Effect of Vitamin D-biofortified Eggs on Wintertime Serum 25-hydroxyvitamin D in Adults: Randomized Controlled Trial

Inclusion Criteria: \- consenting white men and women aged 45-70 years Exclusion Criteria: * consumption of vitamin D-containing supplements throughout the study. planning to take a winter vacation (during the course of the 8-wk intervention) - to a location at which either the altitude or the latitude would be predicted to result in significant cutaneous vitamin D synthesis from solar radiation * planning to use tanning facilities of any type. * a severe medical illness, * allergy to egg products, * medically advised to limit egg intake in relation to managing hypercholesterolemia, * hypercalcaemia, * known intestinal malabsorption syndrome, * excessive alcohol use, * the use of medications known to interfere with vitamin D metabolism