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Latest Review on Sugar Intake Comes Under Fire
Dietary sugar is
making headlines again following the publication of an industry-funded
review examining health guidelines on sugar intake and the development
of a heated debate surrounding the findings. On average, adults in the
United States consume a total of 22 teaspoons of sugar per day, mainly
from sources such as soft drinks, candy, cookies, and fruit drinks.
That’s more than twice the American Heart Association’s recommended
daily intake and part of an increasing global trend in sugar intake.
In the midst of calls by the World Health Organization (WHO), the FDA
and Public Health England to reduce sugar intake, the new systematic
review questions the scientific basis underlying these guidelines,
arguing that they are based on weak evidence and do not meet the
criteria for trustworthy recommendations.
Systematic Review of Current Guidelines
In the review published in the Annals of Internal
Medicine last month, the authors, Jennifer Erikson,
Behnam Sadeghirad, Lyubov Lytvyn, Joanne Slavin and
Bradley C. Johnston, examined nine sugar-intake guidelines
(both quantitative and qualitative) from around the globe, including
those from the WHO, United States Department of Agriculture, and the
Institute of Medicine. The team of researchers then collected and
evaluated the evidence used to formulate each recommendation. While
they found that these public health organizations were in general
agreement suggesting that the consumption of free sugars should be
reduced in the diet, the authors of the review rated the quality of
evidence linking sugar with health outcomes as low to very low and
argue that current guidelines need to be revisited and improved.
Although the authors believe that the public should be given guidance
on dietary sugar consumption, they conclude, “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
health effects.”
The
Backlash and Controversy
This conclusion has now come under heavy fire from
multiple angles, as scientists and public health officials weigh in.
One of the main criticisms is aimed at the industry funding behind the
research. The review was sponsored by the International Life Sciences
Institute (ILSI) which in turn is funded by many big-name food
manufacturers like Coca-Cola, General Mills, Hershey’s, and Kraft. In
addition, one of the authors is on the scientific advisory board of
one of the world’s largest producers of high-fructose corn syrup.
Critics Respond
Critics such as Dean Schillinger, a physician at
the University of California, San Francisco and co-author of an
accompanying editorial published in the same issue, think that the
paper is politicizing the science and that nearly all the scientific
evidence shows a clear cause-and-effect relationship of sugar
consumption to obesity and type-2 diabetes. Barry Popkin, a
nutrition professor at the University of North Carolina at Chapel Hill
agrees, and told the New York Times that Erikson et al.
“ignored the hundreds of randomized controlled trials” documenting the
adverse effects of excess sugar intake, adding that he was astounded
that the paper made it through peer-review. Marion Nestle, a
nutrition professor at New York University, says in a NYT
interview that “This comes right out of the tobacco industry’s
playbook…” calling the paper a “shameful” attempt by the food and
beverage industry to undermine the scientific consensus on limiting
sugar.
Their fear is that this latest review could be used to
cast doubt among the public and weaken the public health efforts to
combat diseases linked to sugar consumption. ArsTechnica went so far
as to call the sugar industry’s attempts “gas-lighting” and
Schillinger also compared the industry’s efforts to what Big Tobacco
did to cover up the effects of secondhand smoking on health. This
current controversy comes on the heels of the recent report published
by Cristin Kearns et al. uncovering the sugar industry’s role
in manipulating dietary policy since the 1950’s and ‘60’s, whereby
they downplayed the link between dietary sugar and coronary heart
disease (
covered in the September
issue of EpiMonitor
).
Interestingly, the Associated Press (AP) reported that
the Mars corporation (also affiliated with ILSI) bucked the general
industry stance and also denounced the recent paper, saying that it
undermined the science and threatened the reputation of
industry-funded science. Somewhat alarmingly, the AP also reported
that there was an issue with the original disclosure statement on the
manuscript which claimed that the protocol and study were conducted
independently; however, after the AP found evidence that the group had
input on the proposal, the disclosure was later corrected.
In Defense of the Review
Christine Laine,
Editor-in-Chief of the Annals of Internal Medicine, said in a
written statement to the press that they decided to publish the review
along with a critical editorial because of its “great interest” to
their audience. In ILSI’s defense, Eric Hentges (Executive
Director) states that the paper focuses on the quality of the methods
and evidence used to determine the current recommendations and “is not
an industry attempt to undermine the science”. One of the study’s lead
authors Bradley Johnston, clinical epidemiologist at the Hospital for
Sick Children in Toronto, concludes that current guidelines which were
reviewed are simply “not trustworthy” due to the large amount of
uncertainty in the underlying science used to derive them. Johnston
told the NYT, “We hope that the results from this review can be used
to promote improvement in the development of trustworthy guidelines on
sugar intake”, adding that the review “should not be used to justify
higher intake of sugary foods and beverages.”
Details of how the
team evaluated each of the recommendations and guidelines is available
in the Erickson et al. manuscript:
https://tinyurl.com/jlul2xa
The accompanying
editorial can be seen here:
https://tinyurl.com/gmxrkhy
Recent EpiMonitor
coverage of dietary sugar debate:
https://tinyurl.com/gwz9eeg
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