Brief communication: New method for measuring nitrogen isotopes in tooth dentine at high temporal resolution.

OBJECTIVES: Nitrogen isotopes (δ15N) are widely used to study human nursing and weaning ages. Conventional methods involve sampling 1-mm thick sections of tooth dentine-producing an averaging effect that integrates months of formation. We introduce a novel protocol for measuring δ15N by multicollector secondary ion mass spectrometry (SIMS). MATERIALS AND METHODS: We sampled dentine δ15N on a weekly to monthly basis along the developmental axis in two first molars of healthy children from Australia and New Zealand (n = 217 measurements). Nitrogen isotope ratios were determined from measurements of CN- secondary molecular ions in ~35 µm spots. By relating spot position to enamel formation, we identified prenatal dentine, as well as sampling ages over more than 3 years. We also created calcium-normalized barium and strontium maps with laser ablation-inductively coupled plasma-mass spectrometry. RESULTS: We found rapid postnatal δ15N increases of ~2‰-3‰, during which time the children were exclusively breastfed, followed by declines as the breastfeeding frequency decreased. After weaning, δ15N values remained stable for several months, coinciding with diets that did not include meat or cow's milk; values then varied by ~2‰ starting in the third year of life. Barium did not show an immediate postnatal increase, rising after a few months until ~1-1.5 years of age, and falling until or shortly after the cessation of suckling. Initial strontium trends varied but both individuals peaked months after weaning. DISCUSSION: Developmentally informed SIMS measurements of δ15N minimize time averaging and can be precisely related to an individual's early dietary history.

A Qualitative Analysis of Eating Behaviors Among Food Insecure College Students.

OBJECTIVE: To explore (1) how the cycle of food availability impacts food insecure college students' food-coping behaviors and (2) how access to a campus food pantry impacts food availability. METHODS: Qualitative, semistructured one-on-one interviews via Zoom were transcribed verbatim. Three investigators performed content analysis to identify and compare themes among participants with and without access to a campus food pantry. RESULTS: Forty undergraduate students from Illinois 4-year institutions with (n = 20) and without (n = 20) campus food pantries discussed similar experiences related to their food situation, eating behaviors, and use of resources, resulting in 7 themes: unique challenges of the college environment, childhood experiences, the impact of food insecurity, mental energy, the spectrum of resource management, structural barriers, and hiding hunger. CONCLUSIONS AND IMPLICATIONS: Food insecure students may use coping mechanisms to manage food and resources. The existence of a campus food pantry alone is insufficient to meet the needs of these students. Universities could consider providing additional support (ie, free meals), advertising available resources, or integrating food insecurity screening into other established processes.

Exploration of Dietetics Graduate Students' Experience in a Flipped Course Using Learning Reflections.

OBJECTIVE: Evaluate graduate students' experience in a flipped metabolism course using periodic learning reflections. METHODS: Two cohorts of graduate students (n = 17, total) were recruited from an advanced metabolism course using a flipped learning approach during the fall 2016 and 2017 semesters. After course completion, 2 investigators used content analysis to develop themes from 8 structured learning reflections. RESULTS: Four themes were developed from the reflections: responsibility for learning, metacognition, team-based learning, and transfer of skills. Resistance to flipped learning peaked at week 4 of the semester. By the end of the semester, students seemed to embrace the flipped approach and self-directed learning. CONCLUSIONS AND IMPLICATIONS: Despite reporting being better self-directed learners by the end of the semester, students may struggle with the flipped learning format early in the semester. Thus, instructors may need to adopt supportive techniques with students initially.

Development of the Health and Weight Attitudes Scale.

OBJECTIVE: To develop and validate an instrument to assess attitudes toward Health at Every Size (HAES) principles. METHODS: Survey items were generated based on 5 HAES principles. A panel of reviewers was recruited to establish content validity. A convenience sample of college students in health education was recruited for pilot survey administration. Internal reliability was assessed using Cronbach α and test-retest reliability was assessed with Pearson correlation. RESULTS: Three panelists reviewed the instrument and provided feedback for revision. Cronbach α for the final instrument was .75 (n = 43) at pretest and .78 (n = 53) at posttest, and Pearson correlation was 0.85 (n = 39), indicating internal consistency and test-retest reliability. CONCLUSIONS AND IMPLICATIONS: The instrument was determined to be both a valid and reliable instrument to measure HAES attitudes among college students in health education. Nutrition educators may find this instrument useful in other settings to assess HAES attitudes or as an alternative to other instruments measuring anti-fat attitudes.