BETA
This is a BETA experience. You may opt-out by clicking here

More From Forbes

Edit Story

Could Artificial Sweeteners Be Contributing To The Obesity Epidemic?

Following
This article is more than 9 years old.

It’s been unclear whether artificial sweeteners actually help the obesity crisis – some evidence has shown that they may do just the opposite. One reason is that already overweight people may be more likely to use artificial sweeteners. Or it could be that artificially sweetened drinks give us the green light to consume more food in general, since we’re “saving” so many calories in our drinks. But now, a new study in Nature adds a compelling piece to puzzle: Artificial sweeteners appear to lead to higher blood sugar, in both mice and men. And this isn’t because the chemicals interfere with the function of any of our organs: They seem to interfere with the friendly bacteria in our gut.

Here's how they arrived at this. In one of the studies, the team had mice drink water with one of three sweeteners – saccharin, sucralose and aspartame – and found their blood sugar levels rose significantly, in comparison to those who drank either plain water or sugar water. Even more telling was when the researchers transplanted the gut bacteria of the mice who’d consumed these sweeteners into mice who were bred to have no gut bacteria at all. Amazingly, the recipient mice also developed glucose intolerance. When the researchers analyzed the distribution of the bacteria, they found abundances of bacteria that have known links to obesity and diabetes.

But if you’re not convinced, because, after all, these were mice, read on. The researchers also looked at human subjects – regular consumers of artificial sweeteners had measurably different gut bacteria than non-consumers. To push into this, the team had the people who rarely or never consumed artificial sweeteners do exactly this for a week. Within that period, half of the human participants developed some glucose intolerance, and had proliferations in certain gut microbes linked to glucose intolerance.

The mechanisms behind all this aren't totally clear, but the authors suggest that inflammation may be the missing link. Altered populations of gut bacteria trigger an inflammatory response, which sets into motion changes in glucose metabolism. Artificial sweeteners aren't absorbed by the body so they pass through the intestines, and come into contact with the trillions of beneficial bacteria down there.

So is diet soda destroying your metabolism? Probably not – there are after all many factors that contribute to the metabolism. But if you’re one of the people who's susceptible to it, artificially sweetened products may play some role, along with the other factors. It’s worth reiterating that not all of the human subjects had the changes in their gut bacteria, only some did. It may be that certain people – or their gut microbes – are more susceptible to the effects of artificial sweeteners, while others are more resistant.

And again, this is not a direct connection. “This is an indirect effect,” says David L. Katz, Founding Director Yale University Prevention Research Center. “Artificial sweeteners are, obviously, not putting sugar directly into the bloodstream. Rather, they figure in the adulterations of diet that may alter the microbiome – and that, in turn, alters metabolic processing as described.” There are certainly ways to counteract the effect and push your gut microbes in a better direction – eating yogurt and other fermented products, and lots of fruits and vegetables are known to do this.

Artificial sweeteners may also have effects on other body parts besides the gut – like the brain. Katz points out that the new study “ignores another potential adversity of non-caloric artificial sweeteners: they are, in general, intensely sweet, and propagate a 'sweet tooth.' By doing that, they may cause people to favor added sugar in a wide variety of foods, and that increased glycemic load of diet may, in turn, contribute to glucose intolerance." In other words, your brain reacts to the extreme sweetness of the compounds as if they were sugar. It’s very possible that sugar substitutes might alter the complicated cascades behind how the brain perceives hunger and satiety, perhaps even altering the kinds of food we crave.

Still, the authors are confident that their studies provide strong evidence that gut bacteria are the connection between artificial sweeteners have their ironic effect on weight.

"Our relationship with our own individual mix of gut bacteria is a huge factor in determining how the food we eat affects us,” said study author Eran Elinav of the Weizmann Institute. Especially intriguing is the link between use of artificial sweeteners – through the bacteria in our guts – to a tendency to develop the very disorders they were designed to prevent; this calls for reassessment of today's massive, unsupervised consumption of these substances."

Whether or not the study will change regulations or recommendations on artificial sweeteners is unclear. Probably not until a lot more research is done. In the meantime, you may want to opt for tea or water instead of a diet soda. Your gut bacteria will thank you.

Also on Forbes:

Follow me on Twitter or LinkedInCheck out my website