Drinking more than two soft drinks per day – whether sugary or artificially sweetened – can double the risk of developing two types of diabetes, according to a new study published today in the European Journal of Endocrinology.
Type-2 diabetes is the most common form of diabetes, causing a person’s blood sugar levels to become too high because their cells are resistant to the hormone insulin. Type-1 diabetes is less common, where specialised beta cells in the pancreas cannot make enough insulin. A third type of diabetes, accounting for 9% of all cases and sometimes known as ‘type-1.5’ is Latent Autoimmune Diabetes in Adults (LADA), which develops in adulthood and shares characteristics of both type-1 and type-2. People with LADA typically have a normal BMI, and the progression of the disease means that the immune system mistakenly bombards insulin-producing beta cells, requiring patients to eventually need insulin injections, like people with type-1 diabetes.
In this study, researchers from the Karolinska Institute in Sweden investigated the impact of drinking sugary or artificially sweetened soft drinks on the risk of developing LADA or type-2 diabetes. They collected the self-reported eating and drinking habits of 2,874 Swedish adults (357 with LADA, 1136 with type-2 diabetes and 1371 healthy controls). The team evaluated the number of soft drinks each group consumed up to a year before their diagnosis, as well as measuring their levels of insulin resistance, beta cell function and autoimmune response.
The results showed that drinking more than two 200ml servings of soft drinks a day doubled the risk of LADA and increased the risk of developing type-2 diabetes 2.4-fold. Consuming five daily servings increased the risk of developing LADA 3.5-fold and type-2 diabetes 10.5-fold. The increased risk of developing either type of diabetes was the same for either sugary or artificially sweetened soft drinks. There was no measurable link between soft drink consumption and autoimmune response in LADA patients.
“It was interesting to find that the autoimmune response to the number of soft drinks consumed stayed the same,” said Josefin Edwall Löfvenborg, lead author of the study. “This could mean that the increased risk of developing LADA in relation to soft drink consumption isn’t directly caused by the immune response killing beta cells – which is what we see in type-1 diabetes.”
People with LADA have a degree of insulin resistance like type-2 diabetes patients, explains Josefin, so it could be that soft drinks increase the risk of both LADA and type-2 diabetes by influencing glucose metabolism and insulin sensitivity.
“In this study we were surprised by the increased risk in developing autoimmune diabetes by drinking soft drinks,” said Josefin. “We next plan on investigating what could counter this risk, such as eating fatty fish. We are looking into this now using data from eight different countries across Europe.”
Whilst this study discusses the relative risk of developing LADA and type-2 diabetes, it does not discuss the absolute risk of developing either of these conditions, though it is estimated 1 in 11 people worldwide have diabetes. The study also had a retrospective design, and patients were asked to recall their eating habits in the preceding year, potentially leading to bias.