Small sample sizes
The report, published in the British Medical Journal, highlighted the role of industry-sponsored research, small sample sizes, the links between suppliers and professional bodies and journals, and the apparent exclusion of ‘negative’ studies.
“This is reminiscent of the state of medical research around 20 years ago,” said Heneghan. “There has since been a clear shift towards evidence-based medicine.”
He added: “In the wake of various lawsuits, GlaxoSmithKline’s (GSK’s) Medical Division, for instance, now has far more of an open, transparent culture.”
GSK’s Lucozade Sport, Coca-Cola’s Powerade and PepsiCo’s Gatorade were among the drinks criticised.
Good quality studies
Head of Sports Science at the University of Bedfordshire, and himself a former GSK employee, Professor John Brewer said: “The biggest, most reputable sports nutrition manufacturers already understand that they have to conduct good quality studies to back up their claims.”
He agreed there were certain situations where water and lower-level calorie replacement were sufficient. “But there’s a huge amount of evidence that dehydration impairs performance, and a combination of fluids and carbohydrates supports it.”
In a statement, GSK pointed out that the science behind Lucozade Sport was supported by 85 peer-reviewed studies. It said the evidence for the benefits of carbohydrate-electrolyte drinks was “strong and has been independently studied and verified by the European Food Safety Authority (EFSA)”.
For its part, the Oxford team also found fault with EFSA’s assessment criteria. Of EFSA’s evolving assessment process, Heneghan said: “It reminds me of the way that the World Health Organisation has become more rigorous in its scrutiny of scientific submissions.”
A spokesman for EFSA pointed out that it had not accepted all claims relating to sports drinks. He added: “We review not only the evidence submitted by applicants, but all relevant scientific literature to reach our conclusions.”
The team from Oxford University’s Department of Primary Care Health Sciences criticised the research underpinning carbohydrate-based sports drinks. “We went into this impartially, and I was surprised by the low quality of much of the research,” reader in evidence-based medicine Carl Heneghan told Food Manufacture.
