Are liquid carbohydrates evolutionarily novel?

 In the debate surrounding the NYC ban on large soft drinks earlier this year, the argument came up that we had to regulate them because liquid calories are evolutionarily novel and inappropriate for our species to consume because we cannot consume them moderately and their metabolism is harmful to our bodies. At the time I had already started reading Patrick McGovern's Uncorking the Past, which looks at human history through the very lens of liquid carbohydrates. 

Not soda, something a bit more delicious and perhaps more enticing. I'm talking about alcoholic drinks. It was in the form of such a drink that I first encountered McGovern's work. I was not pulling in very much money at the time and my indulgence in luxury food and drink primarily came from volunteering at ritzy galas. After one long night, I was delighted to find a vendor had left quite a lot of good beer behind. One of them was Dogfish Head's Midas Touch. With a musky wine-like flavor, it was clear this was not a normal beer.

The idea for the beer came from a golden residue found in a tomb where either the real King Midas or his father was buried around 700 B.C. Archeologist Patrick McGovern had analyzed this residue, teasing out the various ingredients using infrared spectrometry, gas and liquid chromatography and mass spectrometry. Grapes, honey, and barley had were the ingredients of this ancient beverage. Together with the brewers at renowned microbrewery Dogfish Head, McGovern set out to recreate something with these elements for the modern palette. The result was well-received and the first of the Ancient Ales series went to market. 

McGovern is the "Scientific Director of the Biomolecular Archeology Laboratory for Cuisine, Fermented Beverages, and Health at the University of Pennsylvania Museum in Philadelphia." He primarily works at analyzing ancient pottery residues to figure out what exactly our ancestors were imbibing in. And for fun he recreates some of these beverages for modern people to enjoy.

Uncorking the Past says "No containers have yet been recovered from the Palaeolithic period, not even one made from stone. Objects made of wood, grass, leather, and gourds have disintegrated and disappeared." Since it came out, several Paleolithic pottery specimens have been described, mainly from China. Earlier this year, one set of shards was dated to 20,000 years ago. It would not be surprising to me if much earlier pottery is discovered in Africa. Evidence for the earliest food grind stones used to process seeds has been dated to 105,000 years ago. It is possible though that humans in that region were using other containers for liquid such as skins or gourds, but pottery would have been a major advance useful for extracting fat from bones, detoxifying and cooking starches, and creating fermented drinks.

Such drinks would have not been terribly novel even then. As McGovern points out, our evolutionary line is frugivorous in origin, having inhabited warm tropical climates where "as the fruit matured, it would have fermented on the tree, bush, and vine. Fruits with broken skins, oozing liquid, would have been attacked by yeast and the sugars converted into alcohol. Such a fruit slurry can reach an alcohol content of 5 percent or more." Many cases of wild animals getting drunk on ripe fruit have been documented. 

Malaysian tree shrews, subsist mainly on fermented palm nectar that is up to 3.8% alcohol. The researchers concluded:

The pentailed treeshrew is considered a living model for extinct mammals representing the stock from which all extinct and living treeshrews and primates radiated. Therefore, we hypothesize that moderate to high alcohol intake was present early on in the evolution of these closely related lineages.

Wherever primates live, they seem drawn to sugars. Chimpanzees use tools to gather honey in Africa. Hominids there have been adapt at exploiting honey for a very long time, devising elaborate gathering systems to thwart the aggressiveness of native bees. Surveys of foraging tribal peoples like the Hadza and Pygmies have revealed that honey is the food they most prefer. It can also be used to make alcohol:

Many African peoples have been drinking some variation of a fermented honey beverage for a very long time throughout the continent. The strongest versions have been reported from the Rift Valley, where added fruit (e.g., of the sausage tree, Kigellia africana, and tamarind), with additional yeast to spur an extended fermentation, boosted the alcohol concentration. Sub-Saharan Africa is a honey-eater's and mead-drinker's paradise.

It's not just shrews that enjoy palm wine either. Evidence for human exploitation of palm goes back 18,000 years in Africa:

The most important species for making palm wine are the oil palm (Elaeis guineensis), the ron or Palmyra palm (Borassus aethiopum), and the raphia palm (Raphia vinifera), which are concentrated along the humid east and west coasts as well as in the dense jungles of the interior...A healthy tree can produce nine or ten liters a day and about 750 liters over half a year...Within two hours, palm wine ferments to about a 4 percent alcohol content; give it a day, and the alcohol level goes up to 7 or 8 percent

Now back to those food grind stones. The papers that describe them typically talk as if they were used to make the world's crappiest bread out of miserable wild grains. Other grind stones had more obvious uses- they ground pigments for decoration. Why not smear your face with makeup and go out and party? What if the "food" grind stones were really used for making alcoholic drinks? What if people domesticated grains mainly to use in the creation of alcoholic drinks? Seems like more of an incentive than making bitter flat fibrous bread disks. 

It would also explain why the wild relatives of so many grains are mystifying. Looking at teosinte, the wild ancestor of corn, it's kind of baffling why humans would have bothered with the plant at all:

A series of careful DNA studies identified teosinte (genus Tripsacum) as the wild ancestor of maize. This mountain grass grows in the Rio Balsas drainage of southwestern Mexico. One cannot imagine a less inspiring plant to domesticate. The ears of this primitive corn, which are barely three centimeters long and contain only five to twelve kernels, are trapped in a tough casing. Even if you manage to free up the kernels, their nutrient value is essentially nil. 

 The mystery might be solved by quids, chewed and spit out fibrous plant material. This might sound gross, but chewing of place materials and spitting it into a container is an alcohol-making process that has been documented around the world. It seems very likely that the stalks of teosinte were used for this purpose.

The human mouth converts the starch to more easily fermentable sugar using amylyse. Some mouths are better at this than others. Starch consuming peoples typically have a greater amylyse copy numbers, though all humans have a greater copy number than primates like chimpanzees and booboos. "Higher AMY copy numbers and protein levels probably improve the digestion of starchy foods and may buffer against the fitness-reducing effects of intestinal disease." Stephan Guyenet and I have discussed how the copy number thing is interesting because salivary amylyse, even at high copy numbers, contributes very little to digestion of starch relative to pancreatic amylase. What is the increased copy number for salivary amylyse for then? Perhaps for chewing starches like rice and corn to make delicious alcoholic beverages.

Chicha made with saliva remains an important part of the diet of many South American tribes, and a woman's ability to make it is important for her husband's social status. It is rude to refuse it, as this account written up in Salon describes

Patton maintains that the bulk of an Achuar’s daily calories do not come from meat. They come from chicha, a mildly alcoholic, vaguely nutritious, watered-down manioc mash. Achuar men drink up to four gallons a day.Isaac’s wife and mother are in constant motion, serving bowls of chicha to the 10 or so guests. Chicha is the backbone of Achuar society. As with the ankle bone and the knee bone, you feel an unalterable pressure to accept. Chicha is the holy communion, the Manischewitz, the kava-kava of Achuar life. It’s present at every ceremony, every visit, every meal. An Achuar woman’s desirability rests in no small part on her skill at chicha brewing and serving.

Given the amount of calories and nutrients such beverages can provide, it amazes me that many ethnographical and anthropological surveys seem to ignore or downplay their presence, as if they were just mere recreation.

Corn chicha, widely consumed in South America, could not only explain the domestication of teosinte, but it could also account for the fact that isotope studies during the time of corn's domestication don't seem to show people got their protein from corn:

Some very interesting results emerged when human bones from sites throughout the New World were examined. Because maize had been domesticated by about 6ooo B.P., one would have expected to see a specific carbon-isotope composition that reflected the increased consumption of maize, but it was strangely missing. Some scientists have proposed an explanation for this anomaly. Because the analyses measured only the collagen in bone, its main proteinaceous connective tissue, they were biased toward detecting high-protein foods. Solid foods made from maize, including gruel or bread (e.g., tortillas), fit this requirement, but not fermented beverages like maize chicha, largely composed of sugar and water. Consequently, if people between 6ooo and 3000 B.P. were consuming their maize as chicha, very little protein would have been incorporated into the collagen of their bones. The researchers speculated that humans began using maize as a solid food only after its ear had been substantially enlarged by selective breeding, around 3000 B.P. After this point, the carbon isotope compositions of bones dramatically changed.

 Interestingly, going further north, the Native Americans there didn't seem to have any alcoholic beverages, or if they did, they had been spread from the South. Charle's Mann's 1491 discusses the hypothesis that the North and Southern Native Peoples were peopled differently, South America being populated by a sea-faring coastal society, rather than from Beringia up North. McGovern describes the culture of the coastal peoples, who consumed a tantalizing array of berries, fish, mollusks, wild tubers, mastodon meat and fat (they processed enough fat that it congealed on the floor, which my sister's roommate reenacted recently by pouring some bacon grease directly down the drain), bulrushes, and seaweed. It is theorized that the cold snap of the Younger Dryas around 13,000 BC may have forced them to rely more and more on underground tubers, spurring on the domestication of the potato.

However, the Siberians, like the North Americans, do not have alcoholic beverages (that we know of at least), relying on other resources for a buzz:

In place of any alcoholic beverage, the Siberian peoples engaged in shamanistic practices based on the hallucinogenic fly agaric mushroom (Amanita muscaria). When European explorers finally braved the frigid tundra of Siberia, beginning in the mid-seventeenth century, they recorded how the shaman often dressed in a deer costume with antlers, like the Palaeolithic creature depicted in Les Trois Freres cave (see chapter i). After consuming the mushroom, he would beat on a large drum, whose monotonous repetition reinforced the effects of the active hallucinogenic compounds (ibotenic acid and muscimole) and took him into the ancestral dreamtime.


Northern peoples in the Americas also smoked tobacco. Meanwhile, people in the Southern parts North America certainly did imbibe in alcohol. The Pima who are so infamous in nutritional circles consumed a sweet cactus wine. The health effects of another regional beverage, Pulque, which is made by fermenting agave sap, have been explored a bit. It was found that among highland tribes that consume it, it accounts for much of the iron and Vitamin C consumption in pregnant women. Pregnant women who consume too much or none are more likely to have low-BMI and reduced mental performance infants. Consumption of pulque might also increase the bioavailability of vitamins in other traditional foods.

The use of agave in fermented beverages should be considered when looking at data from that region that suggests a high fiber consumption from these plants, particularly given the presence of quids and the fact that these fermented beverages could enhance digestion of fructooligosaccharides in these plants. I've seen such papers conclude that this means that humans in these regions ate absurd amounts of fiber and we should emulate them. What is more likely: that anatomically moderns humans were eating 255 grams of fiber a day from plants like agave, well above what any known living culture consumes, or that they were making something a bit like tequila? 

It is possible that such drinks have been under emphasized because of very real issues of alcoholism that plague many modern indigenous peoples. However, most of these traditional alcoholic beverages are not like the modern alcohol that is abused. Indigenous beverages are typically 3-6% alcohol, seasonal and contain many nutrients and phytochemicals, which are biologically active plant chemicals. McGovern's lab has been working on exploring the medicinal properties of many of these phytochemicals. 

McGovern describes how many of the early beverages in the Middle East, ancestors of our modern wines and beers, contained potent medicinals. Early grape wines, for example, often contained tree resins:

Tree resins have a long and noble history of use by humans, extending back into Palaeolithic times. They could be used as glues and were perhaps even chewed to give pain relief, as suggested by lumps of birch resin with tooth marks that were found in a Neolithic Swiss lake dwelling...Resinated wines were greatly appreciated in antiquity, as we have come to see in analyzing wines from all over the Middle East, extending from the Neolithic down to the Byzantine period. Although some wine drinkers today turn up their noses at a resinated wine, now made only in Greece as retsina, the technique is analogous to ageing in oak. The result can actually be quite appealing: the Gaia Estate's Ritinitis has a mildly citrusy flavor, achieved by adding a very slight touch of Aleppo pine resin to a Greek grape variety. Even the Romans added resins such as pine, cedar, terebinth (known as the "queen of resins"), frankincense, and myrrh to all their wine except extremely fine vintages. According to Pliny the Elder, who devoted a good part of book 14 of his Natural History to resinated wines, myrrh-laced wine was considered the best and most expensive.

It is a powerful reminder to consider ancient diets holistically, that things were not just consumed for their nutritive value, but for recreational, medicinal, and religious purposes. And possibly some of these substances were "unwise" traditions and may account for some of the diseases found in mummies and skeletal remains if people drank too much or adulterated their beverages with carcinogens and other poisons. Even today, adaptation to alcohol seems uneven and imperfect in humans, as many Asians who experience Alcohol Flush Reaction will attest. Distilled high-alcohol spirits are also very much an evolutionary novelty. As someone with alcoholism running in the family, I very much understand that consumption of these kinds of alcohol can be difficult for certain people to moderate with terrible, even deadly consequences.

I think renewed study and emphasis on fermented alcoholic beverages in human evolution will provide much insight into human adaptations to food and the development of domesticated crops. Even with the knowledge we have now, I think it's wholly inappropriate to describe liquid carbohydrates as evolutionarily novel. Soda is novel in that it is a liquid carbohydrate devoid of any of the nutrients or phytochemicals in indigenous beverages, but mainly we need to look to modern science and biochemistry to tell us what effect soda has on the body and mind. 

 It's also fascinating to see some of these ancient beverages recreated and revived. I've since tasted several of McGovern's collaborations with Dogfish Head, such as Chateau Jiahu, which is made of rice, honey, and fruit recipe gleaned from 9000 year old Chinese pottery. I've also enjoyed some of the more modern spit-free chicha at several Peruvian restaurants and being a lightweight, I appreciate that it's pretty low in alcohol and also very tasty. There has also been renewed interest in home brewing ancient herbal ales. You can do it yourself with the book Sacred & Herbal Healing Beers. There are also some herbal beers on the market. I've enjoyed William Brother's spruce, seaweed, and heather beers. Unfortunately, none of these beers are gluten-free, which is slightly disappointing since the original Jiahu pottery probably did not contain barley. 

I enjoyed Uncorking the Past, but it does read a bit like a textbook at times, which is why it took me so long to get through it. I'm looking forward to enjoying more of his brews though. Dogfish Head is even tried making Chicha the old fashioned way, though it didn't exactly work out, since it was more labor intensive than they expected.