As part of my nutritional studies, I had to do a lot of reading and research. I read the course materials, but I also read outside of the course. One of the books I read that significantly transformed my perspective on nutritional science was The Great Cholesterol Con, by Dr Malcolm Kendrick.
I’ve talked a lot about how Dr. Kendrick has disproved the lipid hypothesis and believes that stress plays a more important role in heart disease. However, I have not yet described what he has said regarding mainstream scientists’ shoddy science, particularly their use of ad-hoc hypotheses.
Why are we talking about ad-hoc hypotheses? Are they even relevant?
They are very relevant. They are the main reason why the scientific reporting in the media is so conflicted. You know, one day they tell you that a group of scientists has found that drinking red wine is good for your health and the next day they tell you another group has found it isn’t… Who the hell are you supposed to believe?
OK, you’ve got my attention.
What is an ad-hoc hypothesis?
An ad-hoc hypothesis is a new hypothesis that a scientist adds to his original theory in order to save it from being dismissed because of an experiment that seems to show that his original theory is invalid.
A good example of an ad-hoc hypothesis that most people will be able to appreciate is common in the field of extra-sensory perception (ESP). Extra-sensory perception experiments are notoriously difficult to reproduce in front of an audience that is skeptical about ESP. The response of the ESP researchers has been to formulate an ad-hoc hypothesis. This ad-hoc hypothesis is that the negative thoughts of the skeptical audience interferes with their readings!
You can see hopefully how the use of ad-hoc hypotheses can keep a dead theory alive in zombie form for decades. Just like a dead parrot, the only way you can keep the original theory upstanding is by the judicious use of
nails ad-hoc hypotheses.
OK, stop being funny. What’s this dead parrot theory you are talking about?
The dead parrot theory is the lipid hypothesis of heart disease, which suggests that heart disease is caused by eating more saturated fat. The more saturated fat you eat, apparently, the more at risk of heart disease you are.
If you were a sane person, you might then consider whether the evidence suggests this to be correct. Let’s have a look. Oh drat! It looks like the French eat lots more saturated fat than we do but their risk of heart disease seems to be much lower.
At this point, a sane person would conclude that the hypothesis was not upheld and that we should formulate a new one. Perhaps we could look at stress? I bet the French are a lot less stressed than we are. I mean, look at that 35-hour legal limit on the working week. If that doesn’t give you a clear idea of their priorities then I don’t know what will.
However, someone determined to nail the
parrot theory back on the perch would use an ad-hoc hypothesis. Perhaps they might invent a concept called the “French Paradox” and then look for nutritional basis for this paradox with which to create an hypothesis. Perhaps they might end up with the old cliches that French people eat more garlic and drink plenty of red wine.
They did use those old chestnuts to create an ad-hoc hypothesis? The scoundrels!
So what does Dr Kendrick say about The French Paradox?
Dr Kendrick has looked at the research into the claimed protective powers of the French Paradox ad-hoc hypothesis.
He has reviewed studies relating to the impact of garlic and red wine on heart disease and he has concluded that there is no evidence that any of these are protective against heart disease. He asserts that the only studies that are even vaguely suggestive of some small impact have been done by people either funded by food manufacturers or by the food manufacturers themselves. He suggests that the only reason that we even consider them to be a possible source of health benefits is because of the erroneous French Paradox.
But is it as simple as that? Let’s take a look…
Garlic is supposed to improve our risk of heart disease.
However, a meta-analysis by Silagy that included direct contact with food manufacturers was inconclusive and when Silagy went away and did his own controlled experiment to see what the real picture was, he was surprised to find that garlic didn’t have any effect.
And Berthold, Sudhop and von Bergmann found exactly the same thing in their randomised and controlled trial.
Conclusion? Garlic has no effect on heart disease.
We all hear in the media how red wine is almost guaranteed to improve our risk of heart disease. And yet the media is confused about whether red wine is fundamentally good for you. A perfect example is this article in the Telegraph, in which scientists are at odds over the recommendations of a recent study. Is it a bottle of wine? Is it a glass? How the hell does it work anyway?
Dr Kendrick is convinced that we shouldn’t even be thinking in this way. He thinks that our obsession with red wine being protective of heart disease is a blind alley. He thinks we are looking at red wine purely because of the erroneous ad-hoc hypothesis of the French Paradox.
The American Heart Association, while never knowingly up-to-date, makes it clear that the jury is definitely out, saying:
Over the past several decades, many studies have been published in science journals about how drinking alcohol may be associated with reduced mortality due to heart disease in some populations. Some researchers have suggested that the benefit may be due to wine, especially red wine. Others are examining the potential benefits of components in red wine such as flavonoids and other antioxidants in reducing heart disease risk.
The linkage reported in many of these studies may be due to other lifestyle factors rather than alcohol… No direct comparison trials have been done to determine the specific effect of wine or other alcohol on the risk of developing heart disease or stroke.
That seems pretty definitive to me.
Moving away from Dr Kendrick’s hardline scepticism and the dry-as-a-bone humourless stand of the AHA to recent research, this review of recent research was cautiously optimistic about the benefits of red wine for the prevention of heart disease. However, there are enough comments in the review to suggest to me that they are not completely sure whether the small effect is due to the effect of antioxidants, polyphenols or any other small and interesting micronutrients or the relaxing effect of the alcohol causing a reduction in stress. Are you spotting a trend here?
I still don’t know for sure but let me sum up where my head is at: based on what Dr Kendrick has said, I think people are studying red wine because of the French Paradox and because it could turn out to be the panacea of a foodstuff that is both enjoyable and healthy. And it is a psychologically observable phenomenon that people do tend to find what they are looking for, even when they are scientists.
However, even if there are some small heart disease benefits of red wine (and I suspect that the majority of any effect would occur via a stress reduction), I think they are likely to be outweighed by the damage caused by alcohol to other areas of my health. For more on why alcohol is really bad for you (and me).