In previous blogs I have highlighted the sometimes malign influence industry can have on scientific research and the publications that publish it. In my post of 17th October 2006, for instance, I reported on one piece of research which found that studies sponsored by pharmaceutical companies were more than four times more likely to have favourable outcomes than studies with other sponsors . I have always had my suspicions that a similar potential for bias exists with regard to nutritional research, but never had the ‘evidence’ to prove it. Now, it seems, I have.
This week, the on-line journal PLoS (Public Library of Science) Medicine published a study which analysed the relationship between research funding and outcome in the area of nutrition . The researchers, based at the Children’s Hospital in Boston, USA, looked specifically at studies into soft drinks, milk and fruit juice. Part of the reason that they chose to look at research into these beverages related to their relevance to children’s health. Their highly profitable nature was another factor. Here’s what the researchers found:
- Of 206 relevant studies, 111 declared their source of funding
- Of this 111, more than half (53 per cent) were funded in full or in part by the food industry
- 52 studies had no funding from the food industry. Of these, 20 (38 per cent) produced unfavourable results
- 22 studies were funded entirely by the food industry. Of these, only 3 (13.6 per cent) produced unfavourable results
In studies which were interventional in nature (which usually meant giving a beverage to individuals to assess its effects), 37 per cent of non-industry-funded intervention studies showed evidence of adverse effects
In contrast 0 out of 16 (0 per cent) industry-funded intervention studies found evidence of adverse effect
Studies funded entirely by industry were more than 7 ½ times more likely to report favourable results than those which received no industry funding
Some of you may be wondering how it is possible for the overall findings of industry and non-industry funded research to vary so wildly. Are some researchers corruptible? Yes, despite the honest and trustworthy image scientists have engendered for themselves, the fact remains that some (though clearly not all) of them engage in some unethical and very unscientific practices. In fact, books have been written on this very subject [3,4]. In some cases, it seems that it is he who paid the piper that has called the tune.
However, not all researchers stoop so low. But that doesn’t mean they are not capable of designing experiments in a way that are likely to put the product being tested in a positive light. For instance, researchers may simply choose not look for potential adverse effects. And, obviously, if you don’t look, you don’t find.
Another tactic that researchers can employ is to design the study in such a way as to make it nigh-impossible for any adverse effect to be detected. One example that springs to mind is the industry-funded tests for the safety of the artificial sweetener aspartame. Some of these studies have tested the effects of aspartame administered as a slow-release capsule for just a single day. It doesn’t take a nutritional scientist to realise that such testing in no way reproduces the way in which aspartame is usually consumed in the real world (i.e. freely floating in foods and drinks consumed in the long term).
The other major ploy that the food industry and the researchers in its pay can use to skew reality is simply to publish positive findings and ‘bury’ unwanted ones. This practice, known as ‘publication bias’ is well known to exist in the area of pharmaceutical medicine. I reckon it’s safe to assume that publication bias goes on in the area of diet and nutrition too.
The PLoS study was accompanied by a commentary by Professor Martijn Katan of Vrije University in the Netherlands . In it, he concludes the Boston study raises serious concerns that some food industries may distort the scientific record on diet and health. He also issues a stark warning that: Such concerns affect nutrition science as a whole, if only because they threaten public confidence in nutrition research, and once that confidence is gone nutrition research becomes irrelevant.
This comment reminds me of just how often individuals say that, when it comes to nutritional information, it can be difficult to know who or what to believe. Now we know that much conflicting evidence in the area can come about as a result of the food industry’s relentless drive for profit, who can blame them.
1. Lexchin J, et al. Pharmaceutical industry sponsorship and research outcome and quality: systematic review. BMJ 2003 326(7400):1167-1170
2. Lesser LI, et al. (2007) Relationship between Funding Source and Conclusion among Nutrition-Related Scientific Articles. PLoS Med 4(1): e5 doi:10.1371/journal.pmed.0040005
3. Fraud and Misconduct in Biomedical Research Edtors Stephen Lock and Frank Wells. BMJ Books 1996
4. The Great Betrayal: Fraud in Science. Horace Freeland Judson. Harcourt 2004.
5. Katan MB. Katan MB (2007) Does Industry Sponsorship Undermine the Integrity of Nutrition Research? PLoS Med 4(1): e6 doi:10.1371/journal.pmed.0040006