Supplements are routinely consumed by many in the US, and they contribute towards the intake of nutrients and nonnutritive dietary ingredients. Estimating nutrient intake from foods and beverages is routinely done using questionnaires to determine intakes for populations or groups of people. Some studies have included supplement questionnaires as part of a diet survey, but their accuracy has not been the subject of many studies. By not determining nutrient intakes from supplements or doing so with an inaccurate assessment tool, nutrient and disease associations found may be misleading. Steffen and colleagues conducted a study to evaluate the accuracy of a supplement intake frequency questionnaire and report their results in the August 2021 issue of The Journal of Nutrition.
Subjects for this work were part of the Multiethnic Cohort who reported regular use of dietary supplements (n=1029). Two short, self-administered supplement frequency questionnaires were completed by all participants (1 year apart). Quarterly in home interviews were performed with 375 participants to collect detailed information on the types and amounts of supplements used, whereas the remaining 654 served as a control group and only completed the questionnaires.
Agreement on the prevalence of intake between the questionnaire and in person interviews was quite high for all supplements measured, except for vitamin D. Reported mean intakes for most nutrients were higher on the questionnaire, compared to those from the interview. Intakes documented on the questionnaire were similar between the control and interview groups. The authors concluded that a short supplement survey could be used to rank intake of nutrients among study participants, but that it did not accurately estimate absolute intake levels acquired from supplements.
In a commentary, Gahche and Bailey noted that this study is one of the few that have attempted to validate questionnaires designed to collect data on supplement use and nutrient intake. They state the lack of specific details on supplements (brand, formulation, and doses) in most studies limit the rigor of the data obtained. They suggest further work is needed to make methodological advances that increase accuracy of the data collected.
Alana D Steffen, Lynne R Wilkens, Kim M Yonemori, Cheryl L Albright, Suzanne P Murphy, A Dietary Supplement Frequency Questionnaire Correctly Ranks Nutrient Intakes in US Older Adults When Compared to a Comprehensive Dietary Supplement Inventory, The Journal of Nutrition, Volume 151, Issue 8, August 2021, Pages 2486–2495, https://doi.org/10.1093/jn/nxab140.
Jaime J Gahche, Regan L Bailey, Accurate Measurement of Nutrients and Nonnutritive Dietary Ingredients from Dietary Supplements Is Critical in the Precision Nutrition Era, The Journal of Nutrition, Volume 151, Issue 8, August 2021, Pages 2094–2095, https://doi.org/10.1093/jn/nxab237.
Images via canva.com.