Your guest blogger is wise to remain anonymous. His/her post is irresponsibly misleading, without any conclusive evidence to back it up. "May be harmful" is true of almost anything, from sex to sunshine. This blog serves only to confuse and terrify, without offering any useful information. Antioxidants are a natural component of fruits and vegetables. Eating them is healthful, period. If your blogger would like to say which fat-soluble vitamins are supposed to be harmful, that might be helpful, but since no such mention was made, "it's interesting" serves only the pretense of his/her erudition. I highly recommend "Fats That Heal, Fats That Kill", by Udo Erasmus, PhD. for anyone interested in factual information on nutrition, from the molecular level up.

It really would be appreciated if you didn't put up scares like that without at least SOME kind of proof or evidence to back it up.
Otherwise you just instill more fear and confusion into people without helping them out at all.

There are a couple of points to make here but let me start by saying it is possible that the two commenters did not see the marked link to the news report about the study in the original post that would have given them information on the study, the largest ever performed on vitamins. I’ve included it here again:
http://www.ewg.org/news/story.php?id=5873

Readers can also go to the source of the news story here:
http://jama.ama-assn.org/cgi/content/full/287/23/3116?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=vitamin&searchid=1&FIRSTINDEX=0&resourcetype=HWCIT
the article is in the Journal of the American Medical Association (registration is required but the article in question is free, and nice bonus by JAMA given the interest in the subject-check it out if you have time).

This all really misses the point, though. The post is getting at the point that the press usually runs away with the speculations about what the conclusions might be and forgets about the limitations, which is how we got to this point in the first place. As a proponent of separating the conclusions from the conjecture, my last paragraph is clearly my own thought (e.g. ‘it’s interesting’). There’s nothing wrong with musing, as long as everyone knows what you’re doing. This is exactly where the press trips up, it doesn’t like guesses, and the actual conclusions usually aren’t exciting enough for their taste. In this respect then, I’d agree with the general sentiment of the comments, that you better not report unless you hew closely to the facts and identify when you part ways.

As to the other points:

I fail to find anything ‘terrifying’ about the post. That may just be me. If Mr Roettinger feels terrified by the fact that the largest study on vitamins to date in a prestigious journal found that many commonly taken vitamins are not helpful and may actually be harmful, there is little I can do about it. The truth is what it is. In fact, if anything, I softened the findings by saying they ‘may’ be harmful; in the context of the study, they were harmful. Based on the facts as scientific community knows them right now, it’s probably not a good idea to take vitamin supplements. Should the press or health advocates simply whistle past the facts because they are afraid that someone might be scared?

Speaking of partial and shaky science, I, nor the general biomedical establishment, can recommend ‘Fats that Heal, Fats that Kill’. But this is really the best part; not only do you not have to worry about which supplement to take for good health, you don’t have to shell out hundreds of dollars per year to buy into the theory of the month book club! As everyone from your grandmother, your doctor, this doctor, and that nagging voice in the back of your head knows: exercising plus eating good food, not too much, mostly plants puts you on your way to good health. I trust that's not too scary.

- A.T., Guest Blogger

Thanks to your anonymous guest blogger, "A.T.", for supplying the link to the article in question, in which I found a much less inflammatory bit:

"Most American adults probably won't see any effect, positive or negative, from taking a daily multivitamin, and participants at the NIH conference did not recommend discontinuing their use."

It seems that what we have here the longstanding issue of whether or not taking supplements is of any value, and whether or not they may cause harm. From time to time, the press seizes an isolated case where someone overdoses on ephaedra, or gets an uncomfortable flush from taking niacin on an empty stomach, in order to create a sensation and generate interest in the news. Fine, that's their job.

The health food industry does capitalize on people's wish to be as healthy as they can be, but as the NIH admits,no harm is done by this (except for the cost to consumers, which they don't seem to mind). True, the un- or insufficiently- informed consumers in many cases take supplements willy-nilly, with little or no understanding of the benefits (if any).

On the other hand, many thousands of people become ill, suffer side effects and complications, and/or die every year from taking medications prescribed by their doctor. The "may be harmful" reference to supplements is frivolous when placed in the context of death by prescribed FDA-approved medications.

Regarding "A.T."'s and "the general biomedical establishment"'s inability to recommend "Fats That Heal, Fats That Kill" - again, speaking from the shadowy cover of anonymity, it is all too easy to cast doubt on the serious (and well established) work of another by obliquely referring to it as "shaky science". Has "A.T." actually read it? Would "A.T." like to give any substantial reason for not recommending it, based on something besides prejudice? It would seem more in the spirit of scientific inquiry and intellectual honesty to encourage the public to read material that might cause one to question established convention (especially the medical profession, which has caused many more deaths than the vitamin industry). Where is the harm in reading?

I am glad to find out that he based his info on that latest article printed in the JAMA because I have already read about how unreliable that particular study was. I have found that just because their has been a study done, doesn't mean the results are valid. You have to look at HOW the study was done, the biases, the error bars, etc. Although there was a particular article I wanted to share showing precisely how that study was flawed, but I forgot to bookmark it back when I was doing research on this.
Although this link is basically saying some of the same things:
http://www.organicconsumers.org/articles/article_4399.cfm
Although perhaps some of these other thinks might be helpful to some people who are curious for some more insight into the topic at hand, even though they more have to do with synthetic vs natural vitamins: They don't show the actual case studies, but they are a good start to further research:
http://www.organicconsumers.org/articles/article_4331.cfm
http://www.organicconsumers.org/articles/article_4322.cfm
http://honestnutrition.blogspot.com/2007_02_01_archive.html

As to the fact that people at NIH don't see much risk/benefit for people taking a multivitamin, this is confusion and cherrypicking. I'd agree with the NIH about the multivitamins. The study, however, did find worse outcomes for those that took suppliments of particular vitamins. What Mr Roettinger hasn't made the connection with is that most supplements of vitamins E and A, for example, have much larger levels than contained in the multivitamin. So where are we? Vitamins probably don't do anything, and sometimes may be harmful, in fact were, in the actual study. This is exactly what is said originally. I'm not sure why all the huff. I'm also not exactly sure what deaths due to medications has to do with any of this.

I have looked over parts of 'Fats that Heal, Fats that Kill' as well as read particular chapters in depth. I disagree with conclusionsand believe that the book carries the same flaws that were discussed in the original post. There are a set of base facts that have been shown but the recommendations are based on speculation along. Similar speculation could come up with wildly different recommendations. I do agree with the author on the fact that the commercial fats should be avoided. Could the book be right on other topics? Possibly but it's not supported. In my opinion, doubtful. Again, most people know how to be healthy, there really aren't any special methods or tricks or pills that are needed.

After that, I'll leave it to readers to go to the sources and make up their minds.

-A.T.