Well, they could be biased...but then again, they have no miracle claims for vitamin C there. And I did say they were a good starting point, and they have reference cites to support health claims. So you can read the references to see if the evidence, IYO, is strong enough to support the claims.
They do it because there is a profit involved. If a cheap, not patentable supplement works to correct or prevent a health disorder, then a costly drug is not needed/prescribed. That cuts into potential profits. If the benefit of a supplement becomes widely known and, therefore, more generally used, that will cut into profits significantly.

OTOH, companies can make a profit on the other side as well, they can put in a little, ineffective or inert form/amount of a proven effective supplement, make health claims for their "improved" product and sell their product at either a premium price or make it more marketable.

True. That's where self education and knowledge come in. Bogus science is bogus science, no matter who is paying for it. The same can be said of good science as well, though. That's why media reports need to be ignored and original studies, on which the media reports are based, need to be read and the "evidence/facts" analyzed to find the truth.

quackwatch.com is completely unreliable in my estimation. Kind of a "hate site" focused on natural/alternative health. I think there is good evidence they are funded by the pharma industry.

One of the problems with clinical trials is that they come from the viewpoint of finding a "magic bullet" which is typical for "scientific perspective".

Alternative health is best viewed from a holistic point of view. i.e. improving the health and optimum functioning of the body/mind/spirit. There are countless studies showing that Vitamin C is important for improved health. From this viewpoint reversing cancer may involve completely different approaches for different individuals dependent upon what body systems are malfunctioning, vitamin c is probably beneficial, it may be the complete solution for some but probably not for all.

Vitamin D3
CoQ10
Magnesium
Fish Oil
Probiotics

Quackwatch is probably owned by big pharma

Well, when LEF posts stuff favoring supplements, why don't we view that equally suspiciously ?

I think there are biased sources everywhere, and we may be picking what suits us or what we like ....

We are an economic society that is true and much of our actions are directed towards economic gain. I think it comes down to integrity. For instance the cigarette manufacurers were clearly out of integrity when they hid or denied health problems related to smoking. And now we are seeing evidence of similar circumstances in the pharmaceutical industry. I am not saying that all of them are "evil" but I think they are suspect in many cases.

Certainly it can happen the the natural health arena also but it seems to me that the FDA and the press are looming over that industry looking for any "newsworthy" event. In most cases supplement manufacturers are prohibited form making health claims by the FDA. I am surprised that the alternative health market is as large as it is given the restricted atmosphere under which it must exist.

I guess I am more likely to trust someone who is advocating a holistic health solution and stands to make only a modest amount of money from it compared to a huge corporation that is making billions. Holistic can be viewed as "integrity for the body", there may be some charlatans but not so many I think.

I partially agree, amazednow.

But human nature is human nature - if exploitation is possible, exploitation will happen, sooner or later. The "profit motive" will always win over scientific truth and/or ethics.

The supplement market is not small, its fairly large, and, whats far more important, growing rapidly. We should be wary of claims/articles by supplement manufacturers (or people sponsored directly or indirectly by them). Lets apply the same standards and skepticisms to their claims.

Its nice to target only the Government and FDA, it feels good (I think we all have some anti-establishment genes ) ... but doing that would be selective application of our skepticism.

I don't know about billions, but holistic or not, supplements are big business, and like any other big business, are quite prone to saying anything to get you to empty your wallet. They are certainly not all crooks, but I see no reason to simply trust them any more than the government. If they're making money off me, I'm going to be cautious.

I am not suggesting that supplement manufacturers get a "pass", I just believe that bias is less frequent.

Nearly all supplements are not patentable, if a supplement brand succeeded in getting a bogus study done then benefits would be shared with the many, oftentimes hundreds of brands and the resulting profits would be relatively small, perhaps not worth the risk. In the case of a patented drug the circumstance is much different.

It is common knowledge that there is a "revolving door" between the pharmaceutical industry and the FDA, many high ranking FDA employees/board members were previously in the pharmaceutical industry. This almost certainly leads to both conscious and unconscious bias towards the pharmaceutical industry.