MedicalResearch.com Interview with:
Dr Nita Forouhi, MRCP, PhD, FFPHM
MRC Programme Leader and Consultant Public Health Physician
MRC Epidemiology Unit
University of Cambridge School of Clinical Medicine
Cambridge Biomedical Campus
Medical Research: What is the background for this study? What are the main findings?
Dr. Forouhi: Consumption of soft drinks is known to cause obesity and may contribute to the development of type 2 diabetes. We had previously published findings from the EPIC-InterAct study in 8 European countries that habitual consumption of sugar sweetened beverages increases the risk of developing type 2 diabetes, and we now wanted to probe deeper to understand more about this relationship between sweet beverages and diabetes.
We conducted research in the large EPIC-Norfolk study which included more than 25,000 men and women aged 40–79 years living in Norfolk, UK. Study participants recorded everything that they ate and drank for 7 consecutive days covering weekdays and weekend days, with particular attention to type, amount and frequency of consumption, and whether sugar was added by the participants. During approximately 11 years of follow-up, 847 study participants were diagnosed with new-onset type 2 diabetes.
By using this detailed information on diet, we were able to study several different types of sugary beverages, including sugar-sweetened soft drinks, sweetened tea or coffee and sweetened milk drinks as well as artificially sweetened beverages (ASB) – such as diet soft drinks – and fruit juice, and to examine what would happen if plain water, unsweetened tea or coffee or artificially sweetened beverages were substituted for sugary drinks.
Our study provided three main findings:
First, there was an approximately 22% increased relative risk of developing type 2 diabetes per extra serving per day habitually of each of soft drinks, sweetened milk beverages and ASB consumed, even after accounting for a range of important factors including other lifestyle and social factors and for total energy intake. However, after further accounting for body mass index and waist girth as markers of obesity, there remained a higher risk of diabetes associated with consumption of both soft drinks and sweetened milk drinks, but the link with ASB consumption no longer remained, possibly because artificially sweetened beverages was likely to be consumed by those who were already overweight or obese.
Second, when we estimated the likely effects of replacing a habitual serving of soft drinks with a serving of water or unsweetened tea or coffee, we found that the risk of diabetes could have been cut by 14%; and by replacing a habitual serving of sweetened milk beverage with water or unsweetened tea or coffee, that reduction could have been 20%–25%. However, consuming ASB instead of any sugar-sweetened drink was not likely to reduce the risk of diabetes, when accounting for baseline obesity and total energy intake.
Third, we found that each 5% of higher intake of energy (as a proportion of total daily energy intake) from total sweet beverages (soft drinks, sweetened tea or coffee, sweetened milk beverages, fruit juice) was associated with a 18% higher risk of diabetes. We estimated that if study participants had reduced the energy they obtained from sweet beverages to below 10%, 5% or 2% of total daily energy, 3%, 7% or 15% respectively of new-onset type 2 diabetes cases could have been potentially avoided.