Consensus — slowing real science for decades
There is a surprising amount of interest in the cholesterol story of Matt Ridley’s in The Times and The Australian last week. Surprising to me anyway, because 15 years ago the other benevolent side of cholesterol was pretty clear online. Fifteen years is not a long time in human civilization, but it’s a long time in a human life. And in the case of the war on cholesterol, it’s been running for 40 years. How many people died sooner than they would have, because they followed expert advice?
Finally the official consensus on cholesterol is admitting defeat:
“Any day now, the US government will officially accept the advice to drop cholesterol from its list of “nutrients of concern” altogether. It wants also to “de-emphasise” saturated fat, given “the lack of evidence connecting it with cardiovascular disease”. “
In the late 1990′s it was widely known online (among health zealots) that our livers are mostly in charge of our cholesterol levels, not what’s on our dinner plates. Something like 80% of the cholesterol in our blood came from our own livers, not the food we eat. Way back then, it was also known that our bodies use cholesterol to make things like Vitamin D, and er… sex hormones. (How did the mass media miss that.)
“Cholesterol is not some vile poison but an essential ingredient of life, which makes animal cell membranes flexible and is the raw material for making hormones, like testosterone and oestrogen.”
You might think the Internet would kill off an erroneous consensus faster…
But on the Net silly, sloppy and false information can be repeated faster too. As long as people using the web are trained to follow authority, they aren’t even looking for the counter claims. The Net could speed things up if people learned to hunt for the best arguments on both sides, but who are we kidding – even science journalists are not trained to do that.
People are probably still under the illusion that newspapers as a source of risky, cutting news, but the mainstream press is so timid against the mainstream dogma that science-journalists are a part of the science problem.
The consensus on cholesterol has run for a long time on nothing more than argument from authority, and a few not-well-done analyses:
In the 1950s, an upsurge in heart disease in American men (probably caused mostly by smoking) led the physiologist Ancel Keys to guess that dietary cholesterol was to blame. When that seemed not to fit, he switched to saturated fat as a cause of high blood cholesterol. To make his case he did things like leave out contradictory data, shift points on graphs and skate over inconvenient facts. He then got big charities and state agencies on side and bullied his critics into silence.
His most famous study, the seven-country study, started out much larger; he dropped 16 countries from the sample to get a significant correlation. Add them back in and it vanishes. Hidden in his data is the fact that people in Corfu and Crete (in the same country) ate the same amounts of saturated fats, but the Cretans died 17 times more frequently of heart attacks.
In the 1970s, the famous Framingham Heart Study stumbled on the fact that people with high cholesterol over the age of 47 (long before most people have heart attacks) lived longer than those with low cholesterol, and that those whose cholesterol dropped faced higher risk of death. But the consensus ignored this and sailed on.
If challenged to show evidence for low-cholesterol advice, the medical and scientific profession has tended to argue from authority — by pointing to WHO guidelines or other such official compendia, and say “check the references in there”. But those references lead back to Keys and Framingham and other such dodgy dossiers.
I did a ten second search in web archives and found a few 1990s papers (fairly randomly picked). Get a load of the man who ate 2 dozen eggs a day and had normal cholesterol!
“Lack of Association Between Cholesterol and Coronary Heart Disease Mortality and Morbidity and All-Cause Mortality in Persons Older Than 70 Years”, JAMA, 1994
Normal Plasma Cholesterol in an 88-Year-Old Man Who Eats 25 Eggs a Day — Mechanisms of Adaptation, 1991
“ The consistency of the clinical and the epidemiological data demonstrating that dietary cholesterol has little effect on plasma cholesterol in most individuals raises a number of questions regarding the justification of population wide restrictions on dietary cholesterol intake and egg consumption.” J Am Coll Nutr. 1997
Any readers with insights into why the cholesterol consensus lasted so long, and why and how it was finally undone? Are there any lessons here?
In a different article, Matt Ridley wants an inquiry into this “epic blunder”:
Matt Ridley, a Tory peer and science author, yesterday said there should be an inquiry ‘into how the medical and scientific profession made such an epic blunder’.
He described the change of advice in the US as a ‘mighty U-turn’ and said studies linking high cholesterol and saturated fat in food to heart disease were ‘tinged with scandal’.
The U-turn, based on a report by the committee, will undo almost 40 years of public health warnings about eating food laden with cholesterol. US cardiologist Dr Steven Nissen, of the Cleveland Clinic, said: ‘It’s the right decision. We got the dietary guidelines wrong. They’ve been wrong for decades.’ – dailymail.co.uk
h/t Waxing Gibberish, and Marvin