Twitter CEO Jack Dorsey has recorded a podcast with a fitness personality who last month repeated an unfounded claim that “vaccines do indeed cause autism” and told his readers not to trust the fact-checking organization Snopes.

Dorsey thanked podcast host Ben Greenfield in a tweet on Tuesday, writing that he had a “great conversation.” Greenfield wrote on Twitter that the two talked about “advanced stress mitigation tactics, extreme time-saving workouts, DIY cold tubs, hormesis, one-meal-a-day and more.”

“Thanks Ben,” Dorsey wrote. “Appreciate all you do to simplify the mountain of research focused on increasing one’s healthspan! Grateful for you.”

A Twitter spokesperson pointed NBC News to the company’s advertising policies about healthcare, which note that “ads that make claims about the cure, treatment, diagnosis, or prevention of certain diseases and conditions are restricted under our Healthcare policy.”