Not so sweet: artificial sweeteners might mess with your microbiome

Artificial sweeteners are often regarded as one of the many weapons in the battle against a widening waistline, but now there’s a suggestion they could have a less-than-positive effect on the human microbiome.

Research from Israel’s Weizmann Institute of Science, has found non-nutritive sweeteners – chemicals that provide no energy or nutritional benefit – can influence the functioning of people’s microbiome and glycaemic responses.

These products include saccharin, sucralose, aspartame and stevia.

A two-week trial saw a group of 120 healthy adults administered below-recommended doses of these sweeteners, with researchers monitoring their physiological responses, while control groups were given glucose or no supplement.

They found these sweeteners altered the microbiomes in stool and the mouth as well as the metabolome (the composition of small molecules) of blood plasma.

Saccharin and sucralose were also found to impair glycaemic responses – meaning the may reduce tolerance to glucose, which is the most common dietary sugar.

The research, published in Cell, is a follow up to a previous study conducted by senior author Professor Eran Elinav, which found similar glycaemic changes in mice.

He wanted to see whether artificial sweeteners triggered similar results in people.

“We could identify very distinct changes in the composition and function of gut microbes, and the molecules they secret into peripheral blood,” he says.

“This seemed to suggest that gut microbes in the human body are rather responsive to each of these sweeteners.

“Two of the non-nutritive sweeteners, saccharin and sucralose, significantly impacted glucose tolerance in healthy adults.

“Interestingly, changes in the microbes were highly correlated with the alterations noted in people’s glycemic responses.”

Artificial sweeteners are widely used in a range of products

Now ubiquitous alongside sugar sachets in cafes and coffee shops, you probably know artificial sweeteners by brand names like Sweet ‘N Low (saccharin), Splenda (sucralose) and Equal (aspartame).

Packets of splenda and equal artificial sweeteners

Credit: Bukowsky18 (CC BY-NC-SA 2.0

But these chemical are also used in other products.

Saccharin can be found in some toothpastes and mouthwashes, while you might spot sucralose on the label of low-fat ice cream, vitamins or protein powders.

Aspartame is used in soft drinks like Diet Coke, Coke No Sugar and Pepsi Max.

Although Elinav expects responses to artificial sweeteners to vary from person to person thanks to the highly personalised characteristics of the human microbiome, he says the findings show they are not as passive as previously thought.

Previous studies have suggested while artificial sweeteners are largely considered safe for human consumption, their use could lead to other complications like Type 2 diabetes.

“The clinical health implications of the changes they may elicit in humans remain unknown and merit future long-term studies,” he says.

“In the meantime, we need to continue searching for solutions to our sweet tooth craving, while avoiding sugar, which is clearly most harmful to our metabolic health.”

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