100 Million Years of Food (6 page)

Many hypotheses regarding the function of uric acid have been proposed. One suggestion is that uric acid helped our primate ancestors store fat, particularly after eating fruit. It's true that consumption of fructose induces production of uric acid, and uric acid accentuates the fat-accumulating effects of fructose. Our ancestors, when they stumbled on fruiting trees, could gorge until their fat stores were pleasantly plump and then survive for a few weeks until the next bounty of fruit was available. The problem with this theory is that it does not explain why only primates have this peculiar trait of triggering fat storage via uric acid. After all, bears, squirrels, and other mammals store fat without using uric acid as a trigger.

Some researchers argue that the elevated levels of uric acid that accompany gout could have been a survival advantage in ancestral environments that were arid and where food was scarce, because high uric acid levels are associated with increased blood pressure (which is dangerously lowered when salt is scarce) and a greater tendency to deposit fat. Uric acid could have helped to maintain adequate blood pressure in a low-sodium fruit diet and during an interval when Earth's climate was drying out and hence salt loss through sweat could have been a problem.
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However, mammals that thrive in arid environments, like camels and desert mice, seem to do fine without elevated uric acid levels.
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Other mammals also subsist on fruits, but primates are the only animals known to have lost uricase. According to yet another hypothesis, primates are pretty smart creatures, and most of them lack uricase, so therefore uric acid must be responsible for their increased intelligence. While it's true that higher levels of uric acid have been found to protect against brain damage from Alzheimer's, Parkinson's, and multiple sclerosis, high uric acid unfortunately increases the risk of brain stroke and poor brain function.

Those trying to solve the mystery of this trait in human history try hard to recast symptoms of high uric acid as being beneficial in our past. This is a common tendency in evolutionary theorizing; people try to find an evolutionary reason in facts that may actually be by-products of evolution. The cognitive scientist Gary Marcus labeled such evolutionary by-products as “kluges”; some aspects of our bodies, like bad backs, arose because something else had evolved—walking upright, in the case of bad backs—and we humans got stuck with the accidents of history.
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A more realistic proposal for the evolution of uric acid has this character of kluginess. After several million years of not producing vitamin C in fruit-rich rainforest environments, our primate ancestors had no way of reevolving this ability because too many mutations had accumulated in the original vitamin C–synthesizing genes over the long period of disuse; like a car engine too long unused, vitamin C synthesis could no longer fire up. As it happens, uric acid has chemical properties that permit it to function as an antioxidant.
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Therefore, the adoption of uric acid, a by-product of eating fruit and insects, was a possible second-best defense against oxidants. Indeed, higher levels of vitamin C result in lower levels of uric acid and diminished gout, possible evidence that vitamin C and uric acid are partial substitutes for each other.
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Like any evolutionary adaptation, there were drawbacks to uric acid's newfound role as an antioxidant. Exposure to high uric acid levels from overabundant fructose and purine consumption over several years results in insulin resistance, hypertension, and obesity-related disorders. In the ancestral environment, encountering significant quantities of either fructose or purine would have been rare. Today, fructose is plentiful, in the form of soft drinks and sweet, overdomesticated fruits like apples and oranges; purines are also common, found in seafood, meat, lentils, and other foods. A recent study also observed that high uric acid levels are associated with greater excitement-seeking and impulsivity, which the researchers noted may be linked to attention deficit hyperactivity disorder (ADHD).
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Blocking the production of uric acid through drugs like allopurinol alleviates hypertension, at least with adolescents who are not too far down the path of uric acid–mediated damage. However, drugs that reduce uric acid may cause serious side effects, such as immune system reactions resulting in fever, rash, impaired kidney functioning, liver damage, and elevated white blood cell counts.
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At this point, if you were to hand the script over to an imaginative sci-fi writer, he or she might suggest injecting people who suffer from high uric acid levels with uricases from nonprimate animals, or re-creating our ancestral uricase on a computer, synthesizing it in a lab, and injecting it into patients.

Truth is stranger than fiction: Researchers recently combined pig uricase, which is highly effective in breaking down uric acid, with baboon uricase, to lower the risk of immune rejection from human recipients. Although this pig-baboon chimera uricase was effective in reducing uric acid levels, it broke down very quickly in animal tissues and required chemical modification to become stable. Unfortunately, this modification also made the chimera uricase more likely to be rejected by human immune systems. Researchers then used computer programs to reconstruct a uricase that we last possessed
92 million years
ago. The ancient uricase was synthesized in a laboratory using handy
E. coli
bacteria as surrogate mothers for the synthetic enzymes. When injected into healthy rats, the ancestral uricase was found to be a hundred times more stable than the chimera uricase, making it a promising candidate for drug development.
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To put everything into perspective, fruits, like insects, were once an integral part of our evolutionary history and remained a valuable part of traditional diets. Even though meat provides virtually all of the nutrition necessary for survival, at certain times fruit could be crucial to human health, especially when fresh meat and its accompanying vitamin C were unavailable. For example, the Inuit living in Alaska, northern Canada, and Greenland made use of a broad variety of animal foods—seal, whale, walrus, caribou, polar bear, fox, wolf, Arctic hare, waterfowl, fish, mussel, sea urchin, and so on—but the Inuit also harvested a staggering variety of berries. These berries were critical; Inuit who lacked fresh seal meat could develop pustules when the berry crops ominously failed, as occurred in 1904–5 among the Greenland Inuit.
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From being a seasonal snack in traditional settings, fruits in industrialized countries have become sweet, cheap, and holy: Fruits offer urbanites, weary of the associations of meat with disease and cruelty, the opportunity to detox with spiritually unblemished food, a karmic train that inches forward with every four or five bucks forked out for a mega-sized fruit smoothie. Sadly, our ancestors jumped off the tracks leading to Fruit Heaven 16 million years ago, rendering our genes and livers unsuitable for daily jug-loads of fructose. Such a dilemma, however, only arises when we lose sight of cuisine and obsess instead over nutrition. Unlike the here-today-gone-tomorrow wonders of scientific-pop nutrition, traditional cuisines are products of exquisite culture, symphonies of flavors and complementary foods that arose from the mistakes and insights of generations of eaters. People in traditional societies ate fruits in moderate quantities that their bodies could absorb.

Traditional cuisine, in turn, is intimately tied to ecology, the plants and animals that are naturally suited to a given place. Plants and animals can be grown and raised on industrial-sized operations that require a blizzard of chemicals and automation, but people around the world are experimenting with permaculture, the notion of living in an ecologically sustainable manner. Fruits and nuts are important in this movement because they could provide more food than meat could refurbish for a given plot of land. Soon after visiting my friend Bajish in Kerala, I discovered by chance that one of the most visionary and brave pioneers of permaculture lives in the Indian state of Goa, on the western coast of the country, not far from Kerala.

*   *   *

I lean into the turns around Chorao, an island tucked into the hip of the slow-flowing Mandovi River, and sweep past dense fronds on either side of the narrow road, the occasional motorbike or small truck overtaking me. I'm in no rush.

My new friend Hyacinth wrote out the directions last night at her dinner table in her architect's clear script, amid a medley of banana liquor, stir-fried squash, and bitter melon. A crazy kitten kept jumping on the table and kitchen counter, trying to pilfer food. The directions were to a farm owned by a young woman who was a client-turned-friend of Hyacinth. The next morning, after a breakfast of fragrant, warm homemade naan bread, Hyacinth and her friend Jean chaperoned me to a motorcycle rental shop on an oil-blackened side street. The two ladies haggled with the slicked-hair dealer over the rental price. Jean used her status as a high-ranking bureaucrat to vouch for my name, in lieu of leaving my passport. She whispered at me, in a fierce tone, “You can never trust these people, Stephen. Always keep your passport with you.” I was always happy to know someone local; it was better than having insurance. I bade the ladies farewell, fired up the motor, and puttered out to the little highway running along the coastline. On my way out of the city, I stopped at a liquor store to buy a bottle of Indian rosé wine of uncertain quality (trusting the advice of the proprietress), then buzzed across the two-mile causeway, just making it onto a ferry before it set out across the sluggish brown river like a hippopotamus.

I ride across Chorao Island, appreciating the scenes of dense foliage, quiet streets, scattered houses. Soon I regain the mainland. Hyacinth's map is a montage of strong arrows, confident circles, bold lettering. The route is roundabout in comparison to the optimal line that Google Maps conjured, but now I appreciate that Hyacinth wanted me to savor the forests of Chorao Island, a welcome respite from the dusty wide roads and manic flow of trucks and motorbikes on the mainland. Two hours later, I arrive in a small village. My cell phone has no signal, so I ask to borrow a phone from the man behind the counter at a grocery store. I call the number that Hyacinth gave me, trying to reach the owner of the permaculture farm. No answer. I call Hyacinth, who is busy conducting exams for architecture students, and she tries the same number and also gets no answer.

I sit down for a lunch at a restaurant, politely turning down the offer of cutlery, because I'm starting to get the hang of scooping rice and curry with my fingers after patient coaching from Bajish. The curry is blistering hot, but after a week of digging into Indian cuisine, I've lost my extreme sensitivity to chili heat. The owner of the restaurant tries calling the number. No answer. The brother of the owner of the restaurant tries calling as well, but no answer. I call Hyacinth, and she, still in the middle of conducting exams, tries again, with no luck. The brother of the owner of the restaurant takes me to his roadside shop, which sells packaged snacks and drinks. He offers me a finger-length sweet banana. His wife, standing behind the counter of their shop, calls the number. No answer.

Hyacinth calls back on the restaurant owner's phone to tell me the name of the farm, which she learned from a colleague. The restaurant owner gets on my rented motorbike, and I hop on behind. After a few minutes, we take a side road that undulates through thin forests and scraggly fields, reaching a hand-painted sign that announces Foyt's Farm. We ride along a bumpy lane, fumble with a rickety gate, then come to a low red-tiled bungalow. I go around to the back, where a woman and man are sitting on benches and engaged in rapt discussion. Seeing me arrive, the man departs and the woman rises to greet me.

“Oh, you finally got here. I was wondering when you would get here,” she says.

“I'm Stephen. I tried calling your phone…”

“Ah. I must have turned it off.”

Her eyes sparkle and her chin is held high. However, she also carries an embattled air. Clea is the owner of Foyt's Farm, a twelve-acre working farm and learning center, and she never seems to stop moving. On the day that I arrive, she has been busy trying to preserve an insect-infested tree by coating its base with a natural pesticide, finding out what happened to all her chicks (“Perhaps a hawk or mongoose got at them”), and directing the workmen who are installing a sink (“It's crooked!”) in her guesthouse bathroom. Clea has been offering instruction in permaculture and plans to take in more students, but for that to happen she needs to upgrade the bathroom facilities. While my host whirls about her tasks, I take a nap on an inviting outdoor bed, next to a tethered calf that was separated from its mother for medical treatment. Once in a while the calf belts out a loud
mooo
and is answered by its mother on the other side of the house.

The workers finish at five in the afternoon, and Clea comes over to chat with me, looking much more relaxed. Trained at Cambridge as a plant physiologist, she put her Ph.D. on hold to start a permaculture farm in her native country (the weather and food in England didn't suit her). With her father's help, she eventually bought an abandoned farm that she had fallen in love with, a dozen acres deep in the backwoods of Goa. Her self-stated mission is “I want to revolutionize the way that Indians conduct agriculture.”

She and I set off on a tour of the farm. First it's the chicken coop, where twelve hens (sadly without their chicks) are kept at night to protect them from panthers and other nocturnal predators. Clea doesn't raise the chickens for their meat; their job is to pick off termites.

“All the wood structures are safe. Ask all the architects in Goa, they say you can't use wood: ‘All the termites!' We have termite mounds around the farm, but no termites around the house. I think it's because of my chickens.”