Is arsenic in our kid’s apple juice?

The short answers to this question, depending on who is answering, are either: “Yes!” or “Yeah, but no need for concern.”

The difference is at the center of a dispute that’s playing out today between federal regulators and the popular television medical expert Dr. Mehmet Oz.

The basics: “The Dr. Oz Show” plans to today air a segment about arsenic in juice. The premise is that that a study commissioned by the show found significant levels of arsenic in several store brands of apple juice. The show promo makes a case that parents should be “shocked.”

But the Food and Drug Administration has already launched a campaign to counter the show’s assertions. Officials have posted fact sheets about the safety of apple juice to the FDA Facebook page and Web site as well as letters [here and here] that a senior science advisor sent to the show’s producers disputing their analysis.

“We’re concerned that people are going to start thinking their juice is unsafe when that’s not case,” said Stephanie Yao, an FDA spokeswoman.

Yao said the FDA has made it clear to “Dr. Oz” producers that their testing premise was erroneous because there was no differentiation between inorganic and organic arsenic. It’s a key difference because only inorganic arsenic is toxic.

Tim Sullivan, a spokesman for the show, said the producers “stand by the results.” He said a point of the segment is to highlight that the FDA allows juice to have higher levels of total arsenic than it allows water to have. This should concern parents, he said, especially since so much juice is imported from countries without much quality control.

It’s true that the FDA considers it a red flag if 23 parts per billion of arsenic is found in a sample of apple juice but only 10 parts per billion of arsenic in bottled water, Yao said. But, she said, water contains higher amounts of inorganic arsenic — the type that should concern consumers — so regulators have set the overall level of concern lower for water.

More on the dispute is expected to be posted on the show’s Web site later today.

The back-and-forth may matter less for its details and more in the larger questions at play. How much can we trust the imported food we give to our children? How much can we trust our own government’s regulation? How much credence should we give to self-appointed whistleblowers in the media?

There are no short answers here either.