October 24, 2017

Think dark chocolate is the healthy Halloween choice? We've got bad news.

Daily Briefing

    Editor's note: This popular story from the Daily Briefing's archives was republished on Oct. 31, 2019.

    "Big chocolate" has waged a decades-long, multi-million dollar campaign that relied on industry-funded nutrition science to take dark chocolate from an indulgent snack to a health superfood akin to avocados and blueberries, Julia Belluz reports for Vox.

    Understand the wellness spectrum—and promote healthy habits at work

    While industry funded research into food is not uncommon, Belluz writes, "Big Chocolate's foray into nutrition research is a great case study in how industry can steer the scientific agenda—and some of the best minds in academia—toward studies that will ultimately benefit their bottom line, and not necessarily public health."

    To investigate the issue, researchers at Vox reviewed 100 original cocoa studies funded or supported by Mars. According to Vox, the studies "overwhelmingly drew glowing conclusions about cocoa and chocolate" and reported a range of health benefits. Those findings, coupled with widespread—and often misleading—media coverage has "yielded a clear shift in the public perception of the products," Belluz writes. In fact, even as candy sales overall have been declining, research by Euromonitor International shows that chocolate sales in the United States have increased from $14.2 billion in 2007 to $18.9 billion in 2017.

    However, despite the chocolate industry's push, cocoa has not been proven to hold any long-term health benefits, Belluz reports—and the fat and sugar included in most dark chocolate bars quickly negate any potential health perks that might exist.  

    Inside one company's research push

    Mars in 1982 launched the Mars Center for Cocoa Health Science, which focuses in part on the biology of cocoa and its effects on human health. Since the center was established, Mars' scientific research arm, Mars Symbioscience, has "flooded journals with more than 140 peer-reviewed scientific papers," Belluz writes.

    In recent years, Mars has narrowed its focus to research into flavanols, micronutrients found in cocoa and many other plants that have antioxidant properties—and could explain why eating fruits and vegetables is so beneficial, Belluz reports.

    For instance, according to Belluz, Mars-sponsored research includes studies showing that regularly eating cocoa flavanols could improve mood and cognitive performance; that dark chocolate boosts blood flow; that cocoa might be beneficial for immune disorders; and that cocoa powder and dark chocolate can have a "favorable effect" on cardiovascular disease. In fact, almost all of the Mars-backed studies—which have involved researchers from Harvard University, Georgetown University, and universities in other countries—have led to positive conclusions about chocolate or cocoa, Belluz reports.

    Misleading research, media coverage

    But experts say the overwhelming positive findings indicate that the research could be biased. For instance, Richard Bazinet, a University of Toronto nutrition researcher, said, "By spending a lot of money on one topic but not another, (it) can sort of create a publication bias."

    In other words, according to Belluz, companies are steering the research into favorable findings by selectively funding studies that support the companies' research agenda—and in turn, that can divert money into research that would otherwise explore more health-focused objectives. 

    Further, Belluz writes the media exacerbates this bias by frequently misrepresenting the findings. For instance, one Mars-backed study using specific cognitive ability tests concluded that flavanols may improve function in the part of the brain where age-related deterioration is associated with memory decline. However, the nuance of the findings were obfuscated in the media, with the New York Times suggesting chocolate was a memory aid.

    Lead researcher Adam Brickman of Columbia University said, "We (were) very careful about not referring to (the cocoa flavanols) as chocolate." He added, "Nothing was more upsetting than seeing the headlines along the lines of 'eating chocolate cures Alzheimer's,' which was not what our study was about."

    What the research really shows

    In its review, Vox found that the most prominent and best-studied health benefit of cocoa relates to blood pressure: Evidence suggests cocoa flavanols can boost the synthesis of nitric oxide in the blood vessels, which increases blood flow and lowers blood pressure. A Cochrane review found that flavanol-rich chocolate and cocoa products "cause a small (2 mmHg) blood pressure-lowering effect in mainly healthy adults in the short term."

    That said, while cocoa beans are high in flavanols, Belluz writes the processing involved in making dark chocolate can destroy the nutrient, meaning most candy bars aren't a good source of them. In addition, most research into the potential healthfulness of cocoa doesn't address the fact that people are most likely to consume cocoa in the form of a sugary candy bar.

    As Michael Moss, author of "Salt Sugar Fat," put it, "Dark chocolate probably has some beneficial properties to it, but generally you have to eat so much of it to get any benefit that it's kind of daunting, or something else in the product counteracts the benefits. In the case of chocolate, it's probably going to be sugar."

    For its part, Mars told Vox, "We are always clear that chocolate is a treat, not a snack, food, or meal replacement, and market our products accordingly." It added, "We do not translate or communicate the outcomes of our cocoa flavanol research program in the context of chocolate" (Belluz, Vox, 10/18).

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