In his book "Do You Believe In Magic? The Sense And Nonsense of Alternative Medicine," Dr. Paul Offit contends that the vitamin and dietary supplement trend that has picked up steam in recent years is ineffective, expensive and potentially deadly.

"Vitamins live under this notion that you can't possibly hurt yourself," he said. "But you can, by challenging Mother Nature and taking these vitamins and concentrating them to these exceptionally large quantities that you would never normally eat."

Dr. Offit, who is based out of the Children's Hospital of Philadelphia, warns that substituting supplements for substances found in actual food is dangerous because we don't naturally take in certain nutrients in those same concentrations when we eat. According to the Daily Mail, Offit was alarmed when he saw a tv advertisement telling viewers that they would need to drink 2 gallons of orange juice in order to get the same amount of vitamin C as the supplement.

"When you take large quantities of vitamins - 5-fold, 10-fold - greater than the [recommended daily allowance], I think the data is clear - it increases your chances of heart disease, cancer and can shorten your life," Offit said in an interview with CBS This Morning.

Offit did make some exceptions, though. The doctor does believe that pregnant women should take folic acid to prevent babies from developing spina bifida. And he also said that elderly women should take calcium because it prevents bones from thinning. Offit also mentioned that omega-3 fatty acids may be beneficial to heart health. But everything in moderation.

In his book, Dr. Offit also blasts alternative medical therapies. "There's no such thing as alternative medicine - if it works it, is medicine," he said. "If it doesn't work it's not an alternative."

Offit even went so far as to say that Apple founder Steve Jobs would still be alive today if he had sought more traditional medical care rather than alternative medicine, noting that the type of pancreatic cancer Jobs had - a neuroendocrine tumor - is cured in 95 percent of patients by undergoing surgery.

Sensational or not, experts say that Dr. Offit's assertions have not been proven either way.

"Consumers should always use caution when considering 'megadoses' of any supplements, carefully research these choices, and consult a healthcare professional with questions," the Consumer Healthcare Products Association said. "While Dr. Offit shares his own hypothesis on supplemental antioxidants in this piece, it has yet to be substantiated. Until that time, we look forward to future research that would provide guidance for public health."