Mehmet Oz, MD, the Columbia University thoracic surgeon who gained fame first in books and more recently with his syndicated television show, has run afoul of the Food and Drug Administration with his report about levels of arsenic in popular brands of apple juice.
The FDA called the report "irresponsible and misleading" and another TV doc, ABC's Richard Besser, MD, accused Oz of fear-mongering.
In a recent episode of The Dr. Oz Show, Oz reported that five brands of apple juice -- Minute Maid, Apple & Eve, Mott's, Juicy Juice, and Gerber -- all contained some level of arsenic and suggested that this was a cause for concern.
The show used an independent laboratory, EMSL Analytical, to test dozens of samples from three U.S. cities to compare the level of arsenic in the juices to the Environmental Protection Agency's safe standard for drinking water, less than 10 parts per billion.
At least one sample for four of the five brands -- excluding Minute Maid -- came in above that threshold. The highest level measured was in Gerber apple juice, at 36 ppb.
The segment earned a stiff rebuke from representatives of government, industry, and academia for causing unnecessary alarm, even before it aired.
The criticism centered primarily on Oz's testing methods, which provided a level of total arsenic in the juices. The results do not provide a breakdown of the levels of the two forms of arsenic -- organic and inorganic.
In heated confrontation aired on ABC's Good Morning America, Besser not only blasted reporting of only the total arsenic numbers but also charged that relying on a single lab to test for arsenic fell far short of scientific standards. Oz, however, refused to back down and maintained that he acted responsibly.
According to the FDA, arsenic is found in the environment in both forms, either as a result of natural processes or the result of contamination from human activities. In the U.S., some pesticides used up until 1970 contained arsenic.
The organic form of arsenic is "essentially harmless," according to the FDA. The inorganic form can cause problems at high levels or with a long period of exposure.
In a letter sent to The Dr. Oz Show before the segment aired, Don Zink, PhD, senior science adviser in the FDA's Center for Food Safety and Applied Nutrition, wrote, "The FDA believes that it would be irresponsible and misleading for The Dr. Oz Show to suggest that apple juice contains unsafe amounts of arsenic based solely on tests for total arsenic."
The FDA said it has been testing for arsenic in apple juice for several years. The juice is first screened with a test for total arsenic because it is rapid, accurate, and cost-effective, according to Zink. Only when the total level of arsenic is greater than 23 ppb does the agency employ the more complex inorganic arsenic test.
"The vast majority of samples we have tested for total arsenic have less than 23 ppb," Zink noted.
In a second letter to the show, Zink informed the producers that the FDA had performed its own testing on samples of apple juice from the same lot that yielded the highest level of arsenic in Dr. Oz's investigation. All of the results ranged from 2 ppb to 6 ppb.
"In short," Zink wrote, "the results of the tests cited above do not indicate that apple juice contains unsafe amounts of arsenic."
In an email to ABC News and 鶹ý, Aaron Barchowsky, PhD, a professor in the department of environmental and occupational health at the University of Pittsburgh, said that he agrees with the FDA's conclusion.
"It is the inorganic form of arsenic in the environment that is toxic, and measuring total arsenic is not informative," he wrote. "I support the comments by the FDA and agree that the Oz show analysis is incomplete and probably misleading."
On its website, the FDA said that it has a standard for an unsafe level of arsenic in water but not in apple juice for two main reasons -- the consumption of water is much greater and most of the arsenic in water is the unsafe inorganic form, whereas in fruit juice, most of the arsenic is the organic form.
Henry Miller, MD, a fellow at the Hoover Institution at Stanford University and formerly the founding director of the FDA's Office of Biotechnology, criticized Oz for failing to provide evidence that the levels of arsenic found in the apple juice were dangerous.
"Unless there is evidence that a substance is present at sufficient exposures and levels to cause harm, warnings about its presence in food (or in our bodies, for that matter) is irresponsible alarmism," he wrote in an email. "This is the same sort of rubbish peddled by radical environmental activist organizations about pesticides."
This article was developed in collaboration with ABC News. 