A new meta-analysis, of 60 studies that were financed by the soft drink industry, uncovers striking evidence of bias in the vast majority of the studies.
If what this new research suggests is true, this could mean that the evidence in trials that showed no link between soda drinks and the risk of obesity or type 2 diabetes has been largely misrepresented.
The extent of the likely harm that it has caused to public health is unprecedented in modern medical history.
According to researchers at the University of California, 26 out of 60 trials published between 2001 and 2016, concluding that there was no causal relationship between soft drinks and the rise in metabolic disorders, were industry-funded.
Comparatively, only one of the 34 other studies that did show an association between their product and the alarming upward trend in development of these chronic diseases, was industry-backed.
This adds to a growing literature that industry studies are for the most part inherently biased in their assessments.
Looking at just the independent studies, it becomes clear that a high sugar consumption from soft drinks contributes to rising rates of diabetes and obesity.
Earlier this month, a study in the European Journal of Endocrinology has found that drinking more than two soft drinks (including those artificially sweetened) a day doubles the risk of developing type 2 diabetes and LADA.
Biases in industry-funded research persist due to the way the studies are designed, but also because of how the data is analysed and reported.
Twenty to 25 years ago, all of the main medical journals published wholly objective editorials that looked at the balance of data, but there has been a shift in the way they behave today.
Some of these reputable journals are often on a campaign to sell copy and therefore liable to be biasing their content towards the story that they are trying to build up.
Without reliable gatekeepers in place, the soft drink industry has had all the leisure to unload questionable studies that create a bit of controversy and advance their business interests.
The current study highlights that most research funded by soda giants doesn’t adhere to the highest standards of integrity for scientific inquiry, with problems including poor choice of comparators, focusing on a particular outcome and failing to define cofactors.
In addition to that, current bias rating systems, like the USDA Dietary Guidelines Advisory Committee Assessment Tool, do not include funding as a source of bias in itself.
Overall, there should be much more transparency than currently exists with complete trial data available for independent scrutiny on the effects of high sugar intake, which is slowly becoming as big a public health war as tobacco.
