Josh Landsberg wasn't prepared to give up the pizza and hero sandwiches that had long been a staple of his diet, fueling the four-sport athlete and scholar after rigorous workouts and study sessions.

But that's exactly what he had to do after he was diagnosed with celiac disease in the 10th grade.

The hereditary autoimmune disorder is what had long made him have difficulty processing gluten, a protein found in rye, barley, wheat, couscous and other grains and starches. Though it was tough for him to adjust to a new diet, he told friends not to worry, that there were people in the world with far greater burdens.

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It's still difficult for Landsberg, 18, to watch friends dine with ease on the foods he once adored, but he's learned to cope.

"At the end of the day, it's only food," said Landsberg, one of Newsday's 12 Extraordinary Seniors. "I feel blessed that it's manageable for me."

In his role as student ambassador for the National Celiac Disease Society, Landsberg, who lives in Jericho, helps manage its fundraising events. Outside of sports and charity work, he's fascinated with world languages.

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"When I study a language, it's almost like I know what it feels like to actually be in that culture," he said. "I took French in middle school and loved it, and I wanted to see how different Chinese would be. I enjoy the contrast between all three languages [including English], and I plan on studying as many as I can in college."

Aristea Kakounis, Landsberg's Advanced Placement U.S. History teacher, said he was always more interested in learning than in his grades, though he always scored high.

Joshua Landsberg, a senior at Jericho High School, sits inside the school gymnasium, Wednesday, June 3, 2015. Photo Credit: Steve Pfost

"He loved the story that came with history," Kakounis said. "It's rare to find a kid like that."

@Newsday

HIGHER ED:

Landsberg will attend Duke University.

FRESHMAN FAST-FORWARD:

"I'm really looking forward to meeting a ton of different people from all over the world."

WHAT MAKES YOU EXTRAORDINARY:

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"When I think about something and I know I want to do it, I work as hard as I can to achieve it -- in the classroom and out."