Recent studies on artificial sweeteners change the discussion

Previously, the focus on artificial sweeteners was on safety.
Now the discussion has broadened to include effects on gut bacteria.

You may be aware that there has been a flurry of media articles about a new study on the safety of artificial sweeteners recently — and may be wondering whether you should be changing what you eat. Here is my take on the issue after reading both the original research and previous studies on the topic.

Some evidence of glucose tolerance

On one level, the results of the new study(1) are fairly clear: mice fed saccharin at a level equivalent to the maximum daily recommended amount for humans (9 packages per day) developed a modest impairment in glucose tolerance. The study authors implied that they saw a smaller version of same effects when using other sweeteners, but did not say whether those effects were statistically significant, and chose to focus most of the experiments on saccharin. The mechanism identified in the study was that saccharin (which is indigestible) caused a change in the types of bacteria living in the large intestine, which in turn caused some degree of inflammation and metabolic effects. I realize that this all sounds rather unlikely, but in fact intestinal bacteria are increasingly recognized to have effects throughout the body, so from the scientific perspective this is not implausible. Overall I judged the study results to be real, for saccharin at least, but of quite small magnitude.

Are humans like mice? Are all non-caloric sweeteners the same?

The harder question is what this all means for us. It is certainly true that impaired glucose tolerance is a risk factor for diabetes, which is something none of take lightly. On the other hand, the effects were pretty small and mostly from experiments in mice — with unknown relevance to humans. The researchers did give saccharin to 7 humans a well, and showed that 4 had perhaps comparable responses in a short-term study, whereas the other 3 apparently did not and were considered to be ‘non-responders’. Clearly, not all artificial sweeteners will have the same effects, since the effect of one chemical in the intestine will not be the same as the effect of a different chemical — and for the most part artificial sweeteners all have really different chemical compositions. However, the specter has been raised that artificial sweeteners need more scrutiny, and clearly more research is needed.

Further studies needed

iDiet believes that the best use of artificial sweeteners is as a bridge in the transition to a low-sugar diet. Based on this new research, I now suggest that it makes sense to avoid saccharin while we wait for additional research to confirm or reject the results. However I don’t see that the evidence against other artificial sweeteners is credible at this time, especially since other studies have found the opposite result — no promotion of glucose intolerance. And it is important to remember that, for those of us who miss a sweet taste, they do seem to help weight control — which of course remains the crucial priority for maintaining health. Nutrition research is plagued with isolated studies that are not confirmed in subsequent research so, as we wait for more research, I will personally be avoiding saccharin (the pink packets) and other saccharin-containing products, but will continue to have moderate amounts of other artificial sweeteners with an easy mind.

Susan B Roberts, PhD
iDiet Founder

(1) http://www.nature.com/nature/journal/vaop/ncurrent/full/nature13793.html