Diet soda has been linked to a higher risk of developing type 2 diabetes than regular soda sweetened with an average of 8 teaspoons of sugar per can.
Whether the risk is related to the artificial sweetener aspartame or some other factor, has yet to be determined.
A study of French women, published in the current issue of the American Journal of Clinical Nutrition and an accompanying press release issued Feb. 7 by INSERM, the French National Institute for Health and Medical Research, explains the research.
Previous research has shown that one of the most common sweeteners, aspartame, has a similar effect on blood sugar and insulin levels as the sugar in regular sodas. “Contrary to conventional thinking, the risk of diabetes is higher with ‘light’ beverages compared with ‘regular’ sweetened drinks,”
the National Institute of Health and Medical Research (Inserm) said. Researchers led by Francoise Clavel-Chapelon and Guy Fagherazzi of INSERM evaluated information from over 66,000 middle-aged French women born between 1925 and 1950 over 14 years between 1993 and 2007 to investigate how the choices they made with regard to beverages affected their risk of diabetes. They divided the women into three groups; those who drank regular soda, those who drank artificially sweetened sodas and those who drank only unsweetened fruit juice.
Compared with the group of women who drank only juice women who drank either type of soda had a higher incidence of diabetes.
The increased risk was about a third for those who drank up to 359 millilitres (12 US ounces) of soda per week, and more than double among those who drank up to 603 ml (20 ounces) per week.
Those who drank diet sodas had an even greater risk of developing diabetes than their regular soda-drinking peers. The risk was 15 percent higher for consumption of 500 ml (16.9 ounces) per week, and 59 percent higher for consumption of 1.5 litres (50 ounces) per week.
The study found no increase in diabetes among women who drank only 100-percent fruit juice, compared with non-consumers of sweet beverages, i.e. those who drank only plain water and unsweetened tea and coffee.
The authors noted that women who chose the diet versions of soda tended to drink more of it, around 2.8 glasses a week on average compared to 1.6 glasses by women who drank the regular soda. When the researchers compared women who drank an equal amount of either soda, they found that the risk of developing diabetes was still greater for women who drank diet sodas.
The study authors admitted that the study was limited and urged that further research be conducted to ascertain whether there was a causal link between artificially sweetened beverages and increased risk of diabetes.
In the press release, the study authors explain some possible mechanisms for how these results might have occurred.
Several mechanisms can explain the increased risk of diabetes associated with high consumption of sweetened soft drinks:
“Firstly, in terms of calories, these drinks are no substitute for solid food because sweet soft drinks are not sufficiently satiating (so the calories in sweet soft drinks are added to the calories in solid food). Furthermore, the sugars contained in sweetened drinks produce an insulin peak reaction and repeated peaks of this kind can result in greater insulin resistance.
“With respect, in particular, to ‘light’ or ‘diet’ drinks, the relationship with diabetes can be explained partially by a greater craving for sugar in general by female consumers of this type of soft drink. Furthermore, aspartame, one of the main artificial sweeteners used today, causes an increase in glycæmia and consequently a rise in the insulin level in comparison to that produced by sucrose.”
“Information on beverage consumption was not updated during the follow-up, and dietary habits may have changed over time,” the paper said.
“We cannot rule out that factors other than ASB (artificially sweetened beverages)… are responsible for the association with diabetes.”
It is also possible that women who choose diet sodas are more likely to have pre-existing metabolic disorders, including obesity, insulin resistance and metabolic syndrome or that other dietary choices may play a role.
The study took into consideration the women’s age and body size, but did not keep close track of their eating habits during the study period and whether their dietary habits changed.
Diabetes is a burgeoning problem for both the developed and developing worlds with 347 million people worldwide having the condition according to the World Health Organisation.
Diabetes is a chronic disease which occurs when either the pancreas does not produce enough insulin to effectively control blood glucose levels or when the body does not respond adequately to the insulin produced.
Type 2 diabetes is associated with the former phenomenon and is frequently associated with excess body weight, overconsumption of calories, inadequate physical activity and stress. Type 1 diabetes is associated with the latter phenomenon and typically occurs during childhood, though rarely it can begin later in life. It requires pharmaceutically manufactured insulin to be injected into the body to replace the insulin that the body should be producing, but isn’t.
Over time, both forms of the disease if inadequately managed can cause damage to nearly every body system including the heart, blood vessels, eyes, kidneys, liver and nerves. The disease is known to increase the risk of heart disease, kidney failure, fatty liver disease, stroke and blindness.