Sweetener or sugar

A series of tests on mice and humans indicates that artificial sweeteners may have a negative effect on gut bacteria, leading to negative changes in how the body responds to carbohydrate.

The study was carried out by researchers from the Weizmann Institute of Science in Israel and the results published in the journal Nature.

The mouse studies involved feeding the mice with either a sweetener, water or sugar in water. The following three sweeteners were tested:

  • Saccharin which is used in Sweet ‘N Low
  • Sucralose used within Splenda
  • Aspartame used within NutraSweet

20 mice were used in the testing which lasted 11 weeks. After the 11th week, the mice were given sugar and the researchers tested the blood glucose response of the mice. The results showed that the mice that had been given sweeteners over the 11 weeks responded to having sugar with significantly higher blood glucose results than the mice that had sugar or water. Further tests were then run which demonstrated that effects on gut bacteria linked feeding of the artificial sweeteners with high blood sugars.

The next part of the study involved research on humans. 381 people without diabetes were recruited to take part in a survey to assess the amount of artificial sweeteners in their diet. Levels of glucose tolerance were also measured and the results showed that the participants with the highest intakes of artificial sweetener displayed greater levels of glucose intolerance.

To explore the effects in more detail, the researchers carried out a test on seven healthy human participants that were required to take the maximum allowable dose of saccharin per day for a week. None of these participants were regular users of artificial sweeteners before the study. After a week, glucose tolerance tests showed that four of the seven participants had experienced a worsening of blood glucose response. These four participants also displayed significant changes in their gut bacteria.

The study suggests that further research is required to investigate the effects that artificial sweeteners have on the body. The study was a small study and therefore can only suggest rather than conclusively prove that sweeteners have negative effects on gut bacteria and blood glucose response.

The study raises some specific concerns over saccharin and more research could establish whether there are significant health risks with taking this particular sweetener. Detailed research will also be needed to analyse whether there are health risks, such as altered gut bacteria and high blood glucose levels, associated with the sweeteners aspartame and sucralose. The findings are not currently conclusive or serious enough to warrant a change in diet for people who use sweeteners.