I Blame The Parents

By Neville Elder 12/16/14

How Mother Nature kept us alive by teaching us to love booze.


If alcohol is so bad for us then why do we drink it? Matthew Carrigan at the Department of Natural Sciences in Gainesville, Florida might have the answer. He is a biochemist working in a relatively new field of science called paleogenetics. He looks at the DNA in modern humans and our primate relatives, gorillas and chimpanzees, to find out how our genome evolved in early man and our distant ancestors. 

When did we have our first taste of the hard stuff? A quick look around the modern world and it would appear that alcohol doesn’t do us any good, but this wasn't always the case—our ancestors actually started imbibing because their survival may have depended on it. 

Ten million years ago the primate that would become man, came down from the trees when competition for territory and food became too much. Earth was going through a massive climate change and as the planet cooled, the jungles and forest habitats receded. Scrambling around on the forest floor for food, our forefathers would have come across fallen fruit, often rotting, but it provided sustenance. It was a second rate menu, likely to have been overlooked with the bounty hanging above. But when fights were breaking out in the branches and starvation was becoming a serious problem, that fruit did its job. Fallen fruit contains ethanol, the type of alcohol derived from fermented fruit and grain. Our ancestors had always been able to process some types of alcohol, such as those that occur naturally in plants like geraniol, but not ethanol—and it had a nasty side effect. Ethanol got man’s great, great, great, great, great grandfather drunk. 

“As you can imagine being inebriated in a jungle with predators all around, climbing on branches at night is not a great adaptive strategy.” Carrigan says.

So an enzyme in our stomach, similar to the one known as ADH1 in the liver that can process the alcohol already present in our ancestors' diet, mutated. This mutation enabled their primitive tummies and livers to cope with the new food source. The mutated enzyme is known as ADH4, and it specifically increased our ancestors’ ability to process ethanol and it kept us sober. 

However, this new windfall was no real competition for a nice lush piece of ripe fruit hanging on the vine, so to stop us longing for the good old days up in the trees, Mother Nature made us like it. Carrigan believes that our ancestors’ brains could have changed to reward us for eating fermented fruit.

“The effect of ethanol became something they sought out,” Carrigan states.

It’s possible that low levels of ethanol had a rewarding effect on the brain, so intoxication may not have been their only goal. The joys and miseries of drunkenness didn’t come until 10,000 years ago when early man (a primate further evolved and much closer to us) started farming and storing food in abundance. Only when he learned how to increase the concentration of alcohol did he really get a buzz on. 

“Based on my anecdotal observations,” Carrigan says, “It appears that most people don’t enjoy ethanol at first, it’s sort of like smoking tobacco, you get used to it. I would suggest that because ethanol was linked with nutritional reward that there could have been a reward pathway (in the brain) developed.”

Fermented fruit isn’t that common in the wild and when found it will only yield approximately 1% ethanol. So our forefathers must have been lightweights to get smashed on the food they discovered. Nonetheless, it was then that we got our first taste for it.

The team of scientists Matthew Carrigan leads at the Foundation for Applied Molecular are the first ones to go this far back into our evolutionary history and find that these reward pathways are hardwired into our DNA. From this, the study suggests that alcoholism and other "lifestyle" diseases, such as obesity and diabetes ,have come about because we overload those reward centers.

ADH4 wasn’t designed for modern living. 

“Just because we’re adapted to ethanol doesn’t mean we’ve adapted perfectly. The adaptation was purely for survival…during a time when ethanol was less abundant and concentrated.” 

Those reward centers in our brain were useful when we discovered rarities like sugars, fats, and salts in our ancient habitats; it helped us survive. And the fact that the mutated gene has been "fixed in the population" means it wasn’t a mistake. After all, evolution has a well-known way of ditching her mistakes—“Survival of the fittest.”

The cosmic joke is that ADH4, the enzyme helped us process ethanol so we wouldn’t fall out of our trees and the reward pathway created to encourage consumption, is the reason we overindulge today. Technology has outpaced evolution. It’s because of us that we suffer from alcoholism, obesity, and diabetes. 

Will evolution catch up with our persistent indulgence? Not likely. After all, this isn’t a matter of survival anymore. It’s what might be called "cultural selection" rather than "natural selection." Carrigan has words of warning for those hoping evolution will help us out with our problem drinking:

“Having adapted to alcohol in the past, doesn’t mean we will...become adaptable to the quantities we consume today.”

Increase the amount of ethanol our bodies can process—essentially supercharge the ADH4— and you’re going to increase the amount of the accumulation of acetaldehyde—a toxic byproduct that causes headache, nausea, and general discomfort and leads to the early onset of severe organ damage seen in long-term alcohol abuse. That’s why many Asian populations don’t drink alcohol. "Asian Flush Syndrome" is a gene mutation that leads to the inability to break down alcohol properly. No, Mother Nature has left us to it for the time being. 

In fact, this idea of slowing the effects of alcohol and encouraging the sickness is the idea behind the anti-alcohol drug, Antabuse. A treatment for alcoholism that, in itself, can cause liver damage.

“A negative stimulus,” says Carrigan, ”Not ideal but a solution. Perhaps, like the bark collar on dogs. Bark and a quick lesson is learned but keep barking and it becomes cruel.”

Indeed, for an alcoholic the compulsion to drink is as much mental as it is physical—which shows in the mixed results Antabuse has had in the treatment of alcoholism.

Neville Elder is a regular contributor to The Fix. He's also a photographer and writer. Originally from the UK, he's lived in the unfashionable end of Brooklyn for 13 years. He last wrote about the farce of death penalty drugsrock 'n roll recovery and early morning sober raves.

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British born Neville Elder is a writer,photographer and filmmaker. He's been sober since 2006, lived in New York since 2001 and is in no hurry to move back to a Brexited Britain. He writes the odd murder ballad with his band Thee Shambels and teaches photography at the New York Institute of photography. Find him on Linkedin and Twitter.