Methodology for the assessment of added/free sugar intake in epidemiological studies

Purpose of review High-sugar intake has been linked to increased risk of diseases but an accurate assessment of added/free sugar intake has always been a challenge in research. This review summarizes the methodologies for assessing added/free sugar intake reported in recent literature. Recent findings Four different methods for added/free sugar-intake assessment are discussed, including the carbon isotope ratio (delta C-13) method, Food Patterns Equivalent Database, disaggregation method and the 10-step systematic method. These methods have different strengths and limitations in terms of requirement for background knowledge, flexibility to sugar definition, level of subjectivity, accuracy and needs for recalculation/modification when used in different countries or food products. Summary Although advances have been made in the methodologies for assessing added/free sugar intake, accurate assessment continues to be difficult. Of the methods reviewed, the 10-step systematic method could be a simpler method to provide relatively accurate estimation of added/free sugar intake. Further improvements or combining with other methods may allow more accurate and flexible estimation. Development of a completely objective biomarker for added/free sugar intake is unlikely to be achievable, therefore future research may need to focus on developing correction equations for use with biomarkers such as delta C-13 to improve their specificity to added/free sugar intake.