Okay, but don't make the mistake of the guy who says "The mainstream media is all lies - so I'll only trust what I read on shady Internet conspiracy sites". Saying that there are likely flaws in mainstream medical research doesn't license you to discount any specific medical finding unless you have particular reason to believe that finding is false. And it certainly doesn't license you to place more credibility in small, poorly performed studies that contradict large, well-performed studies, or in fringe theories that contradict mainstream theories. Unless you hold your favorite theory, be it anti-vax, paleo-diet, or whatever, to the same high standard you hold the medical mainstream, every true fact you learn about flaws in medical research makes you stupider.

The study mentioned above looks at exciting cutting-edge research over the past decade. It says that 40% or so was proven wrong. This is good and to the credit of medical science! It means the system is working as it should in retesting things and getting the false stuff out. The basis of science isn't getting everything right the first time, it's making sure everyone's work gets checked and double-checked until only the truth survives. An unreplicated study in almost any area is an intriguing possibility and nothing more; medicine is no exception. If the media makes a big deal about a new study and publishes "VITAMIN B CURES BREAST CANCER!!!" in 72 point font in the newspapers, that is an interesting fact about the media and the people who believe it, but not an interesting fact about medical science.

Good doctors are both conservative and utilitarian. They stick to older, well-proven treatments unless the advantage of a new treatment is so great that it outweighs the uncertainty and risks involved. IMHO the medical consensus has been right on the important things a surprising amount of the time.

I would strongly discourage people from bewaring statins overly much. I don't see anything by Ioannidis saying the studies surrounding statins are particularly bad. Ioannidis says research is less likely to be true if it has low sample sizes, low effect sizes, bias, and a wide net. There have been several statin trials with sample sizes in the thousands to tens of thousands (see: JUPITER, SSSS, etc.) They've found that death rate from heart attacks in people correctly prescribed statin goes down by 30%, which is not at all a small effect size. Many such trials have not been linked to statin manufacturers or anyone with an axe to grind. And because people already know statins are supposed to reduce cholesterol, there is much less of a wide net than if you were to give a bunch of people statins and, say, see if any diseases became less common - the studies had a clearly designated endpoint, which they achieved.

Are there people who suggest the side effects of statins are worse than everyone else thinks? A few, and based off of very little evidence (I believe the idea that statins cause memory dysfunction is based mostly off isolated case reports, and there are only 60 out of many years of hundreds of thousands of people on statins - basically background noise). I haven't investigated this thoroughly, but the side effects would have to be pretty darned bad and pretty darned robust to stop prescribing a drug with an NNT in the two digits (ie it takes under 100 statin prescriptions to prevent one heart attack), and I treat people trying to exaggerate drug side effects as just as real a failure mode as doctors trying to exaggerate drug benefits, and use just as much caution.

The advice in the third-to-last paragraph, except perhaps the specific singling out of statins, remains excellent.