Intoxicating: The Science of Alcohol









Alcohol or ethanol has long perplexed our species.  Wherever we look in the ancient or modern world, humans have shown remarkable ingenuity in discovering how to make fermented and distilled beverages and incorporating them into their cultures.  Africa, where Homo sapiens sapiens first emerged some 200,000 years ago, sets the pattern, which is repeated over and over again as humans traveled the world across Asia and Europe and on to the New World.  Africa’s thousands of distinct cultures today are awash in sorghum and millet beers, honey mead, and banana and palm wines, many of which were likely “hangovers” from long ago.  Nearly every aspect of life from birth to death–everyday meals, rites of passage, and major religious festivals–revolve around one or more of these alcoholic beverages.  Similarly, grape wine is central to our western religions, while rice and millet beers held court in ancient China and a fermented cacao beverage was the elite beverage of the Americas.

Despite their popularity among humans, the potential dangers of alcoholic beverages play a sinister leitmotif in human history.  Wine might gladden the heart according to the Psalmist, but it could also sting like an adder.  The great Shang emperors of the later 2nd millennium B.C. are said to have succumbed to too much drink, going crazy and committing suicide.  Prohibition movements inevitably rose up to meet the challenge in various parts of the world from India, where Buddhism stressed meditative techniques for gaining transcendence, to the more recent attempts in 19th-20th America and Europe to stamp out alcohol altogether.  The latter history, which backfired, is amply described in this set of readings.

If alcohol is cast only in a negative light, how does one explain its allure?  To understand this phenomenon, we might begin by pondering why billions of liters of alcohols, including ethanol, form massive clouds in the star-forming regions at the center of our Milky Way.  We might also ask why some of the earliest single-celled life forms on Earth likely nourished themselves by anaerobic fermentation or glycolysis, excreting ethanol and carbon dioxide in the process–similar to the way that natural fermented beverages are made today.

Given the prevalence of alcohol, is it any wonder then that nearly all animals are physiologically adapted to the compound and enticed by it and sugar as well–from the lowly fruit fly, who nourishes its young with it, to birds, and elephants.  Primates are no exception, as elegantly demonstrated by the Malaysian pen-tailed tree shrew, among the earliest primates on the planet going back 55 million years.  This creature feeds principally on fermented palm nectar, drinking the equivalent of nine glasses of grape wine per night for the average human.

Since most modern primates have diets comprised of 75% fruit, and are known to eat and drink as much fermented fruit or drink as possible when given the opportunity, no great leap of imagination is needed to posit that early hominids, our ancestors, were probably already making wines, beers, meads, and mixed fermented beverages from wild fruits, chewed grains and roots, honey, and all manner of herbs and spices culled from their environments.  Thus was ushered in humankind’s first biotechnology, based on empirical observation and with the help of a microscopic yeast, Saccharomyces cerevisiae..

The articles in this collection highlight the modern versions of drinks with very ancient pedigrees, including barley and wheat beers, epitomized by lambics (richly scented and flavored by the combined activity of some 2000 Belgian “wild” microorganisms over a one to three year fermentation period) and grape wine.  Human innovation also eventually led to the discovery of how to make highly carbonated beverages (par exemple, champagne) and to concentrate alcohol by distillation, sometimes with an herbal twist of wormwood, anise and other additives (e.g., absinthe).  As a cautionary note to the reader that science does not stand still, recent findings have shown that absinthe is not a health danger, contrary to the article in this volume, and its production has again been approved by the FDA.

Ancient experimentation in making alcoholic beverages was spurred on by our sensory awareness of alcohol and the plethora of aromatic compounds produced by fermentation; our livers, which efficiently convert the compound into energy using alcohol dehydrogenase, which comprises about 10% of this organ’s metabolic enzymes; and most importantly, the pleasure cascade of neurotransmitters unleashed by alcohol in our brains.  Fermented beverages clearly eased the difficulties of everyday life (e.g., the workers who built the pyramids of ancient Egypt and Mesoamerica were paid in beer), lubricated the social fabric by bringing human groups together, and contributed to a joyful exhilaration in being alive.  Such considerations have been summed up in the “Palaeolithic” or “Drunken Monkey” hypotheses,” which posit that drinking is in our genes, whether for good or evil.

These genes include those related to inebriation, which we share with fruit flies and which carry such fanciful names as barfly, cheapdate and happyhour.  Others are involved in the hormetic response in which low-level exposure to a potentially poisonous compound contributes to beneficial physiological effects.  Non-genetic constraints were also at work: lacking the means to preserve fruit and other natural product in season, ancient humans generally did not have a surfeit of alcoholic beverages as we do today, which poses its own set of problems.

Many of the essays in this volume take a medical approach to alcohol, particularly showing how scientific knowledge of alcohol in relation to human physiology has advanced over the past century.  Much remains to be discovered.  For example, a medical colleague informs me that alcohol’s effects on the brain are so complex and involve so many neurotransmitters that is virtually impossible to isolate them from one another.  Articles appear almost everyday about the positive anti-cancer and cardiovascular benefits (viz., the French Paradox) of drinking alcoholic beverages in moderation, which include a healthy dose of anti-oxidant polyphenols.

Alcoholic beverages were truly the universal medicine of humankind before modern synthetic drugs, because high-sugar resources were widely available and fermentation is a natural process, requiring only minimal human intervention.  Those who drank fermented beverages, rather than raw water, which could be tainted with harmful microorganisms and other parasites, had a longer life expectancy than the usual 20-30 years in antiquity and consequently reproduced more.

Botanical compounds with medicinal properties could also be more easily dissolved in an alcoholic medium, and readily applied to the skin or by drinking.  The world’s ancient pharmacopeias–Chinese, Indian, Egyptian, and Greco-Roman–are dominated by such recipes.

The debate over the pros and cons of alcohol shows little sign of abating.  I would add another confounding ingredient to the mix: is it possible that much of what we consider uniquely human–music, dance, theater, religious story-telling and worship, language, eventually science, even self-consciousness–were spurred on by the consumption of alcoholic beverages during the Palaeolithic period, which comprises some 99% of our largely unknown history?  Our ancestors must have been astounded by the process of fermentation itself, as the liquid mysteriously churned, and was transformed into another substance with psychoactive properties.