If you are concerned about keeping your bones healthy and preventing osteoporosis, you'll want to know about the calcium-vitamin D partnership. Vitamin D works hand-in-hand with calcium to build strong bones. Vitamin D helps your body to absorb calcium, and hence helps your bones to stay healthy. Furthermore, Vitamin D improves muscle strength and balance, which may reduce the likelihood of falls and fractures.

What is vitamin D?

Vitamin D is often called the sunshine vitamin, because it is created in our bodies after the skin is exposed to sunlight. It is a fat-soluble vitamin, which means it dissolves in fat; it is also carried and may be stored in body fat. The vitamin D that the body manufactures after sun exposure, or processes from food sources, must be converted to its active form by the liver and then the kidneys.

Why is vitamin D important to my health?

Vitamin D plays a critical role in helping our bodies absorb calcium and other important bone-building minerals like phosphorus. When the level of vitamin D in your blood and fat cells is too low, your body's ability to absorb calcium from food or supplements will decrease, which may affect calcium blood levels.

And calcium is important to more than just bones - all living cells in the body require calcium in order to function. That's why insufficient levels of calcium in the blood trigger the body to "steal" calcium from your bones to bring blood levels back to normal. In fact, the skeleton's original, primitive role is to act as a stored reserve for calcium and phosphorus, to offset shortages of these much-needed minerals.

Osteoporosis occurs when the body withdraws significantly new calcium from its skeletal reserves than it replaces. Because the strength of your bones depends on their mass, or amount of stored calcium, withdrawals from that reserve result in a decrease in bone strength, and increased fragility.

Osteoporosis affects one in four women and one in eight men over the age of 50. Its associated health risks, such as fractures, can result in disability and even death. That's why it's important to ensure that you take in enough of both calcium and vitamin D throughout your life - to build maximum bone mass during the bone building years (up to age 30), and thereafter to avoid the need for major withdrawals from that reserve. Because a large proportion of the population is not getting its calcium requirements, for some, supplementation may be a practical answer.