"To organize a large-scale U.S. effort on behalf of autism and autism epidemiology will take a lot of time," researcher Walter Zahorodny told Newsweek.

Medical experts, along with people on the autism spectrum, told PolitiFact that Kennedy’s portrayal was skewed.

Robert F. Kennedy Jr. announces plans to launch a national registry that keeps track of Americans with autism.

Some have quit in frustration. The leading nutrition scientist at the N.I.H., Kevin Hall, recently resigned, saying he was being censored. Jim Jones, the chief of the F.D.A.’s food division, quit last month, saying “indiscriminate” layoffs would make it “fruitless” for him to continue.

Health Secretary Robert F. Kennedy Jr. and FDA Commissioner Marty Makary said on Tuesday that the agency plans to remove petroleum-based synthetic food dyes from the U.S. food supply by revoking authorizations of some and working with industry to voluntarily remove others.