10.17 : Role of Vitamins in Maintaining Bone Health

The growth and maintenance of bone are regulated by a combination of nutritional factors, including vitamins, such as vitamin A, B₁₂, C, D, and K.

Vitamin A

Vitamin A is involved in the process of bone remodeling. Retinoic acid, the active metabolite of Vitamin A, has nuclear receptors in osteoblasts and osteoclasts, which are involved in bone remodeling.

Vitamin B₁₂

Vitamin B₁₂ acts as a cofactor during the formation of osteoblast-related proteins, such as osteocalcin. Vitamin B₁₂ plays a role in iron metabolism, which is involved in bone formation.

Vitamin C

Vitamin C is a cofactor for enzymes required to maintain a stable triple-helical conformation of collagen. Also, vitamin C stimulates the activity of the enzyme alkaline phosphatase. This enzyme is a marker for osteoblast formation and helps in bone mineralization.

Vitamin D

Calcium cannot be absorbed from the small intestine without vitamin D. Insufficiency of vitamin D is therefore linked to osteoporosis, which can be associated with an increased risk of fractures.

Vitamin K

Vitamin K is necessary for the γ-carboxylation of osteocalcin, the principal non-collagenous protein of bone. Specifically, vitamin K is a cofactor of γ -carboxylase, an enzyme involved in γ -carboxylation of glutamic acid residues in proteins, including osteocalcin. Carboxylated osteocalcin helps in the mineralization of the bone matrix.

This text is adapted from Openstax, Anatomy and Physiology 2e, Section 6.6: Exercise, Nutrition, Hormones, and Bone Tissue.