Wrigley’s self-serving oral health plan gets free pass from news media

Kathlyn Stone is as associate editor with HealthNewsReview.org and a regular blog contributor.


gum chewing adolescent

Simply chew sugar-free gum after eating or drinking, and you’ll save yourself and the UK a lot of painful dental expenses. Or so says Wrigley, the chewing gum company, in a news release headlined “Chewing sugar free gum could save the NHS £8.2 million a year.”

Unfortunately, the British media took the bait. The Telegraph, Daily Mail, Sky, Sun and other news media all reported the finding using the same language as in the release. None included outside experts.

It’s a prime example of what happens when industry–with the help of academic researchers and the news media–collaborate to influence health policy.

“New health economic research published in the British Dental Journal demonstrates that the NHS could save up to £2.8m on dental treatments per year if all 12-year-olds across the UK were to chew one additional piece of sugar free gum per day,” according to the Wrigley’s news release funneled through the university.

No independent voice, no disclosure

In the Telegraph story, Professor Liz Kay, of Peninsula Dental School is quoted suggesting the cost savings could be even larger if sugar-free gum chewing were adopted by the entire adult population. “Crucially, whilst these figures are significant, they refer only to cost reductions for treating 12-year-olds in the UK; if this model was to be applied to the whole population then there is a real potential to create substantial NHS savings,” said Kay.

But is it reasonable to extrapolate these results from 12-year-olds to the entire adult population? What if the findings don’t hold up? Wouldn’t it be a good idea to test the assumption before speculating how substantial the savings would be for NHS?

Unfortunately, the story doesn’t disclose that Kay also is one of the study authors who received Wrigley funding. The study, published in The British Dental Journal, part of the Nature Publishing Group, includes this disclosure: “This study and writing support for the manuscript were funded by Wrigley Oral Healthcare Programme.”

By failing to consult experts not directly tied to the study (or the Wrigley company), the news media missed the opportunity to discuss some important weaknesses of the study.

A big limitation was that none of the data had any basis in the UK population.

“No UK clinical trials of SFG [sugar free gum] could be identified and therefore evidence was taken from a study based in Lithuania that was undertaken in 1994 to 1997,” the study states. Meaning, the information was extrapolated from a Lithuanian epidemiological and applied to England’s population and economy.

Other crucial details? The study also states, “Caries reductions achieved with SFG are likely proportional to the baseline prevalence and therefore the risk reduction will be a function of both baseline prevalence and chewing frequency.” This acknowledges that one’s predilection for tooth decay could have as much impact on decay as gum chewing.

The study continues, “The sensitivity analysis undertaken as part of this study demonstrated that cost savings would not be as substantial as those estimated in the base case analysis, but would nevertheless still be generated even if only a 1% reduction in caries were achieved.” This suggests that if there were cost savings, they could be quite a lot less than the £8.2 million a year claimed in the headline.

Wrigley has done this before

In 2009, Baylor College of Medicine in Houston, Texas, conducted a Wrigley-funded study that found gum chewing leads to higher math scores among teens. In that study, researchers recruited 100 charter school kids, all 14 years old. Half of the students were allowed to chew gum in math class for 14 weeks and the other half wasn’t. At the end of the study, the gum-chewing group showed a 3 percent increase in standardized math scores compared to the control group.

Again the news media couldn’t resist that one. And again, no second sources in the bulk of the coverage and no mention of the many potential biases inherent in such a study:

gum media

The point of all this, which we can’t underscore enough, is how important it is for journalists to think critically about the studies they’re covering and to get some outside perspective on the findings. Our list of review criteria and our toolkit provide excellent resources for analyzing health studies more thoughtfully.

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Comments (2)

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Frieda Pickett

March 14, 2016 at 2:53 pm

Sugar-free gum usually has a sugar alcohol as the ingredient to sweeten the taste. These include xylitol, mannitol or sorbitol (or a combination of these). Several systematic reviews of best evidence reveal a modest reduction in dental decay. A quote from an article discussing the evidence base for anticaries agents says “Sugar alcohols (eg, sorbitol, mannitol, and xylitol) are sweeteners that are metabolized by bacteria at a much slower rate than glucose or sucrose, or not at all.17 Xylitol is a five-carbon sugar alcohol known to reduce the incidence of caries by decreasing plaque formation, limiting bacterial adherence, reducing enamel demineralization, and inhibiting mutans streptococci—the bacteria most implicated in the caries process.20 Based on numerous clinical trials, the American Academy of Pediatric Dentistry recommends the use of xylitol in patients at moderate to high caries risk.21 According to the ADA Council on Scientific Affairs, supervised consumption of xylitol chewing gum in children age 5 to 16 for 10 minutes to 20 minutes after meals marginally reduces the incidence of caries.22 ” The science supports use of any of the sugar alcohols in chewing gum to reduce dental decay. In 2011 the American Dental Assn gathered an expert panel to perform a systematic review of evidence for nonfluoride agents and degree of caries reduction and recommended, on weak evidence for children 5+ years, chewing sugarless gum (https://carifree.com/media/wysiwyg/pdf/EvidenceBasedResearch/J_Am_Dent_Assoc-2011-Rethman-1065-71.pdf). The same SR recommended on “expert opinion” that adults could use this form of gum to reduce dental decay.

Kathlyn Stone

March 15, 2016 at 11:59 am

Thank you, Frieda Pickett, for your compact review of the literature on sugar-free gum and dental cavities. You helpfully underline the point of the blog post that there are strengths and weaknesses among the studies and that’s something news media might have covered had they sought an independent source.