This fine read has taught me a bit about experimental design and medical ethics, and quite a lot about the placebo effect. One factette that lodged in my mind: when a new drug is released, older drugs that treat the same condition actually become measurably less effective. That is to say: if they previously had a 60% chance of curing the condition within a certain time, that chance may drop to 40% when the new drug becomes available.
No-one is quite sure why this should happen. Could be something to do with experimental design or sample selection. But Goldacre's money is on the placebo effect - the doctors themselves, being subject to the ferocious marketing tactics of drug companies, have more faith in the newer treatment.
Another case is the story of fish oil. Thanks to the charlatanry of "nutritionists", most journalists now accept as Proven Scientific FactTM that fish oils are good for the brain, and feeding fish-oil capsules to children makes them perform better in class. All over the country, to hear Goldacre tell it, parents are shovelling pills into their children daily; in some schools, not doing so is considered tantamount to child abuse. And yet there's not a shred of clinical evidence to support this superstition.
Big-time win for the drug companies. They've successfully persuaded a whole generation that "taking pills" is a normal activity for healthy people.
I thought of this today when I saw this story in today's paper. "Wear gloves to avoid cancer in the car" says the headline. Even by the Herald's standards, that's a pretty opaque headline - is there some nasty type of cancer that affects drivers, carcinogens in that rubber-like material that coats the steering wheel perhaps? But no. The story turns out to be about exposing your skin to sunlight while driving. Glass, it transpires, doesn't stop all UV radiation.
Plain, clear vehicle glass blocks only 37 per cent of UV-A radiation. The main risk comes from long or frequent trips exposed to sun through side windows.Intrigued, I did a little more research into UV-A and UV-B.
UV-B is the stuff that causes sunburn, and plain ol' glass stops nearly all of that. But that nasty UV-A gets through, and according to the Cancer Society, that too is dangerous, even though it doesn't burn. I'm not qualified to comment on the health risks of UV-A, but my suspicions were aroused when I came to this line in the story:
The issue was highlighted by sunscreen maker Oasis Beauty, which urged drivers to apply sunscreen before driving.The Cancer Society, to its credit, is leery of that suggestion. It recommends instead long sleeves and, optionally, gloves. (In summer, no less.) But, I had to wonder, what sort of weight should we apply to health advice from a company that's selling a product?
Even these measures are only necessary if you're driving long distances, because UV-A takes a good long exposure to do harm, and laminated windscreen glass stops 80% of it - it's only exposure through the un-laminated side windows that's really dangerous. So long sleeves should pretty much eliminate the risk, at no real cost.
But as with pretty much everything health-related, there's another side to this story. No UV-B means no vitamin D. And if you're of the male persuasion, no vitamin D is a recipe for, among other things, prostate cancer.
Over 200 people die of skin cancer in New Zealand every year. But roughly 600 men die of prostate cancer. In other words, as a man, I'm approximately six times more likely to die of too little UV-B than too much. So why is all the public-health propaganda telling me to get less sun?
The obvious answer is: sunscreen is bottled, marketed and profitable. Whereas sunlight is, as yet, still free. It's a lot harder to make money by telling people to use less of a product.
And this is why our health advice is so confusing: because it's all coming from people who have a product to sell. Nobody is disinterested. Nobody is on our side.
Health advice I believe in: eat fresh vegetables, don't get too fat or too thin, don't smoke or drink to excess, and last but not least, don't let the bastards grind you down. Everything beyond that, I'm now convinced, is guesswork based on information that is partial in every sense of the word.