Have humans evolved to drink alcohol?

Some people are against drinking alcohol whatsoever; they say that there is no safe level of alcohol for a person to consume, so it is best not to ever drink anything. Here we claim that this stance can’t be correct. Alcohol is a normal byproduct of human cell metabolism. Our cells constantly create a tiny amount of it. On top of that, our gut microbes normally produce a constant, somewhat larger background level of alcohol when they metabolize food in our gut. This alcohol is absorbed into our bloodstream.

And yet on top of that, humans and other hominids evolved to eat fruits, even those that fell on to the ground.

Most of these fruits contain not insignificant amounts of alcohol due to natural fermentation. Here’s an excerpt from one article (see the fuller references, below)

Humans metabolize the ethanol in alcoholic drinks thanks to enzymes called alcohol dehydrogenase 4, or ADH4. Other primates have ADH4 enzymes, but not all can metabolize ethanol. To analyze how ethanol digestion changed over time, Steven Benner, a chemist at the Foundation for Applied Molecular Evolution, built enzymes in the lab that estimated how extinct primates metabolized alcohol.

Benner and his colleagues looked at the DNA stretches responsible for ADH4 in 27 modern primates. Using lemurs, monkeys, apes and humans, they mapped the DNA sequences on an evolutionary family tree for primates going back 60 million years, estimating what genes could have looked like for extinct primate ancestors. Then they resurrected these ancient ADH4 proteins in the lab.

… Ten million years ago, though, a common ancestor of gorillas, chimps and humans emerged with an enzyme that could digest alcohol 50 times more efficiently than earlier incarnations.

…With the availability of fermented fallen fruit on the ground, those forest-dwellers with the ability to digest alcohol would have had an evolutionary leg up. Species like orangutans, which primarily live in trees, didn’t evolve to metabolize ethanol, perhaps because they wouldn’t have run into fermented fruit living above-ground.

from When Did Primates Learn To Metabolize Alcohol?

In sum. humans evolved to safely utilize some level of alcohol on a regular basis.

And if merely having one glass of wine, whiskey, or rum each week had a significant deleterious effect on lifespan then we’d surely see a larger effect on those who drink alcohol daily (even in moderate doses.) Yet even that hasn’t clearly been shown in peer reviewed studies.

We thus can be confident that some level of drinking alcohol per week is safe. That level of course depends on our health, and likely the greatest factor is our genetics.

References

When Did Primates Learn To Metabolize Alcohol? A Chemist Reenacts Drunk History, Popular Science, Shaunacy Ferro, 2/19/13

Were Humans Built to Drink Alcohol? Questions with Patrick McGovern, National Geographic magazine website, 2016/

An evolutionary explanation for why humans crave alcohol, Dina Spector, Business Insider, 2/7/17

Ability to consume alcohol may have shaped primate evolution, Sarah C. P. Williams, ScienceMag.Org 12/1/14

Our Ancestors Were Drinking Alcohol Before They Were Human, BBC Earth, Richa Malhotra, 2/23/17

How Evolution Explains Why Humans Drink and Abuse Alcohol, Robert Dudley, Huff Post, 2/24/14

Alcoholic drinks and the risk of cancer, 2018 World Cancer Research Fund International