Does taurine deficiency cause metabolic bone disease and rickets in polar bear cubs raised in captivity?

Adv Exp Med Biol. 2009;643:325-31. doi: 10.1007/978-0-387-75681-3_33.


Rickets and fractures have been reported in captive polar bears. Taurine (TAU) is key for the conjugation of ursodeoxycholic acid (UDCA), a bile acid unique to bears. Since TAU-conjugated UDCA optimizes fat and fat-soluble vitamin absorption, we asked if TAU deficiency could cause vitamin D malabsorption and lead to metabolic bone disease in captive polar bears. We measured TAU levels in plasma (P) and whole blood (WB) from captive and free-ranging cubs and adults, and vitamin D3 and TAU concentrations in milk samples from lactating sows. Plasma and WB TAU levels were significantly higher in cubs vs captive and free-ranging adult bears. Vitamin D in polar bear milk was 649.2 +/- 569.2 IU/L, similar to that found in formula. The amount of TAU in polar bear milk is 3166.4 +/- 771 nmol/ml, 26-fold higher than in formula. Levels of vitamin D in bear milk and formula as well as in plasma do not indicate classical nutritional vitamin D deficiency. Higher dietary intake of TAU by free-ranging cubs may influence bile acid conjugation and improve vitamin D absorption.

MeSH terms

  • Animals
  • Bone Diseases, Metabolic / etiology*
  • Chromatography, High Pressure Liquid
  • Milk / chemistry
  • Rickets / etiology*
  • Taurine / analysis
  • Taurine / deficiency*
  • Ursidae
  • Vitamin D / analysis


  • Vitamin D
  • Taurine