Junk Science or Junk Food? Experts Debate Sugar Guidelines

Marcia Frellick

December 19, 2016

Guidelines on dietary sugar published over the past 20 years do not meet the criteria for trustworthy recommendations for reasons that include low-quality evidence and inconsistent advice, say the authors of a new review published today in the Annals of Internal Medicine.

Jennifer Erickson, RD, from the University of Minnesota in St Paul, and colleagues say their literature search unturned nine sets of guidelines issued between 1995 and 2016 that offered 12 recommendations, seven of which were qualitative and five of which were quantitative, that ranged from advising that less than 5% to less than 25% of total calories should be from "nonintrinsic" sugars per day.

But all the guidelines scored poorly when measured by the Appraisal of Guidelines for Research and Evaluation, 2nd edition (AGREE II), say Ms Erickson and colleagues, "specifically in rigor of development, applicability, and editorial independence."

Terminology differed among the guidelines, with some referring to "free sugars" (which include sugars found in fruit, honey, or syrup as well as sugars added to food and drinks) or "added sugars" or recommendations for sugary beverages.

The authors conclude that "at present, there seems to be no reliable evidence indicating that any of the recommended daily caloric thresholds for sugar intake are strongly associated with negative health effects."

Funders Represent Food and Beverage Giants

But before accepting these authors' conclusions, two editorialists say, it's important to note the funding source for the review: the North American branch of the International Life Sciences Institute (ILSI).

"ILSI North America is a trade group representing the Coca-Cola Company, Dr Pepper Snapple Group, the Hershey Company, Mars, Nestlé, and PepsiCo, among others," they write.

Dean Schillinger, MD, University of California San Francisco (UCSF) division of general internal medicine at Zuckerberg San Francisco General Hospital and UCSF Center for Vulnerable Populations, and Cristin Kearns, DDS, at UCSF Institute for Health Policy Studies and UCSF School of Dentistry, add that ILSI has a history of opposing quantitative sugar limits.

Ms Erickson and team do note that the funding source is a limitation of their work but stress that they "wrote the protocol and conducted the study independent of the funding body."

The editorialists also take issue with some of the premises of the review. One is that the authors cite inconsistency among recommendations made between 1995 and 2016 as a basis for needing a new review of guidelines.

"One would expect recommendations spanning more than 2 decades to evolve as scientific knowledge evolved," Dr Schillinger and Kearns write.

The Politicization of Science

Ms Erickson and team also call into question the editorial independence of the Dietary Guidelines for Americans (DGA), which put the limit of sugars at less than 10% of calories, saying the funding source was "unclear."

"This assessment is curious," the editorialists counter. "The review's appendix acknowledges that the DGA is federally sponsored and that advisory committee members were thoroughly vetted for conflicts per federal rules."

And Drs Schillinger and Kearns say using the AGREE II measure is problematic to assess guideline quality because it is designed for clinical-practice guidelines in treating illness.

Dietary guidelines are meant to gauge risk of consumption at a population level, they write, "not to evaluate interventions to reduce consumption."

The authors, using that tool, downgraded the trustworthiness of guidelines.

The editorialists acknowledge analysis of guidelines is welcome but call the study by Ms Erickson et al "politicization of science."

As to what can be done to help the public get information on sugar's effect on health without potential bias in research, the editorialists suggest a change in publication policy.

They note, for example, that leading journal editors have refused to publish articles funded by the tobacco industry and suggest the same stance is taken with regard to the food and beverage industry.

"High-quality journals could refrain from publishing studies on health effects of added sugars funded by entities with commercial interests in the outcome," they suggest.

And policy makers — when confronted with claims that sugar guidelines are based on "junk science" — should consider whether "junk food" was the source, they conclude.

This project was funded by the Technical Committee on Dietary Carbohydrates of ILSI North America. The authors wrote the protocol and conducted the study independently from ILSI. Ms Erickson reports no relevant financial relationships. Disclosures for the coauthors are listed on the journal website. Disclosures for the editorialists can also be found on the journal website.

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Ann Intern Med. Published online December 19, 2016. Abstract, Editorial

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