Foxtel will take no action against a widely criticised host of a popular program which has been attacked for backing products making false health claims.

Late-night infomercial host Dr Mehmet Oz, who rallies millions of viewers to buy unlikely products like fat-busting coffee beans, has been roasted in an open letter from 10 US scientists.

His show appears on Channel Seven’s graveyard shift and Foxtel channel Arena, which has not scheduled the episode in which he defends himself against the criticism.

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The letter, drafted by four scientists who are pro-genetically modified foods, has called on Dr Oz’s employer, Columbia University, one of the world’s top universities, to dump him from his position as vice chair of the Surgery Department.

“He has manifested an egregious lack of integrity by promoting quack treatments and cures in the interest of personal financial gain,” reads the letter signed by graduates of other Ivy League universities.

“Dr Oz is guilty of either outrageous conflicts of interest or flawed judgements about what constitutes appropriate medical treatments, or both.

“Whatever the nature of his pathology, members of the public are being misled and endangered, which makes Dr Oz’s presence on the faculty of a prestigious medical institution unacceptable.”

The letter takes aim at Dr Oz’s “baseless and relentless opposition to the genetic engineering of food crops”.

Dr Oz replied in a 30-second video address, citing freedom of speech as the reason he should be able to continue.

“No matter our disagreements, freedom of speech is the most fundamental right we have as Americans, and these 10 doctors are trying to silence that right,” he says.

“I vow to you right now, we will not be silenced. We will not give in.”

Columbia University also backed Dr Oz’s freedom of expression.

“Columbia is committed to the principle of academic freedom and to upholding all faculty members’ freedom of expression for statements they make in public discussion,” a Columbia statement said.

In July 2014, Dr Oz was hauled before a US Senate Committee where he admitted some of the untested medications he pushed on television “did not have the scientific muster to present as fact”.

The lead writer of the letter against Dr Oz, Henry Miller, has advocated for GMOs in the past and served as a Food and Drug Administration drug regulator, the Guardian reported. Another signatory, Glenn Swogger, also backed GMO, the report states.

Two other signatories are senior members of the American Council on Science and Health, which advocates for GM foods and fracking, acting president Gilbert Ross and board member Jack Fisher.

Melbourne-based anti-genetically modified foods campaigner Scott Kinnear, whose organisation the Safe Food Foundation supported WA farmer Steve Marsh who lost his organic certification after his neighbours’ GM crop allegedly affected his, sympathised with Dr Oz.

“Some people like to break new ground, they like to stimulate debate,” he said. “That’s probably why they’re going after him.”

He said “every time” a prominent figure brings up labelling of GM foods they are attacked.

“Anyone who opposes GM foods who is a heavy hitter, who has a high profile … who come out publicly against GM are attacked and vilified,” he said.

“These companies have a lot of influence, they spend a lot of money on Capitol Hill (the US parliament).”

Foxtel spokesman David Sims said “we don’t have anything further to contribute to the story”.

Channel Seven also declined to comment. Its editorial policies refer to editorial, news and public affairs programming, which must conform with relevant codes of conduct.