Thursday, April 24, 2008

Scientist Discovers that Only Pills can Control Hypertension

I went to a presentation today by a prominent hypertension researcher. His talk began with a slide that had two pictures side-by-side: one of the late fitness advocate Jim Fixx, and the other of Winston Churchill. Fixx was a marathon runner, while Churchill was inactive, overweight and had a famous appetite. Fixx died of a sudden heart attack at 52, while Churchill lived to 90. The presenter went on to state that this is an example of how genes control CVD risk, implying that despite Fixx's exemplary lifestyle, his genes had condemned him to an early death.

I wanted to jump up and yell "I think you're leaving out the alternate hypothesis: running marathons and stuffing yourself with grains isn't healthy!" But instead I suffered quietly through what ended up being an inane yet informative presentation.

His lab looks for gene variations that affect blood pressure (BP). There's a huge amount of money and research going into this. His lab and others have come up with two classes of mutations:
  • Common allele variants that have an insignificant but measurable effect on blood pressure.
  • Rare genetic mutations that have a significant effect on BP. The most common affects 1 in 2,000 people in the US.
Despite truckloads of funding and research, they have yet to uncover any gene or combination of genes that accounts for even a fraction of hypertension in Americans. So what's the next step? Keep looking for genes.

I suspect they will never find anything interesting. The reason? Hypertension is tightly linked to lifestyle. It's a quintessential aspect of the "disease of civilization". It's highly responsive to carbohydrate restriction, as a number of clinical trials have shown. Remember the Kuna? They don't get hypertension when they live a non-industrial, grain-free lifestyle (despite eating more salt than the average American), but as soon as they move to the city their hearts explode. It's been demonstrated in a number of other similar cases as well. Genetics are clearly not responsible.

Don't get me wrong, I do think genetics can modify a person's response to a poor lifestyle. But when the lifestyle is healthy, the vast majority of these differences fade away. I have a more thorough discussion of this point here.

If you give just the right dose of poison to a group of animals, 50% will die and 50% will survive (called the EC50 dose). You might then conclude that genetics had determined who lived and died. You wouldn't be wrong, but you'd be missing the point that what killed them was the poison.

The thing that really bothers me about this thinking is it's disempowering. The presenter suggested that the reason for the difference between Fixx and Churchill was their genes. If genes have us in such a tight grip, why bother trying to live well? The only logical solution is to pop hypertension pills and eat cake all day.

My guess is that if they had lived a more natural lifestyle, Fixx would have made it to 90 and Churchill would have been fit and lean.

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