In an unfortunate case of trying to curb his allergies, an 11-year-old boy has gone blind from following a very restrictive diet of only pork, lamb, potatoes, apples, cucumber and Cheerios. His mother put him on the diet in an effort to regulate his severe eczema.

In a study published in JAMA Pediatrics Clinical Challenge, doctors say the boy, who was treated at Toronto’s Hospital for Sick Children, experienced progressive vision loss, night blindness and light sensitivity over the course of eight months. He had also been complaining of dry eyes.

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“He had very severe eczema and some patients will try to eliminate common allergens — like soy, milk and peanuts — to try and help with eczema,” says Dr. Dustin Jacobson, lead author of the study and pediatric resident at the University of Toronto. “In his mother’s experience, they slowly eliminated foods that seemed to cause his eczema to flare. He seemed to be somewhat of a picky eater as well.”

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By the time the boy was taken to doctors, he was already experiencing blurry vision, Jacobson says, and it quickly escalated to overt blindness. He was limited to detecting hand motion at 30 centimetres, which classifies him as legally blind. His impairment is due to a severe vitamin A deficiency due to his limited diet.

Once at Sick Kids, doctors administered daily megadoses of vitamin A of 200,000 international units (IU) for two days, followed by another megadose two weeks later. For reference, the normal recommended daily intake is approximately 2,000 to 3,000 IU.

“His sight has improved with treatment, but it’s impossible to tell to what extent his vision will continue to improve,” Jacobson says. “He is at risk of lifelong visual impairment.”

The study notes that “vision loss associated with vitamin A deficiency can be reversible; however, in cases with established optic atrophy, as was the case in this patient, a degree of vision loss is likely permanent.”

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Vitamin A is typically found in leafy green vegetables, sweet potato (with skin), liver and dairy. In the case of this boy, Jacobson says vegetables should be introduced to his diet, as well as vitamin A supplements.

“Deficiencies of niacin, B12, zinc, vitamin D, iron, vitamin C, and many more can lead to devastating health consequences. Parents should help promote their children eating a varied diet that follows the general guidelines of the Canadian food guide.”

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