Zoobiquity

  It wasn’t that long ago that a serious human intestinal medical condition was unexpectedly found to have an infectious component. For decades, gastric ulcers were believed to occur as a result of our stressed lives and overly reactive psyches. You got them, the medical wisdom went, if you were anxious and couldn’t resist greasy, spicy foods. In 2005, the Australians Barry Marshall and J. Robin Warren, a physician and a pathologist, won the Nobel Prize in Medicine for busting that myth. They identified the cause of many ulcers as Helicobacter pylori, a contagious bacterium easily treated with a dose of antibiotics. The road to the Nobel was long, however. For years Marshall and Warren had to endure criticism, rejection, and scorn. But now the microbiome is being examined for organisms that may be responsible for irritable bowel syndrome and Crohn’s disease. Maybe obesity should be next.

  But the research on infectious causes of metabolic syndromes is still at the stage where nutrition scientists and doctors dismiss it—or at least don’t seem quite ready to hear it. Marden published his research in a top academic journal, the Proceedings of the National Academy of Sciences, and wrote an opinion piece for a human diabetes journal. Yet he told me there “really wasn’t much response. I don’t think the medical community was swayed by our results or super eager to hear about it. It’s been pretty much a ‘so what?’ from the medical community.”

  Whether infection will ultimately be proven to play a part in human obesity is still hard to say. However, a cross-disciplinary, zoobiquitous approach—one that connects the knowledge of a dragonfly expert in an agricultural sciences biology department with researchers looking at human obesity—may spark innovative hypotheses and a broadened view of this major health threat. We live in a world teeming with organisms in us, on us, and around us. Our defenses against them drive many of our diseases. It’s critically important that researchers charged with understanding and containing obesity’s dangerous growth remain open to ecological factors, including lightness, darkness, seasonal shifts, and, yes, even infectious organisms. As Marden put it when his paper came out in 2006, “Metabolic disease isn’t some strange thing having just to do with humans. Animals in general suffer from these symptoms … [and] it would be irresponsible for us not to point out these possibilities.”

  To repeat: “Obesity is a disease of the environment.” And while Big Gulps and Segways play a primary role, so, too, do these much larger and much smaller forces. An expanded, environmental approach to weight has already cured two obese patients from the Chicago area—those two obese grizzly bears at the Brookfield Zoo.

  Whether it was circadian rhythms, imbalanced microbiomes, seasonally confused intestines, an infectious parasite, or just access to too much food that caused Axhi and Jim to pack on the pounds over the years is hard to say. But their pattern of fattening before Watts changed what, when, where, how, and how much they ate resembles our own.

  Watts had decided to make a massive change that was both innovative and as old as eating itself. She would approximate the yearly rhythms of a wild diet. In other words, she would let the seasons and the bears’ bodies lead the way.

  She started with what they ate. For years, their food had been abundant, readily available, and largely unchanging throughout the year. It included processed dog food, bread from a local bakery, supermarket apples and oranges, and ground beef. Gradually, Watts challenged the bears’ taste buds. She swapped out a serving of lettuce and introduced kale. She traded mango for apple. Then spinach, celery, peppers, and tomatoes subbed in for sweet potatoes and oranges. Although this produce wasn’t exactly identical to what they’d find growing on the banks of an Alaskan river, in terms of nutrient range, variety, and seasonality, it was an improvement.

  Soon, when the keepers showed up with a meal, the bears were as enthusiastic as human foodies sniffing out the exotic offerings at a new gastropub. Watts also added whole prey like fish, rats, and rabbits, and timed their appearance on the menu with when those foods would be found in the wild. She also ordered boxes of wax worms, which she dumped in the bears’ foraging pile—a big, peaty dirt mound—and let them rummage and eat to their hearts’ content. With each of these dietary introductions the bears consumed not only new sources of protein and vitamins at seasonally appropriate times of the year, but whatever new and varied microorganisms happened to be making those food items their home. Although she notes this wasn’t at first intentional, Watts was following her own motto: “feeding the bugs” in their GI tracts.

  Watts also decided to allow the bears to enter a more seasonally appropriate winter torpor. It wasn’t a full hibernation (which many bears in the wild don’t do anyway). But it was a big change for Axhi and Jim. For the previous decade, the bears had been awakened every day throughout winter for feeding. Sometimes the keepers had to rouse them by shouting or making loud clanging noises. Watts instructed that the bears be allowed to sleep through the winter months. And she ordered that, if they woke, they not be presented with food around the clock but be given “one shot” at a small amount before it was removed. On the surface, this plan would seem to work in favor of weight loss because it reduced the number of overall calories the bears consumed. But its efficacy may have been deeper than that. Sleep and metabolism are interconnected, and the longer periods of fasting may have signaled other physiologic changes to the bears’ bodies, such as intestinal lengthening or shortening.

  Finally, the bears were moved to a larger home. In this new environment, their food could be presented to them in ways that were “inconvenient,” causing them to mimic the foraging and hunting they’d do in the wild and expend more energy getting at a meal.

  Yet even with all these changes, Watts was not able to wholly re-create the bears’ natural diet. Just as it would be almost impossible for us to eat like our ancestors did even a hundred or a thousand years ago, it’s unfeasible for zoos to duplicate a wild diet for each animal. The fruit zookeepers buy from grocers and wholesalers is a far cry from the fruit a wild animal eats.c There are no naturally occurring banana plantations in the Canadian Rockies. No orange groves. No wild watermelon vines or mango trees. And even if Watts could have gotten fruit with the same characteristics in the exact proportions to what is found in the wild, the microorganisms on that washed, boxed, refrigerated, and shipped fruit would be completely different from what the animal would be eating in a natural setting.

  Fortunately, Watts understood that the fantasy of creating “the perfect wild diet” was just that—a fantasy. She did the best that she could under the circumstances. And it turned out that adjusting the bears’ diets in ways that were simply informed by knowledge of their natural ecology was enough. They lost weight. They seemed to feel better and have more energy. In short, they were healthier.

  Watts’s success carries lessons we can apply to our own lives, whether we want to address the global obesity epidemic or a personal weight-loss effort. Researchers and doctors ought to consider the environment’s cyclical periods of abundance and scarcity as well as the seasons’ effect on our food-absorbing intestines. We must take seriously the complex universe of the microbiome and the metabolic consequences of infection. We need to think about global forces like day length and light cycles.

  Modern, affluent humans have created a continuous eating cycle, a kind of “uniseason.” I’ve started calling this blissful, bountiful, yet static and superfattening environment the “eternal harvest.” Sugar is abundant, whether in our processed foods or in beautiful whole fruits that have had their inconvenient seeds bred out of them and that “unzip” from easy-to-peel skins and pop open into ready-to-eat segments. Protein and fat are everywhere available—in eternal harvest the prey never grows up and learns to run away or fight us off. Our food is stripped of microbes, and we remove more while scrubbing off dirt and pesticides. Because we control it, the temperature is always a perfect seventy-four degrees. Because we’re in charge, we can safely dine at tables aglow in light long after the sun goes down. All year round, our days are lovel
y and long; our nights are short.

  As animals, we find eternal harvest an extremely comfortable place to be. But unless we want to remain in this state of continual fattening, with its accompanying metabolic diseases, we will have to pry ourselves out of this delicious ease.

  *At Bertelsen’s zoo, as at many other institutions that carcass-feed, the carnivores are usually fasted for a few days after a big meal, mimicking the more naturalistic gorge-and-fast patterns of some wild animals. Together with scientists from the pet food corporation Hill’s, Joanne Altman of Washburn University in Topeka, Kansas, studied five captive African lions at the Topeka Zoo. The cats were switched from daily feedings to just three meals per week. The gorge-and-fast regimen, they found, improved the cats’ digestion and metabolism and decreased the amount they ate. The animals showed fewer restless pacing behaviors.

  †Of course, the biggest factor in the amount of sunlight any creature receives is where it finds itself on the globe. Latitude does seem to correlate with metabolism trends in mammals as well as sugar production in plants. (In general, the farther from the equator, the lower the sugar concentration in blood or berries.) Whether the effects are direct (from exposure to sunlight or other physics forces like electromagnetism or gravity) or evolutionary (adaptations over generations to available foods in any given area) remains a question for more research. But geographic effects on human weight have been all but completely ignored.

  ‡For entertaining and illuminating reporting on the microbiome in particular and microbiology in general, see the work of Carl Zimmer, a New York Times science writer and the author of, among many other books, Microcosm and A Planet of Viruses.

  §Entrepreneurial-minded thin people take note: the teeming bacterial clusters inches beneath your belly button may be fermenting a billion-dollar opportunity. If the dominant species of bacteria in our guts helps determine our BMIs, perhaps a fecal or oral infusion of Firmicutes or Bacteroidetes in certain proportions would speed us to our body-image goals. There may come a day when, instead of logging calories, we could lose weight by purchasing desirable gut flora from the thin (but not squeamish) bacterially blessed.

  ‖In human medicine, so-called fecal therapy is a breakthrough treatment for stubborn and sometimes life-threatening diarrhea and other gastrointestinal problems arising from infections with organisms such as C. difficile. Feces are acquired from an individual (frequently a spouse) with normal gut flora, mixed into a slurry in a kitchen blender, and placed on the tip of a specialized endoscope for insertion into the small intestine of the ailing recipient. You may be wrinkling your nose, but it’s an extremely effective and low-cost solution to restore human health. And farm veterinarians have been doing it for decades. Bug-rich biliary gastric juice is extracted through a fistula created in a side surface of a healthy donor cow. This “liquid gold” (not to be confused with the urinary liquid gold used by stallion breeders) is extracted and then transferred into other animals to normalize their gastrointestinal flora. Zoo veterinarians routinely use fecal therapy to normalize their patients’ digestive tracts after rounds of antibiotics. It’s especially effective for mother-infant pairs.

  aDragonfly blood is called hemolymph, and its main carbohydrate is trehalose; Marden calls it blood sugar.

  bMetabolic syndrome increases a patient’s risk for heart disease and stroke. Also known as insulin-resistance syndrome, it is diagnosed when triglycerides, blood pressure, or glucose are too high or when a patient’s “good” cholesterol (HDL) is too low. An apple-shaped body is associated with metabolic syndrome.

  cEverything we recognize as wholesome fruit is the product of careful crafting and managed evolution—begun with the earliest human agriculturalists and “improved” over the millennia, intensively over the last few decades. The fruit we find in the supermarket today has been cultivated for human tastes (and transportation convenience). Puffed up with extra water and soaring sugar content, commercially grown fruit also has less fiber than fruit found in the wild or in the ancient past.

  EIGHT

  Grooming Gone Wild

  Pain, Pleasure, and the Origins of Self-Injury

  Name a medical complaint or affliction, and you’ll find an online support group for it. These sites allow people to swap stories, share remedies, and feel less alone. The posts are often heartbreaking. Recently, I was scrolling through some online forums. The threads practically wailed with misery: “I am so worried,” “This is tearing me apart,” “I am afraid he isn’t going to stop,” “I am at wits’ end,” “He’s had this problem for years,” “Can someone please help me?,” “I feel so terrible—like I am a horrible mommy.”

  The sites were not about human patients. They were about pet birds with the surprisingly common problem known as “feather-picking disorder.” While the individual stories varied, the overall theme was the same. Birds with names like Juliet, Zeke, Jubilee, and Ms. Earl were all perfectly healthy, until one day their owners discovered a pile of colorful plumage at the bottom of the cage … and a bald patch on their pet’s shoulder or chest or tail. The birds were plucking out their feathers, one by one, and sometimes pecking the underlying skin until it bled. Veterinary exams ruled out physical causes of irritation, like mites or infections. The owners installed humidifiers, smoothed aloe vera on the stubbled skin, and invested in higher-quality birdseed. Still the picking continued. One despairing owner of a self-plucking Quaker parrot wrote, “Lately she has been pulling and letting out that little scream like they do when you touch the wrong pinfeather, then she goes right on and does it again, so now she’s plucking even if it HURTS … and I have seen several small spots of blood on her crop and under her wings.”

  As a human physician and psychiatrist who’s never in my life owned a bird, I nonetheless recognized these symptoms: an inexplicable change in behavior, deliberate actions that caused bodily pain and disfigurement, and confusion and distress in loved ones. They brought to mind a patient I saw a couple of years ago, a twenty-five-year-old woman who presented with heart palpitations. Traversing her inner left forearm was a series of expertly cut incisions, ones that in other circumstances might have been the handiwork of one of my surgical colleagues. Thought had clearly gone into sterilization, cleanliness, and how the cuts would heal. But no doctor had been present when they were made. Instead, my patient had taken a razor in her right hand and sliced into her own skin. She was a “cutter.”

  Cutting is probably our era’s most iconic form of human self-mutilation, seemingly tailor-made for suburban-parent hand-wringing and tabloid ogling. Its name says it all, but in case you don’t know: it means taking something sharp—maybe a razor blade, scissors, broken glass, or a safety pin—and purposely slicing it across your skin to draw blood and create wounds. Usually, cutters target parts of their bodies that can be covered up with clothing to hide the evidence—say, their inner arms, thighs, or stomachs. Some do it impulsively, with whatever tool is at hand; others are more ritualistic about it. They might cut at the same time and in the same place every day. Or they create “kits” that hold their favorite cutting implement, along with gauze, Band-Aids, and alcohol wipes for mopping up afterward. As you can imagine, cutters—especially those who do it for many years—develop scars, often parallel lines like crimson ladder rungs up and down their favorite cutting site.

  Psychiatrists call cutters “self-injurers” to include the whole range of inventive ways people dream up to hurt themselves. Some burn themselves on purpose with cigarettes, lighters, or tea kettles. Others bruise their skin by banging, punching, or pinching themselves. Those with trichotillomania rub and rip out hair on their heads, faces, limbs, and genitals. Some are swallowers, ingesting objects such as pencils, buttons, shoelaces, or silverware. We see this particular method a lot in prisons.

  You may think self-injury occurs only in edgy subcultures or the seriously mentally ill. But my psychiatrist colleagues say it’s sweeping through the general population. Therapists and school guidance couns
elors confirm this.*

  Self-injury has gained an unintended endorsement by public figures. I, for one, was shocked by Princess Diana’s disclosure to the BBC in 1995 that she cut herself with a lemon peeler and a razor blade. She also engaged in non-blade-related self-injury, including hurling herself into a glass cabinet and throwing herself down a flight of stairs. While Angelina Jolie has restyled herself as a supermom and human rights crusader, she joined such other celebrities as Christina Ricci, Johnny Depp, and Colin Farrell in telling the world about a self-injuring past; their tools included knives, soda can pop-tops, broken glass, cigarettes, lighters, and their own fingers. Cutting’s edgy street cred includes feature appearances in angsty teen films like Thirteen and Girl, Interrupted. And cutting even made a comic turn in the movie Secretary, with Maggie Gyllenhaal and James Spader embarking on what is perhaps the most happy-go-lucky sadomasochistic love story ever told.

  But confronted by my cutter patient’s razor-notched arms, I was still confused. She was a thoughtful, intelligent adult woman with a respectable job, very much like the Maggie Gyllenhaal character in Secretary. Why would she cut herself on purpose—something a doctor would consider doing only with anesthetic and strict protocols? So although she was in my office for a heart consult, I asked her. She answered matter-of-factly, “My shrink says I’m trying to kill myself. But I’m not. If I wanted to die, I would. Cutting just makes me feel better. It relieves me.”

  Her answer jibed with what other cutters say. A twenty-two-year-old woman writing on a Cornell University website put it this way: “I began cutting my arms at the age of 12.… I think I could best describe the feeling I get as total bliss. It relaxes me.”

  Bliss? Relaxation? Relief? It “feels good”? Even after years of psychiatry training and two decades around a hospital, I still think this sounds incredible. But cutters and their therapists say it’s true. And they confirm that most self-injurers are not suicidal, though sometimes a cutter will go too deep with the blade and require medical attention.†