Vitamin D (cholecalciferol / D3) is an essential fat-soluble vitamin in pet food required for calcium-phosphorus homeostasis and bone health. Dogs and cats, unlike humans, cannot synthesize enough vitamin D from sunlight, so dietary intake is mandatory. Excess intake can cause severe toxicity such as hypercalcemia and soft tissue calcification.
| Active Form | Calcitriol (1,25-dihydroxy D3) |
| Solubility | Fat-soluble (toxicity risk) |
| Dog Requirement | 500 IU/kg DM (AAFCO min.) |
| Cat Requirement | 280 IU/kg DM (AAFCO min.) |
| Safe Upper Limit | 3000 IU/kg DM (dog) |
| Controversy Level | Moderate (Toxicity) |
Vitamin D is an essential nutrient and all complete foods should provide it adequately. Because sunlight synthesis is insufficient in dogs and cats, dietary supply is mandatory. In balanced formulas, vitamin D is usually maintained in a safe range. Extra supplementation should only be considered under veterinary supervision.
Functions
- Calcium absorption: Increases intestinal absorption of calcium and phosphorus
- Bone mineralization: Supports osteoblast activity and bone density
- Immunity: Has immunomodulatory effects
- Muscle function: Helps regulate calcium for muscle contraction
Vitamin D Toxicity
Vitamin D toxicity is a life-threatening condition. Hypercalcemia can lead to kidney failure, cardiac arrhythmias, and soft tissue calcification. Multiple pet foods were recalled in the United States in 2018-2019 because of excessive vitamin D. Additional vitamin D should never be used without veterinary oversight.
Related VetKriter Tools
References
- NRC (National Research Council). (2006). Nutrient Requirements of Dogs and Cats. National Academies Press.
- Mellanby, R. J. (2016). Beyond the skeleton: The role of vitamin D in companion animal health. Journal of Small Animal Practice, 57(4), 175-180.