For Catlin Shetterly, cutting genetically modified corn from her diet eliminated a slew of health issues that had plagued her for years.

The Guardian reports that the 37-year-old woman from Portland, Maine, had long suffered from face rashes, joint pain, nausea, severe insomnia, chronic fatigue and a constant head cold when allergist Paris Mansmann suggested that genetically modified corn could be behind her frustrating, unexplained symptoms.

After years of unsatisfactory diagnoses from several different physicians, Shetterly was desperate, and immediately jumped on the new diet. But phasing out genetically modified corn proved to be much more difficult that it first seemed — not because of a particular appetite for the grain, but because of its almost menacing prevalence in U.S. produce.

Genetically Modified Corn In The U.S. Food Industry

"After all, how hard could it be to give up corn?" she writes in an essay published on "The answer was: way harder than I imagined. 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."

Over the years, genetically modified corn has become incorporated in a wide range of foods, assuming a weird, almost spectral presence in the produce industry. Not even protein is exempt, as most cattle and poultry farmers keep their animals on a corn-based diet.

To exclude genetically modified corn, Shetterly had to limit her diet to grass-fed beef, dairy, vegetables, and grains other than corn.

"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," she writes. "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."

A Life-Long Battle?

Mansmann had told her that if her symptoms were caused by genetically modified corn, they would begin to dissipate after about four months — the approximate time it would take her body to phase out eosinophils, a type of white blood cell that flourish as part of allergic reactions.

"Slowly, my body stopped aching, and I could walk or even jog easily, for the first time in years,' she writes. "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."

Eventually, all of her symptoms subsided. However, she describes her fight as being far from over; any incidental exposure to genetically modified corn appears to trigger the symptoms once again. For now, the tremendously restrictive diet may be her only choice.

Can Genetically Modified Corn Act As An Allergen?

In theory, everything has the potential to induce an allergic reaction in a person. Allergies are essentially an immune system response to an antigen — a substance the body perceives as foreign. A white blood cell in the body will mark the antigen to be attacked, while other immune cells release chemicals and hormones such as histamine in response, leading to an allergic reaction.

Indeed, Shetterly probably was allergic to genetically modified corn, just as others might get allergic reactions to peanuts or pollen or organic corn. If you think you have an allergy to genetically modified corn, there's only one way to find out: try cutting it from your diet and see if your life improves.