• by Thom Forbes  @tforbes, September 18, 2014

A new study that finds that artificial sweeteners alter the bacteria in the gut and can actually raise blood sugar levels — increasing the risk of obesity and diabetes — is sure to cause a stir with those who like their coffee sweet sans sugar but both industry zealots and scientists on the sidelines caution that the human sample size of the study is exceedingly small and more research needs to be done. 

The paper, published online in Nature yesterday, “provides a big dollop of evidence in support of an emerging idea that artificial sweeteners are not directly bad for people (humans cannot even digest most of them). Rather, they may be bad for the zillions of microbes that live in people’s guts—and this, in turn, may be bad for their human hosts,” the Economistexplains.

“Dr. Eran Elinav of the Weizmann Institute of Science's Department of Immunology, who led this research together with Prof. Eran Segal of the Department of Computer Science and Applied Mathematics, says that the widespread use of artificial sweeteners in drinks and food, among other things, may be contributing to the obesity and diabetes epidemic that is sweeping much of the world,” Science Dailypoints out.

That could be devastating news, of course, for the likes of Diet Coke, which an Economistarticle calls “one of science’s great miracles” for its ability to sweeten flavored carbonated water with “a pair of chemicals that are far sweeter than ordinary sugar, but which provide the body with no energy at all.” 

Substitute the word calorie for energy and you see the appeal of substances such as saccharin, sucralose, aspartame and acesulfame-K to those who are prone to ingesting more energy than they burn through physical activity.

The Financial Times’ Clive Cookson reports that research firm Mintel “estimates that 5.5% of all food and drink products launched last year contained at least one sweetener, compared with 3.5% in 2009 — an increase it attributes to the “'demonization of sugar'.”

“Based on existing evidence, guidelines jointly published in 2012 by the American Heart Association and the American Diabetes Association noted that artificial sweeteners ‘when used judiciously … could facilitate reductions in added sugar’ and thus influence weight loss,” writes Gautam Naik in the Wall Street Journal.

“The new Nature study marks a significant advance because it brings together two separate areas of research — the role of sweeteners in raising blood sugar levels, and the complex workings of the vast colonies of bacteria that inhabit the gut,” Naik continues. “Individuals can have differing bacterial colonies in their gut, meaning people respond differently to what they consume.”

The story, as you might expect, is making headlines around the world — along with requisite cautions about reading too much into it. 

“Independent commentators praised the work for its innovation, but warned against overreaction,” according to a piece in the [South Africa] Times. “The human trial involved just seven people over a week, and wider and longer trials are needed to draw any firm conclusion, they said.”

Among those cited by the Times is John Menzies of the Centre for Integrative Physiology at the University of Edinburgh in Scotland, who said: “Human diets are complex, consisting of many foods, the consumption of which can vary in amounts, and over time.” 

Most of the work, in fact, was done with mice.

“The study suffers from small sample sizes, unrealistic sweetener applications, and a dependence largely on rodent research,” the Calorie Control Council, which represents the low-calorie and diet food and beverage industry, said in the summary of its multi-point retort. “Findings should be interpreted with caution.”

“Dr. Frank Hu, a professor of nutrition and immunology at the Harvard School of Public Health who did not take part in the study, called it interesting but far from conclusive and added that given the number of participants, ‘I think the validity of the human study is questionable,’” reports Kenneth Chang in the New York Times.

Moderation, as always, is likely to be the watchword until more conclusive results are established.

“I think I will recommend that people not drink more than one or two cans [of diet soda] a day,” George King, chief scientific officer at the Joslin Diabetes Center in Boston and author of the forthcoming The Diabetes Reset, tells Karen Weintraub in USA Today. 

“I think this issue is far from being resolved,” Elinav, who led the study, offered. But he told reporters on a telephone news conference Tuesday that “given the surprising result we got in our study, I made a decision to stop using” the artificial sweeteners he said he’d been using “extensively” in his coffee “thinking that they were at least not harmful and perhaps even beneficial.”

And more than a few consumers are sipping their own coffees this morning wondering what’s coming next to confuse their best efforts to eat and drink well.