Researchers Find Bias in Nutrition Studies A new study, co-authored by Harvard researchers and analysts from the Center for Science in the Public Interest, suggests there's a systematic bias in nutrition studies funded by food companies.

Researchers Find Bias in Nutrition Studies

Researchers Find Bias in Nutrition Studies

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A new study, co-authored by Harvard researchers and analysts from the Center for Science in the Public Interest, suggests there's a systematic bias in nutrition studies funded by food companies.


For the first time researchers at Children's Hospital in Boston have documented widespread bias in nutrition studies funded with industry money. The study questions whether the science behind nutrition recommendations is solid.

NPR's Allison Aubrey reports.

ALLISON AUBREY: Emerging evidence of bias in nutrition studies echoes what's already had been documented in pharmaceutical research. That is when a drug company pays for a research study; the results are likely to be favorable to the company.

To determine whether this same influence holds up on the field of nutrition research, David Ludwig, who directs the clinical weight loss program at Children's Hospital in Boston, analyzed 206 studies published between 1999 and 2003.

Dr. DAVID LUDWIG (Director, Obesity Program, Children's Hospital in Boston): We focused on milk, fruit juices, and soft drinks, because these beverages are highly profitable and heavily advertised to children.

AUBREY: To carry out the study objectively, Ludwig had one group of investigators analyze the nutrition studies' scientific conclusions without knowing anything about their financial sponsorship. A second group looked up the funding of the studies without knowing anything about the conclusions.

Mr. LUDWIG: We found out that when a food company pays for a scientific article, the results are about eight times more likely to be favorable to the company's financial interests than when a study is funded independently.

AUBREY: Since more than half of the nutrition studies did have some industry funding, Ludwig says the evidence of systematic bias is striking.

Mr. LUDWIG: Conflicts of interests in pharmaceutical research could affect the millions of people taking medicines. But conflicts of interests in nutrition could affect everyone because ultimately everybody eats.

AUBREY: What we eat can be heavily influenced by advertising and public health messages, who have interred the government-backed advice to eat more fruits, or the dairy industry's promotion that milk builds better bones. Kelly Brownell directs the Rudd Center for Food Policy and Obesity at Yale University.

Mr. KELLY BROWNELL (Director, Rudd Center for Food Policy and Obesity, Yale University): Both the dairy and the soft drink industries are notorious for giving investigators money to do studies that typically find things favorable to the industry. And if the studies are biased, which they appear to be, we're not getting the correct picture.

AUBREY: Exactly how the picture might be wrong isn't clear. The study was not designed to evaluate the merits or shortcomings of any individual study, rather it suggests in the aggregate, that researchers seemed to be loyal to the hands that feed them.

Greg Miller works for the dairy industry. He's vice president of Science and Innovation at the National Dairy Council, and he argues, the new analysis is terribly flawed.

Mr. GREG MILLER (Vice President, Science and Innovation, National Dairy Council): We take great pride in the research that we fund, making sure that it is scientifically sound, adheres to good scientific methodologies and it gets published in some of the best scientific journals in the U.S.

AUBREY: Getting published and peer reviewed scientific journals is indeed an indicator that a study is sound, but it's no guarantee that researchers or their conclusions are free of bias. Kelly Brownell.

Mr. BROWNELL: I don't believe that researchers are intentionally tainting their data, but I do believe that unintentional biases enter in in the way studies are designed and interpreted.

AUBREY: Manipulations can be subtle, such as framing the questions in a way that makes the results more favorable. Or in other cases, studies with negative conclusions may never be published, so next time you'll hear a piece of advice about what you should or shouldn't be eating or drinking, consider the source. If it's a new study, who paid for it?

Allison Aubrey, NPR News, Washington.

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