Vitamin D and osteoporosis are related because vitamin D is necessary for the body to build healthy bones. In osteoporosis, bones steadily lose calcium and become progressively weaker. Although osteoporosis doesn't usually cause noticeable symptoms, it greatly increases the risk of fractures. Evidence indicates that adequate vitamin D and calcium intake can help prevent osteoporosis from developing. Vitamin D is probably less effective at treating osteoporosis once it has already begun to weaken bones.
While calcium is rightly associated with building strong bones, the body can't make effective use of dietary calcium without vitamin D. Vitamin D is needed to absorb the calcium in food so that it can be used by the body to increase bone mass, which strengthens bones. The connection between vitamin D and osteoporosis risk can generally be described as an inverse relationship. As vitamin D intake approaches recommended levels, developing the condition becomes less likely.
Although vitamin D and osteoporosis are certainly related, it is not clear how much of a factor vitamin D is in the risk for developing the condition. It is thought that osteoporosis risk is mostly mostly due to genetics, and perhaps 40 percent is due to other factors that individuals can control, like diet and exercise. Still, vitamin D intake as measured by blood levels has been found to have a clear connection to overall bone health and strength. In spite of this knowledge, many otherwise healthy people in developed countries have been found to have low levels of vitamin D. Older people are more likely to be deficient in vitamin D, probably because aging bodies lose some of their ability to absorb nutrients through digestion.
Another connection between vitamin D and osteoporosis is that vitamin D can help improve balance in older people, leading to fewer falls. In elderly people with osteoporosis, falls can cause serious injuries like broken hips or possibly death. Vitamin D taken with calcium reduces the chance of falls even further.
Bone mass begins to decrease in both genders after about the age of 35, so people more than 35 years of age may wish to take vitamin D supplements. Cold-water fish are a good source of dietary vitamin D, and the skin also naturally makes this vitamin when exposed to sunlight. Certain activities can make positive use of the relation between vitamin D and osteoporosis. An outdoor activity like walking can encourage the body's natural production of vitamin D and also promote healthy bones through exercise.