Aspartame could prevent weight loss, US researchers report

A sugar substitute commonly found in diet products could have the opposite effect to weight loss, according to a new study.
Aspartame is used in a variety of diet drinks, yoghurts and chewing gum and it is roughly 200 times sweeter than sugar.
A team of US researchers looked at the artificial sweetener and found a link between increased hunger and calorie consumption.
Lead author Dr Richard Hodi, from the Massachusetts General Hospital’s (MGH) Department of Surgery, said: “Sugar substitutes like aspartame are designed to promote weight loss and decrease the incidence of metabolic syndromen, but a number of clinical and epidemiologic studies have suggested that these products don’t work very well and may actually make things worse.
“We found that aspartame blocks a gut enzyme called intestinal alkaline phosphatase (IAP) that we previously showed can prevent obesity, type 2 diabetes and metabolic syndrome; so we think that aspartame might not work because, even as it is substituting for sugar, it blocks the beneficial aspects of IAP.”
The team compared four groups of mice on different diets as part of the study: two groups were fed a normal diet, one of which was given water mixed with aspartame and the other received water without the sweetener; and the other two groups were given a high-calorie diet, which again were split between sweetened water and without.
The findings showed the group which received a high-calorie diet with the aspartame water put on more weight when compared to the mice on the same diet that drank plain water.
The mice in both diet groups, which were given aspartamen, had higher blood sugar levels and blood pressure than the animals who did not receive the sugar substitute, which could suggest glucose intolerance.
Dr Hodi, who is also a professor of Surgery at Harvard Medical School, said: “People do not really understand why these artificial sweeteners don’t work. There has been some evidence that they actually can make you hungrier and may be associated with increased calorie consumption.
“Our findings regarding aspartame’s inhibition of IAP may help explain why the use of aspartame is counterproductive. While we can’t rule out other contributing mechanisms, our experiments clearly show that aspartame blocks IAP activity, independent of other effects.”
The study appears online in the journal Applied Physiology, Nutrition, and Metabolism.