The new small scale study, published in Diabetes Care , analysed how intake of the sweetener sucralose (in this case Splenda)affected the metabolic responses of 17 severely obese yet otherwise healthy people - finding that sucralose intake was responsible for up to a 20% spike in blood sugar and insulin levels when the participants were given a later 'dose' of glucose.
"Our results indicate that this artificial sweetener is not inert — it does have an effect," said Dr Yanina Pepino from the Washington University School of Medicine - first author of the study.
However, Matthew Wootton, group VP, investor and media relations for Tate & Lyle said there have been 'numerous' clinical studies in both diabetic and non-diabetic people over the years - and all have shown that sucralose is safe for consumption.
"EFSA, FDA and many other regulators have concluded that sucralose does not adversely affect glucose control," he told FoodNavigator.
"You have to look at the extensive tests that have been carried out over the years - they have shown sucralose to be safe for the whole population."
Pepino and her team studied people with an average body mass index (BMI) of just over 42 - giving them either water or sucralose to drink before they consumed a glucose challenge test.
"When study participants drank sucralose, their blood sugar peaked at a higher level than when they drank only water before consuming glucose," she explained. "Insulin levels also rose about 20% higher. So the artificial sweetener was related to an enhanced blood insulin and glucose response."
"Whether these acute effects of sucralose will influence how our bodies handle sugar in the long term is something we need to know," she added - noting that such changes to metabolism may not have harmful effects.
"What these all mean for daily life scenarios is still unknown, but our findings are stressing the need for more studies."
Wootton commented that the study did not involve people with diabetes and only used a small number of subjects:
"Importantly, the study is not backed by the extensive scientific data available," said the Tate & Lyle VP.
" The study included no control or review of the diet or lifestyle of participants in days building up to the tests and used subjects who were excessively overweight.'
The team tested each of the 17 participants twice in a crossover study that meant each participant acted as their own control.
Analysis of this data revealed that compared to drinking water sucralose ingestion led to a greater incremental increase in peak plasma glucose concentrations, an average of a 20% increase in insulin levels, a 22% jump in peak insulin secretion rate, a 7% decrease in insulin clearance , and a 23% decrease in insulin sensitivity.
"The artificial sweetener was related to an enhanced blood insulin and glucose response," said Pepino.
"Although we found that sucralose affects the glucose and insulin response to glucose ingestion, we don't know the mechanism responsible," she added. "We have shown that sucralose is having an effect. In obese people without diabetes."
"We have shown sucralose is more than just something sweet that you put into your mouth with no other consequences."
However Pepino added that such elevations in responses 'could be a good thing' because it shows that person is able to make enough insulin to deal with spiking glucose levels.
On the other hand, she said, that the findings may have negative implications because "when people routinely secrete more insulin, they can become resistant to its effects, a path that leads to type 2 diabetes."