The group continues to recommend that vitamin D is obtained from nutritional sources and dietary supplements rather than the sun, but now says that those who consistently avoid the sun may not be getting enough of the vitamin.
“The vitamin D position statement supports the Academy’s long-held conviction on safe ways to get this important vitamin – through a healthy diet which incorporates foods naturally rich in vitamin D, vitamin D-fortified foods and beverages, and vitamin D supplements,” said David Pariser, president of the American Academy of Dermatology.
“The updated recommendation for individuals who practice daily sun protection acknowledges that while protecting the skin from the damaging rays of the sun is important, so is maintaining adequate vitamin D levels. Concern about vitamin D should not lead people to forego sun protection, but rather prompt a conversation with their physician about how to ensure adequate and safe vitamin D intake while guarding against skin cancer.”
The major function of vitamin D in the human body is the maintenance of blood serum concentrations of calcium and phosphorus by enhancing the absorption of these minerals in the small intestine.
However, although the vitamin is essential in humans, 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.
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.
However, the new position statement from the American Academy of Dermatology emphasizes that the cancer reduction benefits of vitamin D do not yet have sufficient scientific backing.
“Contrary to some reported information about vitamin D and the prevention of certain cancers and diseases – other than for bone health – we simply need more clinical data to determine what role, if any, vitamin D plays in these conditions,” said Dr Pariser.
Others at risk of insufficiency
The Academy also stressed that people with known risk factors for vitamin D insufficiency may need to consume higher doses of the vitamin.
People in this category include those with dark skin, the elderly, photosensitive individuals, people with limited sun exposure, obese individuals or those with fat malabsorption.
The position statement said the standard reference intake levels for vitamin D are those set by the US Institute of Medicine (IOM).
Currently, IOM recommends that children and adults up to age 50 should consume 200 International Units (IU) of vitamin D per day – equivalent to 5μg. Adults aged between 51 and 70 should have an intake of 400 IU (10 μg), and adults aged 71 and over should consume 600 IU (15 μg).
Because high levels of vitamin D can be toxic, IOM has set a tolerable upper intake level (UL) of 1,000 IU per day for infants, and 2,000 IU for children and adults.
“The currently recommended adequate intake levels established by the Institute of Medicine may be revised upward due to evolving research on the increasing clinical benefit of vitamin D,” said the Academy, adding that the US Department of Agriculture (USDA) Dietary Guidelines notes a daily total dose of 1,000 IU of vitamin D for supplementation of those at-risk for vitamin D insufficiency.