When a doctor told Susan Levin her 4-year-old son, Ben, was autistic, she was shocked. It was October 2007, and autism wasn’t mentioned in the media nearly as much as it is today.

“I remember thinking, ‘Oh my God. What are we going to do?’ ” Levin recalls. “Everyone knew autism was a lifelong disorder and couldn’t be cured.”

Except that in Ben’s case, it could be. And it was.

The family’s journey — the many treatments tried and dismissed, from biomedical interventions to speech therapy to occupational therapy and more — is detailed in her new memoir, “Unlocked: A Family Emerging From the Shadows of Autism.”

Levin doesn’t call this particular cure a silver bullet for autism: There is no silver bullet, no one-size-fits-all approach. Rather, she credits his transformation to a number of things, including a home based and child centered social-relational program called the Son-Rise Program.

But one of the biggest factors was what was on his plate.

“Hippocrates was right when he advised, ‘Let food be thy medicine and medicine be thy food,’ ” she says.

Levin is part of a growing group of people who are paying more attention to diet — organic, gluten- and casein-free among them — as a way to treat the symptoms of autism and other disorders. So strongly does she believe in the healing possibilities of food that she’s now a family wellness coach working exclusively with families of autistic children.

While the scientific verdict is still out on diet as a cure, statistics point to a definite link between gastrointestinal issues and autism.

A 2012 study published by the Journal of Abnormal Child Psychology found a direct link between GI issues and behavior. As many as 70 percent of children with autism have gastrointestinal issues at some point during childhood or adolescence — and diarrhea, food sensitivity and constipation can cause extreme discomfort, leading to irritability, and erratic or withdrawn behavior.

But not everyone is convinced.

“Over the years I’ve been privy to a million parents, a million cures,” says Andrew Baumann, president and CEO of New York Families for Autistic Children. “Parents are willing to try just about anything.” And while he concedes that diet can have a very positive effect, he just doesn’t see it as a cure for autism: “You can’t cure something [when] you don’t know what the cause is.”

Parents are willing to try just about anything. You can’t cure something [when] you don’t know what the cause is. - Andrew Baumann, president and CEO of<br /> New York Families for Autistic Children

Kathleen DiChiara begs to differ. The former Fortune 500 executive was diagnosed with sudden onset neuropathy, which left her unable to walk. When the doctors told her there was little to be done, she went back to school to study. She’s now a nutrition educator, chef and speaker who credits an all-organic diet for healing not only herself, but her 11- year-old son, Steven, who’d been diagnosed as autistic but is no longer considered to be.

Why are people resistant to the idea of food’s effect on illness?

“It’s socially inconvenient,” DiChiara says. “They’re already struggling, and the idea of removing things from the diet is so daunting. But it’s the difference between the children who get well and the ones who don’t.”

Maria Rickert Hong, author of “Almost Autism: Recovering Children From Sensory Processing Disorder,” credits a gluten-free, dairy-free diet with the recovery of her two children from sensory-processing disorder.

“In a child with neurodevelopment disorders, the brain is inflamed, and the gut and the brain are connected,” Hong says. “Most of these kids have gut dysbiosis — an imbalance of good versus bad bacteria, like having too many weeds in your garden. When you have that, the body’s immune system is off.”

Levin and her family initially started Ben on a gluten-free and casein-free diet, later eliminating soy, corn, potatoes and rice. But as soon as one offending food was removed, she says, a reaction to another popped up.

Then they tried the Body Ecology Diet, an anti-yeast diet high in grain-like seeds such as amaranth, quinoa, millet and buckwheat. Almost overnight, Ben calmed down and started making eye contact.

Now 12, Ben is studying for his bar mitzvah. Eight years after that chilling diagnosis, he’s become more empathetic, frequently saying “I love you” to his mother, his father and sister.

Levin says his newfound compassion is nothing short of a miracle.

“It doesn’t matter what people say,” says Levin. “I have my kid back.”