Whole Egg Consumption as a Dietary Prevention and Treatment Intervention Increases Serum 25‐hydroxyvitamin D Concentrations in Rats with DSS‐Induced Colitis
Authors: Jones Samantha K , Reed Carter H , Hahn Kaylee E , Coonts Caitlyn A , Worrall Deanna M , Rowling Matthew J , Schalinske Kevin L 
Published: November 2023

Research has shown that inflammatory bowel disease (IBD) results in a vitamin D deficient condition. Moreover, studies also suggest that vitamin D deficiency may play a role in both the pathogenesis and progression of IBD. Thus, the aim of this study was to investigate the ability of a diet containing whole egg to maintain vitamin D homeostasis in rats with dextran sodium sulfate (DSS)‐induced colitis. Because eggs are an excellent source of vitamin D, particularly 25‐(OH)‐vitamin D3 (25D), they represent a viable dietary strategy to maintain vitamin D balance during colitis progression. Five week‐old Sprague‐Dawley rats (N=54) were randomly assigned to 3 diet groups: a control AIN93 casein‐based diet, the same diet containing whole egg in place of casein, or a casein‐based diet with supplemental cholecalciferol (i.e., vitamin D3) at the same total vitamin D concentration (37.6 mg/kg diet) provided by the whole egg‐based diet. All diets were formulated to provide 20% (w/w) protein; thus, it required addition of corn oil to the casein‐based diets to achieve the same total lipid content as the whole egg‐based diet. The study was divided into a 6 wk pre‐DSS period and a 6 wk post‐DSS period, where tap water was replaced by 3.5% DSS‐treated drinking water for 7 d. Rats in the pre‐DSS treatment period were fed their respective diets prior to DSS administration: casein‐based (n=30), casein supplemented with D3 (n=12), or whole egg‐based (n=12). Of the 30 rats fed casein only, 24 received DSS drinking water as well as half of the rats in the supplemental D3 and whole egg groups. All but 18 of the casein‐fed rats were sacrificed after the 7 d DSS administration. Following 7 d of DSS consumption, the 18 post‐DSS treatment rats were divided into the same 3 dietary treatment groups for the final 6 wk. For all rats at all time points, food and water were provided ad libitum. Prior to sacrifice, animals were placed in metabolism cages for 12 h for the collection of urine and to ensure they were in a fasted state. Pre‐treatment control and DSS‐treated rats fed the whole egg‐based diet had serum 25D concentrations that were 78% higher than rats fed the casein‐based diets (P<0.001). However, D3 supplementation was without effect on serum 25D concentrations regardless of IBD status (P = 0.996). Similar patterns were observed in the post‐treatment period. Rats whose diet was changed to whole egg after DSS‐administration had serum 25D concentrations that were 74% higher than rats fed casein and supplemental D3 (P<0.008). These data strongly suggest that dietary consumption of whole egg results in: (1) an increase in serum 25D concentrations in control and IBD rats; and (2) increased serum 25D concentrations that were greater than an equivalent amount of supplemental D3. These results may support new dietary recommendations regarding whole egg consumption as a viable prevention and treatment strategy for the management of vitamin D deficiency in IBD.

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Egg Nutrition Center, Park Ridge, IL.