(NewsNation) — After President-elect Donald Trump nominated Dr. Mehmet Oz, a famous TV talk show host dubbed “America’s Doctor,” to oversee Medicare and Medicaid, some have been questioning possible conflicts of interest in his new Cabinet role.

Leading the Centers for Medicare and Medicaid Services is a Senate-confirmed position. Oz’s ties to online supplement brands and a history of reported health misinformation could jeopardize his confirmation.

Oz discussed viewers’ health concerns on “The Dr. Oz Show” for more than 22 years but switched gears in 2022 when he ran an unsuccessful campaign for the U.S. Senate.

Trump endorsed Oz’s Senate campaign and appeared on Oz’s daytime talk show in 2016, undergoing an on-air physical exam in lieu of releasing his medical records.

“He will also cut waste and fraud within our Country’s most expensive Government Agency, which is a third of our Nation’s Healthcare spend, and a quarter of our entire National Budget,” Trump said of his nomination on Tuesday.

Past administrators for the Centers for Medicare and Medicaid Services, which provides health care to lower-income people and people with disabilities, typically have had experience in health insurance and health policy.

The heart surgeon turned TV personality promoted healthy lifestyle habits, but a 2014 study found that he gave many medical recommendations on his show that either had no scientific evidence to support the benefits or were contradicted by existing science.

The study, published in the medical journal The BMJ, analyzed 40 episodes of “The Doctor Oz Show” and another medical talk show “The Doctors” in 2013.

“Approximately half of the recommendations have either no evidence or are contradicted by the best available evidence,” the authors wrote. “Potential conflicts of interest are rarely addressed. The public should be skeptical about recommendations made on medical talk shows.”

The homepage of Dr. Oz’s website promotes him as an advisor and stakeholder in iHerb Global, which has sold health and wellness products since 1996.

“Under federal law, he would be prohibited from making decisions that could impact his financial interests,” said Kedric Payne, with the nonpartisan government watchdog group Campaign Legal Center, to NBC News. “So that means that, as head of CMS, he would have to divest of those interests if he’s making decisions that are related to it.”

Some claims Oz has made with little or no evidence to back them up include using a green coffee bean extract for weight loss, selenium (a mineral found in soil) supplements preventing cancer, and lavender soap to help restless leg syndrome.

In 2014, Oz faced a Senate subcommittee about his endorsement of weight-loss products.

“The scientific community is almost monolithic against you in terms of the efficacy of a few products that you have called miracles,” said then-Sen. Claire McCaskill at the hearing.

 In 2018, Oz settled a lawsuit, in which he was accused of exaggerating the benefits of weight loss supplements, for $5.25 million.

It is unclear when the Senate will complete the confirmation process for Trump’s nominations.