http://skepdic.com/vitacon.html
update: January 21, 2016. The supplement industry is largely self-regulated and many of its products don't contain the ingredients that their labels say they do. This may explain why the best scientific studies of supplements have found no health benefits and some harm from the daily use of supplements.
Several large studies have shown the futility of taking vitamin and mineral supplements on a daily basis as a hedge against some unspecified adverse health effects. Many people, however, consider daily supplements to be part of a healthy lifestyle. Some people may be overdoing it on some of the supplements, doing themselves harm instead of good.
Should everybody avoid supplements of any kind, then? Of course not. Some people have vitamin or mineral deficiencies and supplementation is necessary for them to maintain good health.
Below you will find links to articles about persons or practices relating to vitamins, minerals, or herbs. You'll also find excerpts from various items on these topics that I've blogged about. As a bonus, I mention people who make a living selling supplements at inflated prices and encouraging others to do the same with the promise that by doing so you will be on your way to riches beyond your imagination, eternal youth, increased spirituality, or something of the sort.
There are too many companies and products involved in this kind of chicanery to list them all by name. The following links should help you decide whether a particular outfit or product is trustworthy.