I've wondered about this for a great many years, but I always come back to what Linus Pauling said. And I remember a colleague of his that said that he was probably right about Vitamin C - that he was usually right about everything.

But i have to smile when I remember an aunt of mine. She took Geritol every singe day for life. She was convinced that she would die - possibly immediately - without it. And, she absolutely knew that she was right about everything.