Iodine and vitamin D content and variability in U.S. shell eggs and processed eggs

Authors: ROSELAND, JANET - Consultant; BAHADUR, RAHUL - Consultant; Pehrsson, Pamela

Submitted to: Journal of Food Composition and Analysis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/6/2021
Publication Date: 1/5/2022
Citation: Roseland, J.R., Bahadur, R., Pehrsson, P.R. 2022. Iodine and vitamin D content and variability in U.S. shell eggs and processed eggs. Journal of Food Composition and Analysis. https://doi.org/10.1016/j.jfca.2021.104166.
DOI: https://doi.org/10.1016/j.jfca.2021.104166

Interpretive Summary: The objective was to measure differences among analytical values and variability for iodine and vitamin D in shell eggs and processed eggs, due to public health concerns regarding iodine and vitamin D intake. USDA’s shell egg study obtained representative samples from 24 retail locations in 2019, using statistical plans. Processed (frozen whole) eggs were obtained in 2018 from five major producers (up to 3 lots each; n=14). Sample units were prepared and sent to approved analytical laboratories using validated methods. To monitor accuracy and precision, standard control materials were analyzed. Nutrient means were computed with linear models using appropriate data transformations and compared using t-tests. Vitamin D3 (mean±SE; mcg/100 g) (1.9±0.32) and 25-hydroxyvitamin D3 (0.56±0.04) for shell eggs were not significantly different (p=0.3) than respective values in sampling conducted in 2010. Vitamin D3 and 25(OH)D3 of shell eggs did not differ significantly (p>0.5) from processed eggs. Iodine concentration (mean±SE; mcg/100 g) of 49.2±4.32 was not significantly different (p>0.1) than processed eggs. Agreement of vitamin D data over time, and between egg types, suggests consistent content of eggs. Comparison of shell versus processed egg iodine data suggests consistency. These data contribute valuable information for estimating iodine and vitamin D intakes.

Technical Abstract: Obtaining enough vitamin D and iodine for human health are current U.S. issues. Daily recommended intake for most adults is 150 micrograms iodine and 15 micrograms vitamin D. Eggs are an important source of these nutrients in the U.S. diet. Current egg data are important for measuring the effect of dietary iodine and vitamin D on health. Samples of raw (shell) eggs were obtained from 24 U.S. supermarkets using a statistical sampling plan. Processed (frozen whole) egg samples were obtained from five major companies. Iodine and vitamin D levels were measured at a commercial laboratory using approved methods. Per serving (100 grams), iodine content for shell eggs averaged 49.2 micrograms and vitamin D3 content averaged 1.9 micrograms. No significant difference was seen between values for shell eggs and processed eggs (p>0.05). These data are valuable for clinicians, dietitians and other nutrition scientists who estimate iodine and vitamin D intakes. More research is needed to investigate how seasonality and chicken diets affect iodine and vitamin D content of eggs.