Use of duplicate plate method to evaluate dietary assessment methods
Abstract
The increased awareness of calcium and health outcomes, along with the acknowledgement of nationwide inadequate calcium intake, has led to a growing market of calcium-fortified foods in the US. Interviews done in 12 states with 203 primary food providers for early adolescents (10-13 year old) suggested that a noticeable proportion of the intentional purchasers of fortified foods failed to correctly identify such products while some individuals purchased fortified foods without awareness. This brings the challenge in assessing dietary calcium intake from all food sources. The primary objective of this study was to compare self-reported and objective measure of calcium intakes in order to identify specific dietary assessment tool(s) that could comprehensively capture all dietary calcium sources among Asian, Hispanic, and non-Hispanic White women. Self-reported dietary intake was assessed with food records, a calcium-specific food frequency questionnaire, and the Block food frequency questionnaire. With the duplicate plate collection being the direct reflection of actual food consumption, data suggested food records were able to capture dietary calcium sources more thoroughly and accurately than food frequency questionnaires among 50 women from the targeted race/ethnic groups. Food records estimated calcium intake almost identical as the duplicate plate collection. As a sub-study of the project, comparison of self-reported energy intake with objective measure of energy intake further showed the subjects reported statistically equivalent or higher energy intake in the FR than in the DPC. Calcium and energy data jointly suggested that this group of highly-educated subjects were able to record all duplicated foods with adequate details and/or correct identification of portion size after receiving in-depth tutorial session and close monitor throughout data collection. The completion of DPC in addition to keeping FR might have been an extra burden for the subjects as fewer caloric intake was recorded when the FR and DPC were completed over the same days. The discrepancy between intake estimates from different dietary assessment methods may have been caused by the omission to duplicate and record or subconscious underconsumption due to participant-perceived burden of completing multiple study tasks.
Degree
Ph.D.
Advisors
Boushey, Purdue University.
Subject Area
Nutrition
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