The last time Ben Carson stepped onto a debate stage, he was asked about something he had never really questioned. Why had he endorsed the nutritional products of Mannatech, a Texas-based company that was forced to settle a 2009 wrongful marketing lawsuit? What did that endorsement say about his “judgment”?

Watching at home, Barbara Rickett was dumbfounded.

“I happen to be with the same company and saw him 12 years ago at a conference, where once he finished speaking, 5,000 people jumped out of their chairs,” said Rickett, 74, after a Carson appearance recently at Colorado Christian University.

Rickett shook her head at the CNBC reporter’s arrogance, her American flag earrings rattling. “My husband and I both had tremendous help because of that product,” she said. “I can tell you, my husband might not be here if he hadn’t taken it.”

The Mannatech moment was an unusual “gotcha.” Carson has given paid speeches for the company, which sells dietary supplements and other products intended to provide health benefits such as a stronger immune system. His most recent speech — in 2013 — earned him $43,000. He once erroneously thanked the company for a multimillion-dollar endowment to John Hopkins University, where he worked as a neurosurgeon. And he has continued to endorse Mannatech’s wares.

“I use the products myself,” Carson told The Washington Post. “My wife uses the products herself. We pay for them ourselves. I’ve been sick much less since I’ve been using the products, so I believe in them.”

Yet, in defiance of the facts, Carson professed ignorance on the debate stage about any “relationship” with the company. He spent two days following the debate denouncing the questions about Mannatech as “propaganda.”

And his most ardent supporters don’t care.

Carson’s campaign, which has climbed to a lead in polls in Iowa, has defied political expectations all year. He has fended off coverage of “gaffes” about gay rights, the origins of the Earth and the purpose of the pyramids. Nothing has slowed him, and the Mannatech flap may be a short lesson in why. Glyconutrients, or neutraceuticals — health supplements that promise almost miraculous results — are constantly being pitched to conservatives by voices they trust.

The commercial breaks on talk radio and the sidebars of conservative Web sites brim with products that promise life without diabetes, memory improvement and the elimination of stubborn belly fat. Some companies, like Mannatech, come off as merely overzealous in the promise of what some nutrients can do. Others spin amazing yarns about cures foretold in the Bible or suppressed by the government.

Conservative pundits generally choose one of two teams. Some bemoan the ads. Some indulge and sell their own products.

Jim Geraghty, the National Review columnist who first wrote about Carson’s “Mannatech problem,” fit into the former camp. So did Erick Erickson, who stepped down as editor of RedState.com this year. In 2007, the influential conservative site was sold to Eagle Publishing. By 2011, a provision of the contract that gave him control of the site’s e-mail list had expired. Suddenly, Erickson saw his brand advertising a “secret cure for cancer” allegedly used by Ronald Reagan, and an Alzheimer’s-reversing drug prohibited by “Obama’s deadly FDA,” referring to the Food and Drug Administration.

In an interview, Erickson said he would be happy if his name were no longer associated with ads like that. He also offered a theory as to why the companies pitch to conservatives.

“I can tell you that demographically, conservative audiences tend to be more individualist and focus on self-reliance themes,” he said. “Liberals get scammed in other ways. To be fair, though, it is also worth noting that conservatives have typically had to rely on these advertisements because liberals are far better at organizing harassment and boycott campaigns than conservatives.”

Conservative media also sometimes court the advertisers. Newsmax, the conservative site founded by Christopher Ruddy, features links to miraculous-sounding products next to original reporting.

“When I saw Mannatech being discussed at the debate,” Ruddy said, “I looked up the company and said, ‘Reach out to them, they should be advertising this product on Newsmax.’ ”

A typical link on Mannatech’s health section promises a “weird trick” to cure “cancer, joint pain, Alzheimer’s” with a simple “anti-inflammation kit.” The pitchman, retired neurosurgeon Russell Blaylock, went on at length about issues including the threat of genetically modified food and the way big business suppresses the truth about medicine.

“They funded phony research and flooded the medical literature with false information, claiming these plant extracts were harmful,” Blaylock wrote. “The mainstream media regurgitated this propaganda, and that’s why you see articles stating natural nutrients are both ineffective and harmful. Don’t believe it!”

Language like that echoes what conservatives say about big government and big media. In 2007, progressive historian Rick Perlstein subscribed to Newsmax’s list and a few others in order to “mainline a right-wing id that was invisible to readers who encounter conservative opinion at face value.” As he recounted in a story for the Baffler, he was deluged with information about arthritis cures and placenta-based wellness research.

“In the right-wing mind-set, there are good guys and bad guys, and Carson is the former and the FDA is the latter,” Perlstein said in an interview. “Epistemologies are adjusted accordingly.”

Pat Robertson, the evangelist whose strong 1988 caucus showing presaged the rise of Carson, now sells an “age-defying protein shake” — perfect for washing down his “age-defying protein pancakes.” But Carson is not the only 2016 candidate chided for endorsing un­or­tho­dox cures. Former Arkansas governor Mike Huckabee helped a South Dakota company called Barton Publishing sell a “diabetes solution kit,” and he chastised reporters when they challenged his ethics.

“If that’s the worst thing somebody can say to me, is that I advocated for people who have diabetes to do something to reverse it and stop the incredible pain of that, then I am going to be a heck of a good president,” Huckabee told CBS News at the height of the controversy.

Huckabee knew that conservatives trusted his judgment more than they trusted that of the media, or the “official” sources they might cite. That was true at Carson’s events after the debate. In West Memphis, Ark., where almost 2,000 people crowded a high school basketball court to hear the candidate, there was plenty of ill feeling directed at government bureaucrats and plenty of faith in Carson.

“The pharmaceutical companies are controlling too much,” said Peggy Korn, 74. “I don’t trust them.”

Korn’s neighbor, 38-year old Diana Corman, said that her family was acquiring a goat and planning to drink its milk raw. The government’s warnings to the contrary did not move her.

“We’ve done our own research, as supposedly free people who can think for ourselves,” she said.

Shortly thereafter, Carson took the stage. He made no mention of the debate, or of Mannatech, but he spent a little time explaining how the brain worked. “If you were to learn one new fact every second,” he said, “it would take 3 million years to run out of memory.” He sounded like someone to trust with your health.