Current knowledge of vitamin D in dogs

Abstract

There is emerging interest in linking vitamin D status to physiological health and disease states in the dog, as evidenced by the recent increase in publications in this area. This research has most likely been spurred by the studies exploring vitamin D and disease in humans. However, there are important differences in vitamin D intake and metabolism between humans and dogs that should be accounted for. The understanding of basic vitamin D metabolism and the relationship between vitamin D intake and vitamin D status in dogs remains even more limited than current knowledge in humans. This review will summarize current knowledge of vitamin D in the dog, including metabolism and dietary recommendations. Emphasis is placed on the limitations to current knowledge. Studies investigating links between vitamin D and disease will be discussed in light of this knowledge. Suggestions for future research, including the development of reference ranges to define blood vitamin D sufficiency, are provided.

Serum concentrations of lipid‐soluble vitamins in dogs with exocrine pancreatic insufficiency treated with pancreatic enzymes

“…Aside from its well‐established function to regulate calcium availability and bone growth, an increasing number of studies have posited roles for vitamin D beyond calcium regulation. In dogs, inflammatory bowel disease (IBD), chronic cardiac valve disease, and cancer all have been associated with serum 25OHD concentrations lower than those of healthy dogs . Vitamin D concentrations were not significantly different among dogs with EPI, sEPI, and healthy controls.…”

“…Alpha‐tocopherol (vitamin E) is an antioxidant molecule that influences lipid membrane oxidation, inflammation, and immune function . Vitamin D deficiency, determined by assay of 25‐hydrocholecalciferol (25OHD), has been associated with altered calcium homeostasis, oncogenesis, cardiovascular disease, and inflammation …”

Influence of Various Factors on Circulating 25(OH) Vitamin D Concentrations in Dogs with Cancer and Healthy Dogs

“…Decreased blood 25(OH)D concentrations also have been reported in dogs with several other diseases; however, a key limitation shared by many of these studies is that the study designs did not account for other factors that may influence blood 25(OH)D concentrations, such as dietary vitamin D intake. Importantly, little evidence‐based research exists as to which factors may influence blood 25(OH)D concentrations in the dog . Research identifying these factors in healthy dogs and in dogs with disease is needed to inform the design of future studies.…”

“…Importantly, little evidence-based research exists as to which factors may influence blood 25(OH)D concentrations in the dog. 22 Research identifying these factors in healthy dogs and in dogs with disease is needed to inform the design of future studies.…”

25‐Hydroxy vitamin D3 serum concentration in dogs with acute polyradiculoneuritis compared to matched controls

“…Vitamin D is an important regulator of the immune system in both humans and dogs, affecting both the innate and adaptive arms (Cantorna et al . , Cantorna & Mahon , Weidner & Verbrugghe ). Vitamin D decreases Th1/Th17 CD4 + T cells and cytokines, and increases regulatory T cells.…”