Jon Shireman/Getty Images

The office of allergist Paris Mansmann, MD, sits on a grassy slope overlooking the Royal River, a wide waterway that originates in inland Maine and winds down across farmland and under train tracks until it hits the coastal town of Yarmouth, where it sloshes into the Atlantic Ocean. When I first came to Mansmann in February 2011, the river was covered with ice, and bare trees stood silver sentry on its shores. I was 36. I'd been sick for three and a half years.

During that time, when I wasn't working as a writer and theater director or being a wife and mother, I visited doctors and had tests. I told few friends or members of my extended family how ill I was, because I didn't have any way to explain what was wrong. I had no diagnosis, just a collection of weird symptoms: tight, achy pain that radiated through my body and caused me to hobble around (my ankles, I'd joke to my husband, Dan, felt like they'd been "Kathy Batesed," à la the movie Misery); burning rashes that splashed across my cheeks and around my mouth like pizza sauce; exhaustion; headaches; hands that froze into claws while I slept and hurt to uncurl in the morning; a constant head cold; nausea; and, on top of all that, severe insomnia—my body just could not, would not, turn off and rest. I visited every doctor who'd see me and tried everything they threw at me: antidepressants; painkillers; elimination diets (including a long eight months when I went without any of the major allergens, such as gluten, nuts, dairy, soy, and nightshades); herbal supplements; iodine pills; steroid shots; hormone treatments; Chinese teas; acupuncture; energy healing; a meditation class—you name it, I did it. Nothing worked. After I maxed out the available rheumatologists, endocrinologists, nutritionists, gastroenterologists, Lyme disease specialists, acupuncturists, and alternative-medicine practitioners in the Portland metropolitan area, I was sent to neurologists in Boston. All of my tests came back normal.

In late 2010, after a long and unhappy antibiotic treatment for Lyme disease, my newest GP (who's still my doctor today), Chuck de Sieyes, MD, announced that he was referring me to Mansmann: "Because I have no idea what's going on with you, and he's one of the smartest guys around. And frankly, I've had it!"

Mansmann had moved to Yarmouth with his wife and kids to be close to his parents, who'd retired in Maine. A third-generation allergist, he worked in his father's allergy clinic, at Jefferson Medical College in Philadelphia, during high school. While in college at Saint Joseph's University, also in Philadelphia, he helped his dad develop two asthma drugs. Later, he headed an allergy and immunology clinic at a West Virginia hospital for 10 years.

Mansmann has a helmet of thick, graying hair and an intensely serious air. After escorting me into an exam room, he sat down across from me and promptly pushed aside my thick medical file. He'd read through it all, he said, but he wanted to hear the story from me. He listened patiently, asking questions every so often: When did my rashes flare? Was the pain an ache in my muscles, or did it feel deeper? Was I worse after I slept or at the end of the day? He seemed, as we spoke, to have all the time in the world. Then, with no pyrotechnics, he offered his theory: "I think it's possible you've developed a reaction to genetically modified corn."

Genetically modified corn? Everyone's heard of GMO corn, but I realized I didn't know what it actually was. Mansmann explained that starting in the mid-1980s, the biotechnology giant Monsanto began to genetically alter corn to withstand its herbicide Roundup—the goal being to eradicate weeds but not crops—as well as to resist a pest called the corn borer. These small changes in the DNA of the corn are expressed by the plant as proteins. It's those proteins, Mansmann believes, that can act as allergens, provoking a multisystemic disorder marked by the overproduction of a type of white blood cell called an eosinophil.

He swabbed inside my nose with a Q-tip, then placed the results under a microscope. "Take a look," Mansmann said. "See all those pink cells? Those are eosinophils." My nose, it seemed, was chock-full of them. When the immune system is working properly, eosinophils swarm certain invading substances, be they parasites or viruses, and work to eliminate them. Sometimes, however, an allergenic protein may prompt the immune system to release eosinophils. Then, it's as if a faucet gets turned on but can't be turned off—eosinophils just keep coming. Eventually they begin to leave the bloodstream and may infiltrate and damage the GI tract, esophagus, mucous membranes, lungs, the fascial system (the layer of connective tissue that surrounds the muscles, blood vessels, and nerves), and the skin—hence, the avalanche of symptoms. (Some allergists say that the best way to test for a true eosinophilic disorder is to look for the cells in the esophagus and GI tract with an endoscopy. But Mansmann thinks that once you have a preponderance of them in your nasal mucus, they're likely to be elsewhere.)

Mansmann's advice was to strip all corn, even that marked organic, from my diet. "It's almost impossible to find a corn source in the United States that doesn't have the [protein] in it," he said. The U.S. government started approving GMO corn and soybeans for sale in the mid-1990s, and today, 88 percent of corn, and 93 percent of soybeans, are the transgenic varieties. Moreover, Mansmann and others contend that due to cross-pollination via winds, birds, and bees, there's no such thing anymore as a GMO-free corn crop. He estimated that it would take from two to four months of living without corn for the eosinophils to cycle out of my body, and almost a year before I'd feel entirely like myself.

Getty Images

While I quickly discovered that blaming GMO foods for any kind of health problem is controversial in the medical and biotech worlds, what's beyond debate is the increase in the incidence of autoimmune disorders such as type 1 diabetes, lupus, and celiac disease, as well as of allergies. As for the latter, the National Health Interview Survey found, for instance, that since 1999, the number of children with food allergies has jumped by 50 percent, and those with skin allergies by 69 percent (and the increase isn't merely a by-product of fuller reporting by parents, experts say).

Allergenic eosinophilic disorders, however, aren't counted in that data. They were first identified about 20 years ago, according to a pioneer in the field, Marc Rothenberg, MD, PhD, a professor at University of Cincinnati medical school and director of an affiliated center for eosinophilic disorders. "We're in the midst of an allergy and autoimmune epidemic," Rothenberg told me on the phone, "and the environment is the black box." Mansmann's GMO theory was "interesting," he went on, before quickly adding that "no one in conventional medicine will have the data" to prove it.

Back in 2011, though, I was desperate enough that I was willing to try the diet Mansmann recommended. After all, how hard could it be to give up corn? The answer was: way harder than I imagined. Corn was my Waldo, popping up everywhere: in tea bags, juice, and cheese culture; it lined my "to go" coffee cups and plastic bags of frozen vegetables; it coated my store-bought apples and was on the bottom of restaurant pizza—almost everything my family used, no matter how piously natural and organic, had corn in it. It came under the guise of dozens of names like "xanthan gum," "natural flavors," "free-flowing agents," "vitamin E," "ascorbic acid," "citric acid," and "cellulose," to name a few. Almost daily, I'd find a new culprit. "Damn, this toothpaste is full of corn!" Then: "Wait, our dish soap is made from corn!" Or: "Oh my God, iodized salt has dextrose in it!"

Not to mention the corn that is fed to animals whose meat and eggs I ate, whose milk I drank. I had to restrict my diet, Mansmann said, to vegetables, grains other than corn, grass-fed beef and dairy, wild fish, and game (if I was game). My husband and I threw ourselves into the corn-free diet with gusto: We began baking all our bread, we learned how to make our own flour tortillas and sweet treats like muffins and cakes. By luck, we met an intrepid farmer raising corn-free chickens (harder than you might guess, because chickens have literally been bred to get fat fast on corn). We eschewed anything premade and began gathering foods from local sources we could trust. I stopped taking every medicine or supplement with corn in it (which was most of them). Wherever I went, I took my own stainless-steel coffee cup.

The first thing I noticed was that my skin rashes began to dissipate. Then, slowly, my body stopped aching, and I could walk or even jog easily, for the first time in years. I started to have more energy, and I slept better at night. The head cold went away—poof—and I wasn't going through a box of tissues a day. My hands became less stiff. I realized, in retrospect, that my frozen hands had been the hardest symptom to tolerate: I could barely button my son's small shirts or apply a Band-Aid, which made me feel useless as a mother. Almost four months later, in late May, I felt pretty much like my old self. I was so startled by my physical well-being that I didn't know how to enjoy it. Each night I'd go to bed preparing myself for the possibility that I might wake up sick again the next morning. Could GMO corn really be my problem? Could this blessed state really last? I couldn't let go; I had to know more. I decided to visit Rothenberg and his team of researchers endeavoring to crack open the black box.

When I landed in Cincinnati, it was sticky and eerily airless, though it was early June and well after midnight. I couldn't help but think about how one doctor had told me that the Ohio River Valley is basically a bowl that collects pollen and pesticide sprays from across the Midwest, creating a special kind of allergic hell.

The next morning, I made my way to Rothenberg's lab. Despite wearing sneakers and khakis and sporting a "Hey, hey, we're the Monkees" hairdo, Rothenberg exuded a scientist–rock star vibe—he moves through the world with importance. Over the next couple of days, he told me, I'd meet people whose views represented a microcosm of the worldwide debate over the safety of GMOs.

First up: Karl von Tiehl, a young, cherub-faced clinician and assistant professor in the medical school (he has since moved to Los Angeles to go into private practice). Our interview had barely begun when he informed me that my interest in the impact of big agriculture on the food supply was a preoccupation of his as well. He told me that, for the very worst patients who come to Cincinnati (those whose GI tracts and esophagi have been so damaged by eosinophils that their lives are severely compromised), the team has found that if they "give them a medical food that's been so chopped and sliced and diced that there are no proteins in it, that it's just amino acids, simple sugars, and small fats and stuff—there's nothing their immune system can react to—95 percent of the time, the disease goes away as long as they stay on that simple, horrible smelling, tasting formula." Von Tiehl doesn't know if GMO crops are the culprit, but, he says, "you're eating what somebody in some office has decided is good for you rather than what your grandma would have told you is good for you. There's something scary there."

A short walk down the hall, his colleague Amal Assa'ad, MD, also a professor at the medical school, dismissed anxiety over GMOs' safety as almost magical thinking. "What's wrong with chemicals?" she asked. "We're so afraid of chemicals because they are man-made, right? A lot of chemicals have helped us—a lot of medications are chemicals." If anything, GMO foods have been a boon to mankind, Assa'ad said. GMO seeds "produce better crops that have increased production, that are resistant to pesticides—crops that can feed the rest of the world."

She echoed the federal government's position—given voice through the regulatory policies of the USDA, the Food and Drug Administration, and the Environmental Protection Agency—that there is nothing inherently dangerous about inserting the gene of one species into that of another, since the end product is essentially identical with that grown from regular seeds. This is also, perhaps needless to say, the biotech industry's stance. "There are several hundred studies that contribute to a huge body of evidence that GM crops…are as safe as their conventional counterparts," says Monsanto spokesman Thomas Helscher.

To experiment with a new GMO food in this country, a developer must first get a permit from the USDA to conduct field trials (literally, trials in open fields), following guidelines largely intended to prevent GMO crops from mixing with conventional ones. In addition, according to Helscher, biotech firms like Monsanto are required to compile a document that compares the biology of the modified plant to the unmodified one, determining, for example, if there is a "statistically significant difference" in the levels of nutrients such as carbs and fats between the two plants, or, if new proteins are introduced, whether they're included in the database of known allergens. If nothing goes obviously wrong, the crop is free to go to market.

It all sounds fine, until you dig a bit deeper, critics of this process say. For one thing, they question the objectivity of the allergen database because it's compiled at the University of Nebraska–Lincoln, whose facilities are funded by the six major biotech companies: Monsanto, Syngenta, Dow, Dupont Pioneer, Bayer, and BASF. Indeed, no GMO proteins are on the list, but that's for lack of "sufficient evidence" to put them there, says Richard Goodman, PhD, a UNL research professor and former Monsanto employee. He does add, however, that much of the existing data regarding the allergenic potential of GMO foods simply examines them for amino acid sequences similar to those in known allergens—like peanuts or milk—which limits the usefulness of the whole enterprise to people like Mansmann: They think GMOs may be carrying heretofore undiscovered allergens. (If you're thinking, Well, what do the clinical trials with humans show? The answer is: They're nonexistent because, the biotech firms say, they are impractical, and, again, GMO foods are basically presumed safe and thus don't undergo near the level of scrutiny as new drugs.)

The most fundamental complaint from those worried about the health risks of GMO foods is that hardly any of the research is independent; the biotech firms either conduct or pay for the studies forwarded to the government, and they also pick and choose which ones to submit. "The scandal is that the USDA does not force the companies to give results of trials that had negative outcomes," says Harwood Schaffer, PhD, a research assistant professor at the University of Tennessee's Agricul-tural Policy Analysis Center. "We've seen this in medicine: You only get the data that the [industry] wants you to see." Schaffer also points out that the biotech firms consider their research proprietary, so there's no record for the public to inspect: "Maybe the GMO companies aren't hiding anything, but the question is: Does the public have the right to know?"

One of my last stops in Cincinnati was the office of affable Australian-born immunologist Simon Hogan, PhD, who, interestingly, was the lead author of one of the few independently funded GMO-food studies. In the early 2000s, Hogan's interest was piqued when he learned GMO peas were being developed in his native country, so he decided to investigate the new product. "I felt there was a fundamental lack of knowledge on whether GMOs could have an effect" on animals (and possibly people).

He was surprised by the results: Mice given the GMO peas had inflammatory reactions such as "mucus hypersecretion," "pulmonary eosinophilia" (eosinophils in the lungs), and airway hyperresponsiveness ("the lungs were twitchy," says Hogan). Most important, the peas may have "perturbed" a tolerance mechanism in the mice, leading to enhanced immunreactivity. When the study was published in 2005 in the Journal of Agricultural and Food Chemistry, there was a deluge of media coverage both lauding and decrying it—most notably on the con side, a Nature Biotechnology article called Hogan's study "mush" and charged, among other things, that mice probably aren't analogous to humans when it comes to allergies.

With all the uproar, the pea project was abruptly canceled. But eight years later, another team published a contradictory report showing that mice react to proteins in GMO peas and in conventional ones. It was funded by the European Union. (Hogan's very measured response? Good science requires multiple studies before conclusions can be drawn.)

While most people seem to tolerate GMO corn, I asked Hogan if he thought it could be making a small cohort of the population sick, as his peas did the mice. "I don't think definitive analysis has been done to answer that question, and because you don't know definitely what these [GMO] proteins could do…that's sufficient for me to say 'halt' until we know more."

With the level of penetration of GMO foods, and the fairly widespread acceptance of them in America (certainly compared with Europe, where they're banned in many countries), saying "halt" seems unlikely at this point. Definitely in the air, however, is better labeling of such products. The Connecticut legislature passed a measure this June to require it, and a whopping 96 percent of people favor GMO labeling, according to a 2011 MSNBC poll. Whole Foods Market announced this March that by 2018 everything it sells in the U.S. and Canada will be labeled for GMOs. How the store will implement that is hard to fathom given the ubiquity of industrial corn: Will the bastion of healthy eating plaster GMO stickers on practically every item on its shelves? "We're very aware of how much of a challenge [labeling] is going to be," a company spokesman admitted, adding that they're committed to it nonetheless.

My small family has been able to jettison GMOs, thanks to the local farmers we've found and our willingness to do without the vast majority of prepared foods. But my husband and I both have jobs, and there are days when we can't imagine preparing everything from scratch forever. Yet when I was sick for all that time, my life felt totally out of control. I still rue the day when I was desperate enough for a diagnosis to believe I had chronic Lyme disease, which necessitated weaning my small son from my breast before either of us was ready so I could be bombarded with antibiotics. When I think back to how suffocatingly powerless I felt, how sidelined as a wife, mother, and productive person, I just feel, well, sick. Although Dr. Mansmann told me that most people allergic to GMO corn can end up tolerating small amounts after a couple years of abstinence, each time I've dared cheat, I've awoken the next morning with a frozen left hand, a sore hip, and a facial rash. So for now, at least, the extra work isn't really a choice; it's a way of life, one that reminds me daily that our modern world is full of challenges—dietary, economic, environmental—that at times feel overwhelming. And perhaps that's the gift in this: I've had to slow down and think about my food—how it was grown, what's in it, and which trade-offs were made in the journey from a seed to my plate. That consciousness has to be worth something bigger than just my health.

This content is created and maintained by a third party, and imported onto this page to help users provide their email addresses. You may be able to find more information about this and similar content at piano.io