The latest study published in the journal PLOS ONE examined the association between added sugar intake in tea and coffee and the risk of all-cause mortality in older Danes using a 32-year prospective cohort study.
The study also examined whether consumption of tea and coffee with added sugar was associated with mortality from cancer, cardiovascular disease and diabetes.
Background
Consumption of sugar-sweetened beverages, such as fruit juices and carbonated drinks, is associated with adverse outcomes in a dose-dependent manner, and increased consumption of sugar-sweetened beverages is associated with a higher risk of dyslipidemia, obesity, type 2 diabetes, all-cause mortality, and mortality due to cardiovascular disease and cancer.
Tea and coffee are two non-alcoholic beverages commonly consumed worldwide. Various studies have investigated the association between tea and coffee consumption and the incidence of all-cause mortality.
While coffee consumption shows a U-shaped association with all-cause mortality, tea consumption is thought to reduce the risk of all-cause mortality. However, although the amount of sugar added to tea and coffee is undoubtedly less than that present in sugar-sweetened beverages, the association between sugar consumption through tea and coffee and the risk of all-cause mortality has not been well studied.
About the study
In the current study, the researchers examined a cohort formed in 1970–1971, consisting of Danish men aged 40 to 59. Initial assessments of the cohort included a cardiorespiratory fitness test and physical examination, as well as a physician interview and a cardiovascular risk factor questionnaire.
Participants were also divided into three socio-economic classes based on occupation and education level.
People with higher education and academic degrees or who are self-employed and employ at least five workers were classified as having “high” education, people doing skilled white-collar or manual work were classified as having “medium” education, and manual workers doing unskilled work were in the “low” category.
The second follow-up visit took place in 1985-1986. At this visit, detailed clinical examinations were performed, including measurements of systolic and diastolic blood pressure and measurements of height and weight.
Participants also had to fill out a questionnaire about lifestyle factors such as alcohol consumption, smoking habits, and current and past medical conditions, including diabetes, cardiovascular disease, and cancer. The questionnaire also asked about their tea and coffee consumption and whether they drank these beverages with added sugar.
Subjects with diabetes, cancer, cardiovascular disease, or those who did not drink tea or coffee were excluded. The primary endpoint of the study was the incidence of all-cause mortality, while cardiovascular and cancer mortality and incident diabetes were secondary endpoints of the study.
Regression models were used to calculate Cox proportional hazard ratios to determine the association between sugar intake in tea and coffee and primary and secondary outcomes.
Results
The results indicated that in this population-based longitudinal cohort study of Danish men, sugar intake from tea and coffee was not significantly associated with all-cause mortality, diabetes, or death related to cardiovascular disease or cancer.
Of the 2,923 study participants, 1,007 reported consuming sugar with tea or coffee. Over 32 years of follow-up, the number of deaths in the no-sugar group and the sugar group was 1,677 and 904, respectively.
Scientists have discussed possible explanations for the lack of a significant association between the consumption of sugar-sweetened tea or coffee and the risk of death from any cause, cardiovascular disease or cancer.
Although previous studies have shown a mighty correlation between sugar-sweetened beverage consumption and an increased risk of adverse cardiovascular events and all-cause mortality, studies have shown that the amount of sugar added to an average cup of tea or coffee is about 5 grams, while sugar-sweetened beverages contain about 25 grams per can.
The results indicate a dose-response relationship between sugar consumption and the risk of all-cause mortality or diabetes.
The authors pointed out, however, that the study only looked at conventional coffee drinking methods, such as filtered black coffee, and did not include newer types of coffee, such as caramel Frappuccino, which may contain more added sugar.
Conclusions
Overall, the research evidence suggests that conventional methods of consuming tea or coffee with added sugar are not associated with a significant risk of death from any cause, cancer or cardiovascular disease, or diabetes.
