I’m worried that I might not be getting enough vitamin D. How much do i need?
with Dr Marc
Vitamin D is a critically important hormone that is required for healthy bones and maintaining blood calcium levels and supporting the immune system. Vitamin D also prevents osteoporosis, depression, many forms of cancer and acts to reduce blood pressure. A very small amount of vitamin D is obtained in the diet from oily fish but the vast majority is produced by the skin on exposure to ultraviolet (UVB) radiation from natural sunlight.
You need direct sun exposure to the skin to produce Vitamin D and even weak sunscreens (SPF=8) or glass will block the skin’s Vitamin D production and many people are vitamin D deficient due to our modern indoor lifestyles and overuse of sunscreens. However, it is not necessary to bake in the sun to build your Vitamin D levels. Exposure of the hands, face and arms for around 10 minutes a few times a week will ensure you produce sufficient Vitamin D. It is advisable to get sun exposure in the early morning or late afternoon and to limit prolonged sun exposure and exposure in the middle of the day in summer to avoid sunburn and sun damage.
Despite our climate, many Australians don’t get enough casual exposure to the sun to produce adequate amounts of Vitamin D. This is particularly true for elderly people, people who avoid the sun due to skin conditions and people with dark skin. Once produced in the skin, Vitamin D needs to be activated by the kidneys and liver to form the active form called calcitriol, so people with diseases of these organs are at risk of Vitamin D deficiency. If adequate sun exposure is not possible, a vitamin D supplement of at least 400 IU (10 μg) per day is recommended.