Eskimos have a better balance between calorie consumption and utilization, and this reduces risks.
Eskimos are genetically adapted so as to better process fats, similar to how we were considering so for polar bears.
I’m skeptical of the unsaturated fats being protective the way you suggest, but these are all valid hypothesis to test. As for selecting for better processing of fat vs. against heart disease, these might merely be two sides of the same coin. I’m not sure they are seperable in meaningful way.
Makes sense. I wouldn’t claim to know which of these options, if any, are the case.
I’m skeptical of the unsaturated fats being protective the way you suggest, but these are all valid hypothesis to test.
I’m just relaying what I have often read, that there is evidence that suggests that some types of fats actually have a protective effect against other types of fats. Particularly the types of fats found in different types of nuts, like hazel, walnuts, and almonds. And fatty fish.
As for selecting for better processing of fat vs. against heart disease, these might merely be two sides of the same coin. I’m not sure they are seperable in meaningful way.
I see what you mean. Selection for improved lipid handling would inadvertently also be protective against heart disease.
Yes, I am a medical doctor. I know about this hypothesis, and I have skepticism towards it as an explanation of Eskimos lower cardiovascular risk. Caloric balance has a huge impact, as does intermittent fasting. So I’d expect those to be the reason. At the very least that is the null hypothesis for me.
For example this one:
Dahl, T., Lydersen, C., Kovacs, K. et al. (2000): Fatty acid composition of the blubber in white whales (Delphinapterus leucas) Polar Biol (2000) 23: 401. https://doi.org/10.1007/s003000050461
Please, please stop using the pseudoscientific framing of this as a mere argument. You are missing a great opportunity to teach laypeople the difference between science and pseudoscience. By adopting the pseudoscientific framing, you allow laypeople to shrug and say, “Same evidence, different interpretation. Which person do I believe?”
Here’s a far better framing IMO:
Behe has advanced a testable hypothesis.
His bizarre misunderstanding of the term “missense” has created an opportunity.
Behe doesn’t know whether the polar bear APOB alleles have reduced or increased function–we don’t either!
However, since Behe erroneously thought that the APOB data supported his hypothesis and cited it, we can all agree completely that his hypothesis predicts that the polar bear APOB alleles will have reduced function. There’s no wiggle room.
Since there is potential for relevance to hypercholesteremia, someone will test these alleles functionally very soon.
We need to wait until we have the functional data, and only then we can be certain whether Behe’s hypothesis is supported or disproved.
Superdeterminism in the physics literature usually means that the “free will” assumption (not having to do with free will strictly speaking, but about whether experimental parameters can be set independently of other initial conditions) is not satisfied. But QM doesn’t actually rule out that the physical universe is deterministic even if the “free will” assumption still holds.
Also, on some versions of Molinism, God could still make that pool shot even if there is fundamental indeterminism in the laws of physics. Omniscience is useful like that.
This is incorrect, though a common misunderstanding. Local theories are ruled out. Non-contextual theories are ruled out. But hidden variables are still on the table, and one of them is arguably simpler, and conceptually far more clear, than the orthodox interpretation.