I have just finished reading Natural Causes by Dan Hurley, an entertaining and informative look at the various degrees of fraud and flimflammery that go on in the supplement and vitamin industry. The book is marred only by Hurley's exaggeration of his case. He concludes that of all the products that fall within the heading of "dietary supplements," only vitamin D and omega-3 fatty acids derived from fish oil appear to be safe and effective. Of course, safe and effective are relative terms, but I can think of quite a few additional examples off the top of my head: fiber supplements, stevia the as a sugar substitute, vitamin C for those who don't get it in their regular diet, digestive enzymes, acidophilus and other cultures, calcium, and for that matter, I think even Gatorade has been shown to help prevent dehydration. There is certainly enough foolishness and fraud in the supplement and vitamin industries that there is no need for Hurley to overstate things to sell his book, and his thesis.