Bones need calcium and phosphorus to remain healthy and strong, but the body also needs vitamin D to be able to absorb these two minerals. Without this necessary vitamin, bones can become soft and flexible. This softening is called osteomalacia, or rickets when diagnosed in children. The condition is called osteomalacia when the bone softening occurs after the growth plates have closed.
Rickets was a common childhood illness in North America until the 1940s, when it was discovered that vitamin D, readily available from sunlight (which produces vitamin D in the body) and vitamin D-enriched milk, prevented this condition. Although we haven't seen many cases of rickets in North America over the past 60 years, this condition is beginning to reappear, particularly among exclusively breast-fed babies.
Rickets is still a major childhood problem in poorer, colder countries where babies are kept mainly inside the home and foods rich in vitamin D are not readily available.
Osteomalacia is a disease of bone formation. It is important to differentiate it from osteoporosis, which is a disease of bone that is already formed.