The Reproducibility and Comparative Validity of a Non-Nutritive Sweetener Food Frequency Questionnaire

In order to better assess non-nutritive sweetener (NNS) consumption, measurement tools with greater utility are needed. The objective of this investigation is to determine the reproducibility and validity of a newly developed NNS food frequency questionnaire (NNS-FFQ) that measures five types of NNS (saccharin, aspartame, acesulfame potassium, sucralose and erythritol). Adult participants (n = 123, 56% female, 75% Caucasian, mean age = 36.8 ± 16.6) completed the NNS-FFQ twice and had 24-h dietary recalls three times over a two-week study period. Reproducibility between two administrations of the NNS-FFQ was assessed via Bland–Altman plots, Spearman’s correlations (r(s)) and paired samples t-tests. Bland–Altman plots, Cohen’s κ, Spearman’s correlations (r(s)), and paired samples t-tests compared NNS intake between the two methods for validity. For reproducibility analyses, Bland–Altman analyses revealed agreement levels above the 95% acceptance level for total NNS (99.2%), erythritol (99.2%), and aspartame (96.7%). Agreement levels for acesulfame potassium (94.3%), saccharin (94.3%), and sucralose (94.3%) were slightly below the acceptable level. For validity analyses, Bland–Altman analyses revealed agreement levels above the 95% acceptance level for total NNS (95.1%), sucralose (95.9%), saccharin (95.9%), and erythritol (95.1%). Agreement levels for aspartame (94.3%) and acesulfame potassium (92.7%) were slightly below the acceptable level. Although less than desirable agreement was found between the methods for aspartame and acesulfame potassium, some variance was expected due to the habitual nature of the NNS-FFQ as compared to the recent intake reported by recalls. Within the context of this constraint, the NNS-FFQ demonstrates acceptable reproducibility and validity. The NNS-FFQ is a brief questionnaire that could be administered among diverse participants at the individual and population levels to measure habitual NNS intake.