Research funded by beverage industry is biased

— Confused by conflicting advice on nutrition and health? Then try ignoring any conclusions backed by the beverage industry. Corporate funding of research into non-alcoholic drinks biases findings in favour of manufacturers’ products, a new study has found.

Funding from the pharmaceutical industry is known to bias published research. David Ludwig of the Children’s Hospital in Boston, US, wondered whether the same is true for studies of nutrition, and focused on the highly-profitable beverage business. It is an industry rife with controversies, including disputes over obesity, diabetes and dental health.

Ludwig’s team examined 206 scientific papers on the health effects of soft drinks, fruit juice and milk, 111 of which declared their funding source. If anything, bias was even stronger than for research on drugs, with industry-backed papers being more than seven times as likely to produce a conclusion favouring a company’s product.

The reasons for the bias are unclear, but could include a failure to publish unfavourable findings, or a tendency of firms to back only studies that are likely to present their products in a positive light.

Above board

The American Beverage Association rejects the study. “This is yet another attack on industry by activists who demonstrate their own biases,” says its president, Susan Neely. She queries the exclusion of more than 300 articles from the team’s initial trawl of the literature. “By not disclosing the studies examined, it is entirely possible that articles were excluded simply because they did not prove the authors’ point,” Neely suggests.

However, Ludwig says that papers were excluded only if they failed to meet the pre-determined criteria for the study. He adds that the full list of the studies examined is available on request. “This is all above board and is standard practice,” Ludwig says.

Given the importance to public health, Ludwig believes governments should invest more in nutritional research, to counter industry bias. “It’s an extremely poor trade-off to save money on research and have to base nutritional policy on a flawed scientific database,” he argues.

Journal reference: PLoS Medicine (DOI: 10.1371/journal.pmed.0040005)

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