Artificial sweeteners could increase the risk of developing type two diabetes, research suggests.
Scientists found consuming high quantities of the sweeteners - which are used in diet drinks, breakfast cereals and other foods - changes the way the body responds to sugar.
Having high spikes and low troughs in blood glucose levels - the main feature of diabetes - can be extremely dangerous.
In a healthy person the human body naturally slows down the rate at which sugar is absorbed into the blood after a meal.
But experts found that people who consumed lots of artificial sweeteners for two weeks - the equivalent to drinking five cans of diet drink a day - showed a significantly reduced ability to control glucose absorption.
Over time, this could lead to the development of type two diabetes, they warned.
The Australian research team, led by Professor Richard Young of the University of Adelaide, tracked 27 healthy volunteers who were given one of two different sweeteners - sucralose or acesulfame-K - or a dummy 'placebo'.
Experts found that people who consumed lots of artificial sweeteners (file picture) for two weeks showed a significantly reduced ability to control glucose absorption
These were consumed in the form of capsules taken three times a day before meals over the two-week study period, in the same daily levels as would be found in 1.5 litres of diet drink.
At the end of the two weeks, subjects underwent tests of their glucose response, blood sugar levels, and levels of insulin and gut peptides.
Women with diabetes who drink a cup of tea or coffee a day can expect to live a longer life, research suggests.
Experts found that regular caffeine consumption was linked to women living longer compared to those who drank no caffeine at all.
The research, presented at the European Association for the Study of Diabetes annual meeting in Lisbon, found no such association between caffeine and men with diabetes.
Experts from the University of Porto looked at caffeine and death rates in more than 3,000 men and women with diabetes.
The people in the study reported their caffeine intake from coffee, tea, and soft drinks over 24 hours at the point they enrolled in the research.
They were the tracked for the following 11 years.
The researchers found that women who consumed the equivalent of one cup coffee a day were 51 per cent less likely to die during the 11 years, increasing to 57 per cent for those two cups, and 66 per cent for more.
Analysis showed that coffee-drinking was linked to a lower risk of death from any cause, particularly cardiovascular disease, while women who consumed more caffeine from tea appeared to be less likely to die from cancer.
The authors said: 'Our study showed a dose-dependent protective effect of caffeine consumption on all-cause mortality among women.
'The effect on mortality appears to depend on the source of caffeine, with a protective effect of coffee consumption on all-cause mortality and cardiovascular mortality, and a protective effect of caffeine from tea on cancer mortality among women with diabetes.
'However, our observational study cannot prove that caffeine reduces the risk of death but only suggests the possibility of such a protective effect.'
The researchers did not look at exactly why caffeine had such an impact, but previous studies have suggested the the other antioxidant plant compounds in tea and coffee - rather than the caffeine itself- is probably responsible for the benefits.
Coffee contains a number