Vitamins definitely can harm you, in large doses. Particularly the fat-soluble ones (A, D, E; not so much K). It's called vitamin poisoning. Definitely not one of those 'more is better' deals.
I have also heard that too much iron may not be great for you in the long run, as it may increase oxidative stress. This seems to be more of a problem as people age. I have actually been talking 'centrum silver' as this has less iron, and I think that I already get plenty from my diet.
I think I remember Rip talking about this somewheres...I think the gist of what he was getting at is that the risk of vitamin poisoning in someone whos undergoing the stresses that we're undergoing is low. I can't remember exactly. I'm also have yet to read either of Bill Starr's books (ordered em both on Thursday) so im sure i'll be more educated then.
Vitamins are a pretty diverse set of compounds, so we probably shouldn't be talking about vitamin megadosage and vitamin poisoning as if it's one single thing. Some vitamins have no known toxic effects, and others can kill you if taken in sufficiently large quantities. I haven't read Bill Starr's recommendations, but I'm sure they were more specific than, 'take vast amounts of all these unrelated substances that alter your biochemistry in different ways'.
A more in depth discussion is Bill Starr's The Strongest Shall Survive. He also uses anectodatal (spelling) evidence about the effects of vitamins and weightlifting. The book is available in the store section - get it. He goes in depth regarding nutrition for the strength athlete.
A quote from page 108 of TSSS: "I have merely hit the high spots, but those hight spots should give you a clear insight on each nutrient. Secondly, my program utilized the Europoean research for my recommended allowances. These are, in almost all cases, much higher than any recommeded dosages in this country. I never, however, recommend a toxic dosage. I can validate all my recommendations through actual research out of Europe and also from findings conducted in our own country, so the reader need not be alarmed that I am risking his health with my megadoses. My recommendations are considered megadoses, but it needs to be reiterated that athletes are megahumans. To suppose that a football player who spends six to ten hours per week in strenuous physical activity requires the same amount of any nutrient as the sedentary secretary or insurance salesman is pure foolishness, but that is often what we are aksed to believe by those who set the daily amounts for the various nutrients."
He also discusses the toxicity threshholds of the fat-soluble vitamins, what other vitamins mitigate toxicity, etc. Don't take mega doses without at least reading Starr's books or another equally trustworthy source. Don't just do what someone else from the internet does, including me.
I was taking the Animal Products for a good while. I switched from Animal Pak and Flex to different things. I am currently quadruple dosing Centrum Performance which is about as much vitamins as in "Pak" but without the other crazy minerals and about $20 a month instead of $50 or whatever the pak was costing. I also get big bottles of flax and fish oil and glucosamine/chrono and make my own "flex" It cost about half as much as well.
Since I switched I havent noticed a big difference in performance.
Thats also related to the "average" person. Who is very inactive. Most of us on this forum cant survive training by sticking to the recommended 2000 calorie diet, we simply need more food. This translates into needing more vitamins and minerals as well. Quit trying to scare people with some BS wiki write up that pertains to hardly any "average" people let alone weightlifters needing more of everything.
If you're scared to load up on vitamins than so be it but you cant just show one point of view and tell everyone they are going to die from it.