Breakfast Skipping Is Associated with Vitamin D Deficiency, But Not Iron Deficiency, Among Military Recruits Entering Initial Military Training

Abstract Objectives Vitamin D deficiency (VDD) and iron deficiency (ID) are associated with injury risk and performance, respectively, in military recruits during initial military training (IMT). Breakfast skipping is prevalent among young adults and contributes to decreased intakes of vitamin D and iron. However, whether breakfast skipping is associated with VDD and ID in military recruits, and whether the mandatory breakfast attendance required in IMT mitigates VDD and ID is unknown. Methods Army, Air Force, and Marine recruits (N = 2117, 42% male, mean ± SD age 21 ± 4y) completed a food frequency questionnaire pre-IMT, and provided blood samples pre- and post-IMT. Breakfast skipping was self-reported and defined as skipping breakfast ≥3 d/wk pre-IMT. Diet quality was determined by Healthy Eating Index. ID was defined as meeting ≥2 of the following: serum ferritin <12 ng/mL, transferrin saturation <16%, red blood cell distribution width >15%. VDD was defined as serum 25-hydroxyvitamin D (25OHD) <20 ng/mL. Associations between breakfast skipping, VDD, ID, vitamin D intake, and diet quality were determined by multivariate-adjusted logistic and linear regression. Mediation models tested whether diet quality and vitamin D intake mediated associations between breakfast eating and VDD. Results 50% of military recruits were classified as breakfast skippers pre-IMT. Breakfast skipping was associated with increased odds of VDD pre-IMT (OR 1.6, 95% CI 1.1–2.2). Diet quality and vitamin D intake were partial mediators, with breakfast skipping indirectly increasing odds of VDD through lower diet quality and lower vitamin D intake pre-IMT (OR 1.1, 95% CI 1.0–1.2; OR 1.2, 95% CI 1.1–14, respectively). There were no associations between habitual breakfast skipping and pre-IMT ID or pre- to post-IMT change in VDD, 25OHD concentrations, diet quality, or vitamin D intake. Conclusions Breakfast skipping is prevalent among incoming military recruits and is associated with increased odds of VDD due in part to lower diet quality and vitamin D intake. However, mandatory breakfast during IMT may not differentially impact changes in vitamin D status or intake in pre-IMT breakfast skippers relative to pre-IMT breakfast eaters. Funding Sources US Army MRDC. Authors’ views do not reflect official DoD or Army policy.