Glyphosate is the active ingredient in an herbicide heavily used in agriculture.
Mitra linked glyphosate to the rising incidence of autism, citing research by Stephanie Seneff and Anthony Samsel of the Massachusetts Institute of Technology to support his allegations.
Seneff and Samsel have written that glyphosate inhibits cytochrome P450 enzymes, which detoxify xenobiotics.
That viewpoint has been challenged by Huffington Post blogger Tamara Haspel, a food and health writer. She's also a farmer and she wrote: "Samsel and Seneff didn't conduct any studies. They don't seem interested in the levels at which humans are actually exposed to glyphosate. They simply speculated that, if anyone, anywhere, found that glyphosate could do anything in any organism, that thing must also be happening in humans everywhere. I'd like to meet the 'peers' who 'reviewed' this."
Mitra also said at the rally that those who eat organic foods are less likely to have accumulations of glyphosate in their bodies.
He wants Canadians to get tested and encouraged everyone in the crowd in front of the Vancouver Art Gallery to pay for the test of one family apart from their own.
"Government has abandoned us so we have to bypass the political process and do it," Mitra said.
He called upon people in the crowd to try to elect responsible municipal politicians, declaring that corporations already had enormous influence over senior levels of government.
"We have to kick the bums into the Pacific Ocean," Mitra said as he concluded his speech. "That is the only way we can regain our political independence. This is not just about bad health. This is not just about bad science. The Canadian independence is under attack."