Too much vitamin D in food harms dogs

Vitamin D3 is allowed as a feed additive in the EU. It is added to most dog feed mixes as it is considered essential for life. However, too much vitamin D is harmful to animals and therefore maximum levels are set.

A maximum of 2,000 international units (IE) may be contained per kilogram of feed with a moisture content of 12%. For adult dogs, 10IE vitamin D per kilogram of body mass per day is sufficient. If the dog is oversupplied with the vitamin, this can lead to high levels of calcium and phosphorus in the blood, vascular calcification, polyuria, bloody diarrhoea and, in the long term, kidney calcification.