A new study reported in the journal Nature suggests that artificial sweeteners may increase glucose intolerance and thus the risk of developing diabetes because they affect gut bacteria.

In laboratory trials scientists gave mice water to which 3 commonly used sweeteners had been added.   The mice developed glucose intolerance – a condition where blood sugar levels rise – which is a risk factor for type ll diabetes that currently affects almost 3 million people in the UK.

The sweeteners affected the balance of gut bacteria that are linked to the development of metabolic diseases such as obesity, high blood pressure, diabetes and heart disease.  In addition, a small group of human volunteers developed glucose intolerance after only one week of taking artificial sweeteners.

Dr Eran Elinav, from the Weizmann Institute in Rehovot, Israel, said: “This calls for reassessment of today’s massive, unsupervised consumption of these substances.”

In the study 2 different populations of human gut microbes were identified, one that induced glucose intolerance when exposed to the sweeteners and another that did not, and this was dependent on the kind of bacteria found in the gut.

The researchers believe that some bacteria provoked an inflammatory response, similar to an overdose of sugar, when exposed to the sweeteners.

Ironically, artificial sweeteners are marketed as a substance that helps people slim and maintain weight management although it seems the reverse may be true and they are in fact contributing to the obesity and diabetes epidemic.

There have been numerous studies that have shown that the gut microflora of obese people and lean people are different and that manipulation of gut bacteria can help suppress appetite and control glucose intolerance.

Back in 2004 reserachers from Purdue University, Indiana proposed that diet drinks may make slimmers fatter.

They said the taste of artificial sweeteners found in low-calorie drinks damage the body’s ability to link sweetness with high calorie content in other items.

Professor Terry Davidson said: ‘The body’s natural ability to regulate food intake and body weight may be weakened when this natural relationship is impaired by artificial sweeteners.

Without thinking about it, the body learns that it can use food characteristics such as sweetness and viscosity to gauge its caloric intake. The body may use this information to determine how much food is required to meet its calorific needs.

When you substitute artificial sweetener for real sugar, however, the body learns it can no longer use its sense of taste to ‘count’ calories.

This finding may explain why increasing numbers of people lack the natural ability to regulate food intake and body weight.’

Artificial sweeteners are not just found in ‘zero calorie’ drinks.  They are added to numerous convenience and processed foods so you should be looking out for labels that claim ‘low calorie’; ‘sugar free’; ‘diet’ amongst others.

Ideally, we should be trying wean ourselves off the constant need to consume sweet foods and drinks – the best drinks for those wanting to control their weight is good old plain water!