Nutrition Science and Everyday Application - beta v 0.1

520 ALICE CALLAHAN, PHD, HEATHER LEONARD, MED, RDN, AND TAMBERLY POWELL, MS, RDN
Figure 9.13. Vitamin D deficiency in children causes rickets, a disease in which inadequate
vitamin D leads to soft, weak, and deformed bones.
In adults, vitamin D deficiency causes osteomalacia, characterized by softening of bones,
reduced bone mineral density, and increased risk of osteoporosis. Because bones are
continuously remodelled throughout the lifespan, inadequate vitamin D limits the calcium
available to continue to rebuild bone tissue. Vitamin D deficiency can also cause bone pain,
as well as muscle weakness and pain, symptoms that can increase the risk of falling and
fractures, particularly in older adults. 2
Although vitamin D toxicity is rare, taking excessive amounts of vitamin D in supplement
form can lead to hypercalcemia, or high blood calcium. Hypercalcemia can cause kidney
damage and calcium deposits to develop in soft tissues such as the kidneys, blood vessels,
or other parts of the cardiovascular system. Synthesis of vitamin D from the sun does not
cause vitamin D toxicity, because vitamin D synthesis is tightly regulated and decreases if the
body has abundant vitamin D.