Sugar in tea or coffee did not increase the risk of death and diabetes
Researchers from three countries studied data on nearly three thousand Danes and found that adding sugar to tea or coffee did not increase the risk of diabetes or death. The cohort was followed for 32 years. The study is published in the journal PLoS ONE.
People around the world drink tea and coffee, often adding sugar to them. Scientists have often studied the effects of these drinks on human health: for example, some large observational studies have found a U-shaped association between the amount of coffee consumed per day and all-cause mortality; tea consumption has also been associated with a reduced risk of all-cause mortality. However, there has been little study of the effects of the extra sugar added to these drinks.
It is known, however, that sweetened beverages such as sodas and fruit juices, for example, have a dose-response relationship with adverse health effects. Specifically, there is an increased risk of obesity, dyslipidaemia and type 2 diabetes. Every 350 millilitres of sugary drinks is thought to increase the risk of all-cause mortality.
Magnus Jensen from Queen Mary University of London and colleagues from Denmark and the Netherlands studied the association between added sugar in coffee or tea and all-cause mortality over 32 years of follow-up in a prospective cohort of elderly Danish men. In addition, the researchers investigated the association between added sugar and mortality from cardiovascular disease, cancer and diabetes mellitus. The study cohort included 2,923 healthy Danes who reported in a questionnaire the amount of tea or coffee consumed and added sugar (2,790 volunteers were included in the multivariate analysis).
The mean age of the participants was 62.7 years. They had statistically significant differences in age, body mass index, systolic blood pressure and smoking status between the group taking sugar and the group not taking sugar. During 32 years of follow-up, 2,581 participants (88.3 per cent) died. In the group not taking sugar, 1677 participants died, and in the group taking sugar, 904 participants died. The risk ratio in the sugar group compared with the no-sugar group was 1.06, and the correlation coefficient between the number of cups of coffee or tea per day and added sugar was 0.99. Cox regression analysis additionally showed that there was no relationship between added sugar and number of cups of coffee and all-cause mortality. There was no increased risk of death from cardiovascular disease, cancer, or diabetes.
Scientists explain the found patterns (or rather their absence) by the fact that on average people add five grams of sugar to tea or coffee, while the average can of sweetened beverage contains 25 grams of sugar. Since there is a dose-effect relationship between sugar intake and mortality, the amount of sugar consumed with coffee or tea may simply be too low to significantly affect life expectancy and the risk of developing diabetes.