Monday, 07 January 2013

Medical science asked to consider evolutionary biology

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Humanevolotionarybiology“We’ve been selected not necessarily to be healthy, but to reproduce and much of what we’re treating are compromises that have been made in our evolutionary biology for just that reason"—Prof Bunt. Image: iStockA leading expert says the study of human health could be significantly advanced if evolutionary biology were applied as an essential science to medical research.

UWA School of Anatomy, Physiology and Human Biology’s professor Stuart Bunt says far from being perfectly adapted biological machines, humans may actually be examples of “unintelligent design”, selected to be variable and imperfect which is the cause of many of our health challenges.

He says the link between evolutionary biology and modern medicine may illuminate some of the causes of health defects, which he says are the result of compromises in our evolutionary history.

“Many of our health problems are not the result of us “wearing out”, but have more to do with compromises that have been made in our evolution,” he says.

“It’s important for medical practitioners to consider some health problems are not due to our bodies breaking down as such, but actually what we’ve been selected for.

“We’ve been selected not necessarily to be healthy, but to reproduce and much of what we’re treating are compromises that have been made in our evolutionary biology for just that reason.”

Prof Bunt says there is an urban myth of the efficiency of nature or the beauty of natural design, however evolution doesn’t necessarily produce efficiency, it produces whatever is needed to survive and that can be counter-productive for human health. 

“As you see in places like Australia where human beings eat very high protein and high calcium diets, people get very big,” he says.

“But as you get older that tends to lead to heart disease, and these areas have some of the highest heart attack rates in the world.

“But in evolutionary terms, it all makes sense because you never lived to be very old, you would be big and healthy as a hunter and big and healthy to reproduce and have lots of offspring, and then you would die at 30-35, women would die normally in child birth at around age 40.

“Perhaps one in ten, one in twenty people lived to be 80 which is just about as many grandparents as you needed to look after the kids.

“If you’re a hunter-gatherer tribe you maybe need two to three elderly people back at camp to look after 20 little kids while you’re off hunting.

“So, you select for the fact that most people are going to die at 40, big and healthy, a few people will survive through to 80 or 90 and that’s the most efficient way of doing it.”

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