Thrifty gene is bankrupt science? Or, why you should always be suspicious when you hear …
|February 28, 2011||Posted by O'Leary under Evolutionary psychology, Genetics|
As Globe & Mail medical reporter Carolyn Abraham tells it (February 25, 2011):
Since James Van Gundia Neel proposed it almost 50 years ago, the thrifty-gene hypothesis has reigned as the dominant explanation for soaring rates of obesity and diabetes among many aboriginal groups. Native communities where diabetes didn’t exist in the first half of the 20th century had, by the end of it, the world’s highest prevalence, with Arizona’s Pima Indians in first place, followed by the Nauru islanders of Micronesia and the Oji-Cree at Sandy Lake.Dr. Neel, an influential geneticist at the University of Michigan, felt that genes were partly to blame. He speculated that genetic traits among the world’s prehistoric hunter-gatherers enabled them to store calories during times of feast in order to survive in times of famine.
But with “the blessings of civilization,” he wrote, these thrifty genes had become hazardous baggage in a sedentary world of all feast and no famine, predisposing carriers to obesity and the diseases it brings.
His idea spread like an epidemic, embraced by everyone from public-health officials and policy-makers to the media and many aboriginal people themselves. Although never billed as more than a hypothesis, it came to be seen as fact – “a scientific axiom,” Dr. Hegele says, “dogma almost.”
But now, with obesity and diabetes shaping up to be a global pandemic, the theory appears to be dying – raising the prospect that prejudice more than proof gave it such a long life.
Why you should always be suspicious when you hear … what? Here’s what: When you hear any medical thesis whatever that is based on what “prehistoric hunter-gatherers” supposedly did.
You need to monitor three simple devices to track the growth of diabetes:
Cupboard/cold storage: For research subjects, observe and rate contents, against published food guides.
Weigh scales: Weigh research subjects at regular intervals; record results against body mass index measures.
Couch/TV combo: Clock use by subjects.
In some households, the research team itself is at risk for diabetes just from making observations. And this is indeed a worldwide, multicultural problem.
As one commenter pointed out, it isn’t fair to assume that the spread of the thrifty gene idea was prejudice. Chances are, it was motivated in large part by a wish to blame something other than lifestyle, lest one seem to criticize.
No fear, anyone can increase their personal risk of diabetes by following a diabetes-prone lifestyle. Lifestyle diseases are equal opportunity predators.
By the way, if the “thrifty gene” is one of the triumphs of “evolutionary medicine” (EM), I am glad if EM is not in the health care budget.
One wise doctor says, diabetes happens when people outgrow their pancreases. There, you heard it, and it is not evolutionary medicine.
Note: Thanks to commenter SCheesman for putting me on to this. Read the Globe, do ya, Cheesman?