The Not So Sweet Side of Artificial Sweeteners

Health, Science 2014-11-10

Artificial sweeteners are sugar substitutes commonly used in fizzy drinks, cereals and desserts to provide the sweetness of sugar at a lesser calorific expense. Many of these sweeteners have zero calories per gram yet are anywhere from 30 to 8,000 times sweeter than sugar, so they are marketed as guilt-free way of satisfying your sweet tooth.


Sugar substitutes were developed to aid in weight loss and the control of diabetes as they allow dieters to enjoy a wider range of foods without putting them in any calorie, fat or carbohydrate debt. This is especially useful to control the sugar intake of overweight people and diabetics.


artificial sweeteners


However, a recent study suggests that these sweeteners could actually speed up the development of glucose intolerance, which is characterised by the body’s inability to deal with large amounts of sugar and often leads to metabolic diseases such as diabetes and obesity. The theory behind this research was that these sweeteners could interfere with the composition and function of bacteria found in the gut, thereby changing the metabolism of glucose and increasing blood sugar levels in the body.


The study, carried out at the Weizmann institute of Science in Israel, was conducted on 10-week old mice. The experimental group were given water laced with saccharinsucralose or aspartame, while the controls drank either plain water or water mixed with glucose or sugar. After one week the group with the artificial sweeteners had developed distinct glucose intolerance, whereas the plain/sugar laced groups showed minimal changes. When the mice were treated with antibiotics to destroy the gut bacteria, the tolerance to glucose was restored, which suggested that a reaction to the sweeteners by the microbes could be contributing to the development of glucose intolerance. This hypothesis was supported when the team sequenced the DNA and found that saccharin modified the diversity of the gut bacteria in the mice.


Following these promising results in mice, a study was conducted on 381 non-diabetic human participants. The findings not only demonstrated a link between the artificial sweeteners and glucose intolerance, but also that it only took 4 days for 7 volunteers who hadn’t consumed sweeteners previously to become intolerant. Their gut bacteria became altered in a similar way to the mice in the earlier study.


Despite finding a link between gut bacteria and the development of glucose intolerance, researchers were unable to find the exact interaction between the sweeteners and the intestinal microbes. It was also unclear why the three different molecules that were tested triggered similar changes in the metabolism of glucose. It is possible that the microbes may thrive off the sugar substitutes, therefore energy can be extracted from the food and more fat stored, or sweeteners could be causing an expansion of the bacteria that extract energy from food. Alternatively artificial sweeteners could be suppressing the growth of other bacteria, which are needed to stave off insulin resistance.


The British Soft Drinks Association and the International Sweeteners Associationhave rejected this research. It has also received criticism from dieticians and nutritionists, claiming it appears to contradict an overwhelming body of scientific evidence, which shows no link between use of sweeteners and the development of metabolic disease.


These results suggest that there is a need to reassess the current massive, unsupervised consumption of these substances, as there is a chance that rather than improving metabolism and fighting obesity these sugar substitutes could be contributing to the colossal rise in obesity and diabetes.


It is hard to say how much of an impact supportive findings could have on current diet trends. It could be a similar story to that of energy drinks, which, despite repeatedly being linked to heart rhythm problems, have seen sales in Great Britain alone soar to £1.5bn this year. This research raises questions about whether artificial sweeteners can really be portrayed as a guilt-free sugary fix, however it doesn’t provide sufficient evidence to alter public health and clinical practice.


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