Calcium, vitamin D, and bone health

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In Australia, we are very fortunate to be exposed to long days with lots of sunshine which provides us with healthy doses of vitamin D, as long as we don’t stay in the sun for too long and get burnt.

Vitamin D has a very important role in the body, and although there are many foods which are rich in vitamin D, such as fatty fish, seaweed, fortified foods, mushrooms, egg yolks, and organ meats, although the sun remains the best and most available source to us. Up to 15 minutes with skin exposure in the winter is sufficient, and in summer, when the UV exposure is higher, incidental activity for a few minutes will provide sufficient vitamin D. Although sun protection reduces that amount of vitamin D we can absorb, sun protection is of vital importance to reduce the risk of skin cancer.

After we absorb vitamin D through our skin, it is converted in our bodies to an active form which helps the body to absorb calcium, which contributes to having healthy bones. Vitamin D’s major role is to regulate calcium and phosphorus levels in the blood, which assists in contributing to bone health. Vitamin D may also protect against osteoporosis, high blood pressure, cancer, and other diseases.

Calcium is found in highest amounts in dairy foods, but is also in high quantities in fish with bones, spinach, other green leafy vegetables, and in nuts and seeds. It is an important nutrient for bone building and slowing the rate of bone loss. It is important to consume adequate calcium each day, which varies depending on age, to prevent the body from taking calcium from the bones to assist the other functions of the body. As we age, the intestines do not absorb calcium as well, and the kidneys allow more to pass into the urine.

Age-related osteoporosis is assumed to be a common part of ageing, but does not have to be a normal part of ageing. Ensuring adequate calcium and having adequate vitamin D exposure prior to 30 years old when peak bone density is achieved ensures that bones are as strong as possible long term. If you are concerned about your calcium or vitamin D intake, please see one of our Accredited Practising Dietitians for individualised advice.