by Dr. Malcom Kendrick, M.D.
Author of The Great Cholesterol Con
I have been researching heart disease for nearly thirty years. Possibly the most fascinating and disturbing thing to emerge, to my mind at least, is the existence of a whole series of 'facts' which are just not true. Or, to be somewhat more scientific in my use of language, they are facts with no clinical outcome evidence to support them.
Here is one such 'fact', which is very widely accepted as true. Red wine protects against heart disease. When you try to track down a fact like this you will find, as I have done, that the evidence they rest on varies from; weak, to nil - to completely contradictory.
Indeed, if you have the time and energy required to dig deeper, you will find that most such facts are not based on any data at all. It can simply be an idea that was put forward in a medical journal, or at a conference. That is, if you can ever find the source.
Despite the lack of foundations, a strange thing then happens to certain ideas. Over the years, through a process of repetition, and multiple cross-referencing between different authors, and papers, the initial hypothesis becomes widely accepted as being true.
Why? Because everyone says.... that everyone says it is true. There will almost always be some physiological or biochemical process invoked to give it some scientific credibility. But when you look for the real hard data on clinical outcomes.....nothing.
The first time I came across an example of this phenomenon was when I started looking more closely at the 'fact' that women were protected against heart disease by their sex hormones. At one point this was so widely believed to be true that I didn't even bother to question it.
After all, younger women had (and still have) far lower rates of heart disease than men. And when women reach the menopause, their rate of heart disease explodes... does it not?
In reality it does not. Or, to be more accurate, the rise in the rate of coronary heart disease (CHD) in women represents a smooth accelerating upward curve which perfectly matches an increase in age, and is totally unaffected by the menopause. It lags behind the mortality curve of men by about ten years - for complex reasons that I am not going to discuss here.
I did not know this at the time. Like almost everyone else, I believed what I had been told, and I was interested in finding out how this protective mechanism actually worked.
At first I believed that finding the protective mechanism would be simple. Somewhere, I would find the major study proving that oestrogen and progesterone (UK spelling) had beneficial effects. However, after a frustrating and prolonged search (this was in a time long before the internet was available) I found no evidence at all. I came to understand that the reason why I could not find it was because it DID NOT EXIST.
There had been some work done on rabbits in the nineteen fifties, which seemed to show that rabbit female sex hormones had some beneficial effect on cholesterol levels in the blood. Some, other research showed that oestrogen lowered LDL and raised HDL, a bit, and that was pretty much all there was.
To my surprise (I would be completely unsurprised today), no-one had ever done a study on humans, and no controlled clinical trial existed. The entire area of research into this area resembled a vast barren desert, with a few tumbleweeds blowing in the wind.
Despite the non-existent foundations, by around the early nineteen sixties, the female sex hormone hypothesis was being presented in scientific conferences and medical papers in terms that brooked no argument on the matter.
It was just true, end of discussion. Somewhat later, in 1987 to be exact, a study was done which appeared to prove conclusively that hormone replacement therapy (HRT) was indeed highly protective against cardiovascular disease (CVD). A forty two per cent reduction in strokes and heart disease, no less (1).
No-one seemed particularly concerned that this was an uncontrolled study. By which I mean the researchers had not randomised two closely matched populations of women. One group to take HRT, the other not. Then see what happened to them over the next five or ten years. They just looked at women taking HRT, and those who didn't, and studied the difference in outcomes between these two populations.
As it turns out, women who took HRT - before it became widely promoted - were a different breed. They were extremely health conscious, more highly educated, and from higher social groups. They smoked less, they exercised more, and they had higher paying jobs. You name a confounding variable, and it varied.
Perhaps it could be argued, therefore, that this research was not actually comparing two populations that had the same heart disease risk to start with?
But by this time the bandwagon was heading off at great speed, and all doubters and their doubts about confounding variables were swept aside. By the early to mid-nineteen nineties the benefits of HRT became so widely accepted that menopausal women were now actively prescribed it to protect against heart disease and strokes. To do otherwise was considered virtual medical malpractice.
In order to confirm that everyone was now doing the right thing, a controlled study was set up to prove the benefits of taking HRT - the HERS study (The Heart and Estrogen / Progestin Replacement Study). Unfortunately, the HERS study proved the exact opposite to that which had been expected. It showed that HRT actually increased the risk of both heart disease and stroke. Not by a great amount, but enough to make it strongly statistically significant. It turned out that the 'fact' (female sex hormones protect against heart disease,) which was never based on any evidence in the first place, was proven to be untrue. Hold the front page, 'Unproven fact disproved'.
At the time this finding caused great shock and upset among various opinion leaders, some of whom flatly refused to accept the findings of the study. Some still do.
What really interested me about this whole sorry saga was not that the ‘ad-hoc' hypothesis itself was untrue. I became far more concerned with the broader question. Why are some ideas taken up so quickly, so widely, and with so little questioning, when there is no real evidence to support them? And why are other ideas rejected out of hand.
What are the drivers for this completely unscientific, and essentially emotional, behaviour? It turns out, as it would, that people have noted the existence of this phenomenon over the ages.
'When a man finds a conclusion agreeable, he accepts it without argument, but when he finds it disagreeable, he will bring against it all the forces of logic and reason.' Thucydides from 2,400 years ago.
More recently a UK surgeon called Wilfred Trotter concluded much the same thing about our inability to accept new ideas.
'The mind likes a strange idea as little as the body likes a strange protein and resists it with similar energy. It would not perhaps be too fanciful to say that a new idea is the most quickly acting antigen known to science.' Wilfred Trotter 1941.
Over the years, I have come across more and more examples of ‘acceptance without argument', and rapid, ‘antigen like' rejection. At first I thought it was somewhat ironic that medical scientists appear to be the worst at this type of instant acceptance - and dismissal. Are not scientists supposed to be objective seekers of truth? Should they not be willing to go wherever the facts lead them, however inconvenient? Surely scientists should be open-minded.
However, I have come to realise that this is not in the least ironic. In fact, it is probably to be expected. Scientists are just the same as normal mortals - only more so. However, to a far greater extent than most people, scientists become very closely associated with the ideas that they believe in.
In time their reputations and status come to depend on the hypotheses that they research, and lecture on. Can you imagine the impact of a leading climate change scientist, for example, declaring that they had changed their mind, and that man-made global warming is a myth? Just for starters, how do you think they would be treated by their peers?
The reality is that, once a scientist comes to believe that a hypothesis is correct e.g. heart disease is caused by eating saturated fat, which raises cholesterol levels, which causes thickening in arteries which leads to heart attacks and strokes - the ‘diet-heart/cholesterol hypothesis'. Once you believe this, and write articles on it, and gain awards for researching it, and make it your life's work. How easy is it to change?
Very difficult, would be the answer.
Dr. Malcolm Kendrick (MbChB MRCGP) M.D.
Dr. Kendrick has worked in family practice for twenty years.
He has specialized in heart disease and set up the online educational website for the European Society of Cardiology.
He is a peer-reviewer for the British Medical Journal.
How Ideas That Are Not True Become Facts - part 2
1: Bush TL et al. ‘Estrogen use and all-cause mortality. Preliminary results from the Lipid Research Clinical program follow up study.' JAMA 1983 Feb18;249(7):013-6