We’ve reported previously (here and here) on the erroneous conclusions drawn from the recent meat-and-mortality studies. This is a prime example of the kind of bias that can slip into a so-called “scientific” analysis of
foodstuffs. It’s something to be aware of whenever you read the words “a study has shown that….”
Something else to think about is where the money is. Sadly, science, money and bias are closely connected when it comes to studying the effects of diet on human health (even studies on the paleo diet would need to be reviewed carefully, although fewer studies exist on this).
Dr John Briffa provides a hat-trick of examples in some recent posts on his blog. The blog as a whole is worth keeping an eye on, because he does a consistently thorough job of critiquing the kind of sensationalistic reporting we’re seeing – from the media and from scientific institutes – in relation to nutritional studies.
Here’s his take on the meat-and-mortality studies: Red meat kills? It’s flagrant bias that’s killing me…., in which he notes:
This review is accompanied by an invited commentary from Dr Dean Ornish – a proponent of low-fat eating and a noted vegetarian . He concludes, in a word, that the answer to the question of whether red meat is bad for us is ‘yes’. But he can’t possibly do that on the basis of this type of evidence. Nowhere in his commentary does he refer to fact that associations do not prove causality – it’s simply not mentioned.
Dr Ornish does refer, however, to human studies in which relatively high-protein, low-carbohydrate diets have led to improvements in health markers such as weight, blood pressure and blood fat levels. In fact these human studies (and there are many) have been found to improve a range of health markers across the board. But Dr Ornish dismisses these studies by referring to one single study which was, wait for it, performed in mice bred to have a genetic glitch which makes them particularly susceptible to heart disease. How this applies to humans is anyone’s guess, and one thing we know for sure it’s not relevance to humans is tiny compared to studies done in actual, err, humans.
Dr Ornish sweeps aside ton of good evidence is swept aside in favour of a small amount of quite useless science instead. More bias? You decide.
In terms of money (in the science, money and bias equation) – here’s a good example of how profit can get in the way of honesty: Kellogg’s found guilty of misleading us about sugar, but it’s just the tip of the iceberg. In this article, Dr. Briffa exposes what happens when scientists representing the food industry get involved (you can just tell that’s never going to end well, can’t you?):
The adjudication refers several times to a consultation report held by the World Health Organization (WHO) and Food and Agriculture Organization (FAO) (both part of the United Nations) in 1998. This report large exonerated sugar in terms of its impact on things like obesity and heart disease. However, should we be so trusting of the findings and conclusions of this report?
Back in 2004, the BBC aired a documentary which focused on the politics of sugar. It highlighted how the consultation was essentially hijacked by ‘scientists’ representing the food industry, and how the consultation secretly funded the consultation. Scientists were warned against saying anything negative about sugar too.
Finally – and perhaps saddest of all – it seems that even charities set up to help the needy are not immune to the effects of science, money and bias. In another article, Dr. Briffa asks: What’s wrong with the dietary advice Diabetes UK dishes out to diabetics? His answer focuses on the fact that they describe several sugary cereals as being low on the glycaemic index (they’re not) and the types of food diabetics should eat (they aren’t). Also highlighted is the confounding factor created by the fact that the charity has several large corporate sponsors:
See here for a list of corporate sponsors of Diabetes UK. In amongst a whole raft of food and diet companies, you’ll see ‘Kelloggs’ (who make Sultana Bran and Special K) and ‘Shredded Wheat’. Could this explain why there highly disruptive foods get special mention from Diabetes UK and make their way into the ‘low-GI’ category even though they are anything but? I don’t know, but we should at least ask the question, I think.
Yes, we should ask the question – every time we read any study about food and health. Followers of the paleo diet aren’t immune to the thorny path of science, money and bias, either. To eat fish oil, or not? To limit PUFAs or avoid them altogether? Is sugar hellishly bad, or fairly benign? A quick trawl through the paleo diet blogosphere and you’ll find several proponents of each perspective, and they’ll all probably quote a study at you which “proves” that their point of view is right. You may also find that they change their mind as soon as they read a study which suggests the opposite.
There isn’t a simple solution to this state of affairs, of course. As for me, I’m sticking to the basics: eating a wide variety of real whole foods (which I prepare and measure in my kitchen, not a laboratory); resting and exercising effectively; and not believing everything I read….