Ben Carson credited a nutritional supplement for helping save his life from cancer, yet he never mentioned it during interviews about his illness until he started shilling for its manufacturer.

Carson was a spokesman for Mannatech, which claimed its “glyconutrients” could treat cancer, autism, multiple sclerosis, and AIDS. “The wonderful thing about a company like Mannatech is that they recognize that when God made us, He gave us the right fuel,” Carson said in a 2013 speech praising the company. On Wednesday, he denied any involvement with Mannatech.

Carson even credited the supplements as being powerful enough that he didn’t need surgery for advanced prostate cancer. Dallas Weekly reported in a 2004 interview that Carson “said his decision to have a medical procedure resulted from his concern for those people who might neglect traditional medical procedures because they had learned of his personal experience with supplements.”

The neurosurgeon told Dallas Weekly that he had his prostate removed to be a role model.

“I knew that other people with my condition might not have been as religious about taking the supplements as I had been,” Carson said.

A radical prostatectomy is a serious surgery that involves an incision either below the navel or between the scrotum and anus, as Johns Hopkins Hospital (where Carson had his) notes. Complications may include urinary incontinence, impotence, and sterility.

Dr. Carson was told that his recovery after the August 2002 surgery would be arduous and that he would not be able to return to work for six weeks. “Because of my experience with glyconutrients I was able to return to work in three weeks,” he said.

For the first two years after his surgery, though, Carson never mentioned glyconutrients.

In November 2002, Carson told the 700 Club that he was diagnosed with “one of the most aggressive types [of cancer]. I thought at one point that I was going to die.”

The interviewer asked Carson how he handled the situation and if he had any fear of the procedure. Carson said he was worried about the potential of the cancer spreading but that he was at peace with the thought of death.

Later, Carson discussed how eating better can help take care of one’s body and that preventative medicines could also help the immune system. This would appear to be the perfect opportunity to mention the glyconutrients he would later say helped him, but he did not. Mysteriously there is no mention of them whatsoever from Carson.

“Organic fruits and vegetables. Much less in the way of processed foods,” Carson said. “Snack foods are pretty much out. I don’t drink soda anymore.”

Carson also praised the surgery but did not mention glyconutrients that in 2004 he said helped him recover.

“Well, all of the cancer was contained within the gland that was removed,” Carson says. “He was able to spare my neurovascular bundles to preserve all my body functions, and the lymph nodes were negative. My status is cured!”

In another story about his recovery in Ebony magazine in January 2003, Carson also did not mention glyconutrients.

Carson said that there is a “dietary connection” to cancer and mentions pesticides and water contamination as possible causes. The doctor also scheduled the prostate surgery just six weeks after the initial diagnosis, suggesting that he thought the surgery—and not supplements alone—was necessary to save his life.

Carson also gave an address at the Niagara University commencement in May 2003 where he discussed his cancer as well. Yet there are no mentions of Mannatech or any of its products.

The next year though, Carson began telling a different story involving his cancer.

“I had a friend who was diagnosed with cancer who was given three months to live,” Carson told Dallas Weekly from his Johns Hopkins office. “He changed his diet and pursued proper nutrition. He was still around and doing well… As a result I started to look at nutritional supplements.”

Carson said the father of one of his patients told him about Mannatech and glyconutrients. After contacting the company, Carson said he was surprised by the amount of science they provided him.

“I was impressed that they did not make any wild medical claims,” he said. “The majority of their science pointed to how glyconutrients supported the body’s normal functions of regeneration and repair.

“The science made sense to me,” he continued. “God gave us [in plants] what we need to remain healthy. In today’s world our food chain is depleted of nutrients and our environment has helped destroy what God gave us.”

Carson said he then contacted Dr. Reg McDaniel, a supposed authority in glyconutrients and medical director of Manna Relief, Inc. Dallas Weekly called the group a charity that makes glyconutrients available to medically fragile children around the world. McDaniel was accused in 2006 of using his charity, the Fisher Institute for Medical Research, to fund and publish studies that were favorable to the supplements sold by Mannatech.

Mannatech was sued by the state of Texas in 2009 and forced to pay consumers $4 million and promise to prevent their representatives from alleging that products like glyconutrients cure any disease of any kind.