In an attempt to establish the safety of zero-calorie sweeteners, researchers from the US National Institutes of Health fed them to pregnant and lactating mice. They were given sucralose and acesulfame-K, a common formulation in sugar-free fizzy drinks.
Dr. John Hanover, the study’s senior author, said: “Non-nutritive sweeteners are generally believed to be safe when used in moderation. However, sweetness itself seems to some extent mimic the effects of sugar – triggering insulin secretion, inflammation and changes to the gut microbiome – which promote fat storage and type 2 diabetes.”
Because sweeteners are known to be passed on in small amounts via the placenta and breast milk, the researchers wanted to establish whether similar metabolic and microbiome changes occur in offspring following maternal sweetener intake.
They fed mouse mothers one of three sweetener solutions throughout pregnancy and lactation, and analysed the effects on their pre-weaned pups.
Dr. Kristina Rother, who also worked on the study, said: “Sweeteners are often used in combination, partly because a blend can reduce the unpleasant bitter taste that some consumers experience. Combining sweeteners might also amplify the metabolic and microbiome effects – so we used the typical pairing of sucralose and ace-K to maximize the applicability of our results.”
Analysis of blood, faeces and urine from a total of 226 pups confirmed that both sweeteners are transmitted prenatally – and as predicted, affect the metabolism and microbiome of the offspring.
While the pups’ exposure was low, the researchers found significant metabolic changes. Specifically, these changes indicated impaired liver functioning in clearing toxins from the blood, and a dramatic shift in bacterial metabolites in the gut. In both sweetener groups the researchers observed the loss of a major beneficial species of gut bacteria, Akkermansia muciniphila. Similar microbiome alterations in humans have been linked to type 2 diabetes and obesity.