In a recent position statement on vitamin D, the academy stressed the importance of obtaining adequate levels of the vitamin without overexposure to cancer-causing UV radiation from sunlight or tanning machines.
"Vitamin D is essential for optimal health, and the medical literature supports safe ways to get it - a healthy diet which incorporates foods naturally rich in vitamin D, vitamin D-fortified foods and beverages, and vitamin D supplements," said dermatologist C William Hanke, MD, president of AAD.
“And, according to the medical literature, unprotected exposure to UV radiation from sunlight (natural) or indoor tanning devices (artificial) is not safe. Individuals who intentionally expose themselves to UV radiation for vitamin D are putting their health at risk for developing skin cancer."
AAD said it supports the recommended daily intake levels provided in guidelines from the Institute of Medicine (IOM), and is urging physicians to do the same.
Currently, IOM recommends that children and adults up to age 50 should consume 200 International Units (IUs) of vitamin D per day – equivalent to 5μg. Adults aged between 51 and 70 should have an intake of 400 IUs (10 μg), and adults aged 71 and over should consume 600 IUs (15 μg).
AAD noted, however, that these recommendations may be revised upward due to evolving research on the increasing clinical benefits of vitamin D.
Indeed, IOM told NutraIngredients-USA.com last week that it has started a review of all science on Vitamin D, with a view to updating recommended intake levels.
The review is being sponsored by the US National Institutes of Health (NIH) and Health Canada, with a final report estimated to be complete in spring 2010.
Just last month, the American Academy of Pediatrics (AAP) issued a report stating that children should be consuming double the usually recommended levels of vitamin D - 400 International Units (IUs) of the vitamin per day, compared to the 200 IUs previously recommended by AAP.
And in recent weeks, a group of 18 scientists from the University of California said recommended daily intakes of vitamin D should be raised to 2,000 International Units for vitamin D3.
Vitamin D refers to two biologically inactive precursors - D3, also known as cholecalciferol, and D2, also known as ergocalciferol. The former, produced in the skin on exposure to UVB radiation (290 to 320 nm), is said to be more bioactive.
Both D3 and D2 precursors are hydroxylated in the liver and kidneys to form 25- hydroxyvitamin D (25(OH)D), the non-active 'storage' form, and 1,25-dihydroxyvitamin D (1,25(OH)2D), the biologically active form that is tightly controlled by the body.
Previously, experts have noted that about one billion people are estimated to be vitamin D deficient, even more so since very few foods are fortified with the vitamin.
In adults, it is said vitamin D deficiency may precipitate or exacerbate osteopenia, osteoporosis, muscle weakness, fractures, common cancers, autoimmune diseases, infectious diseases and cardiovascular diseases. There is also some evidence that the vitamin may reduce the incidence of several types of cancer and type 1 diabetes.