Lab Mouse

Don’t Feed High-Dose Saccharin to Your Mice

We’re getting a series of headlines this week about  saccharin and other low-calorie sweeteners, declaring:

“Zero-Calorie Sweeteners Can Raise Blood Sugar”
“Artificial Sweeteners May Lead to Diabetes”
“Artificial Sweeteners Could Cause Spikes in Blood Sugar”
“Low-calorie Sweeteners Found in Diet Drinks RAISE the Risk of Obesity and Diabetes”

 What is this ground-breaking research that has generated literally hundreds of headlines in just a few days? It’s a paper in Nature that summarizes research on the effects of high-dose saccharin in mice on their gut microbes and a study of the gut microbes in just seven humans. They’ve generated some interesting theories and targets for future research, but conclusive evidence about nothing in humans.

Undeterred by the limitations of their research, the authors are sweeping in their conclusions, “calling for a reassessment of massive NAS [non-caloric artificial sweetener] usage.”

More careful scientists are suggesting more careful interpretations. Peter Turnbaugh, a microbiologist at Harvard University, said:

This is really fascinating work. But there’s a lot more basic biology that will need to be worked out to fully appreciate the mechanisms that cause sweeteners to alter gut microbial community composition and function, and how in turn this shapes host metabolism.

Catherine Collins, principal dietitian at St George’s Hospital in London, was more blunt:

If you’re a human trying to lose weight, you need to lose calories from your diet. Low calorie sweeteners help reduce your calorie intake from previous sugar or sugary drink use, and it’s a good lifestyle move for those wanting to lose weight and control blood sugar levels.

However, if you’re a lab mouse, with your regular mouse chow providing a typical 60% of calories from fat, it seems that high dose sweeteners added to your drinking water alters blood glucose metabolism – and not in a good way. On this evidence, I’d agree that lab mice shouldn’t have lots of sweeteners in their drinking water.

We’ve been down this path before with irrelevant warnings about saccharin. Starting in the 1970s, saccharin carried a warning about causing cancer in lab animals. By 2000, those warnings were removed when FDA accepted the well-established understanding that this concern was limited to rodents.

These guys can fight all they want about sweeteners. They won’t listen to reason anyway. But they better not touch our chocolate — even if it is toxic to dogs.

Click here to read the study and here to read a commentary printed along with it. Click here to read more from Science magazine.

Lab Mouse, photograph © Novartis AG / flickr

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