Contributions of Sunlight and Diet to Vitamin D Status

Contributions of Sunlight and Diet to Vitamin D Status.

Calcif Tissue Int. 2012 Sep 22.

Macdonald HM.

Musculoskeletal Research, Health Sciences Building, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK, h.macdonald@abdn.ac.uk.

Vitamin D is made in the skin using ultraviolet radiation of specific low wavelength, 290-315 nm (UVB).

For many parts of the world there is a period when there is insufficient intensity of UVB to make vitamin D, which is reflected by a clear seasonal variation in vitamin D status.

Sun avoidance practices, melanin in pigmented skin, and sun protection creams (sunscreen), if used properly, can dramatically reduce vitamin D synthesis.

Few foods naturally contain vitamin D, although some countries fortify foods with vitamin D.

Regulatory mechanisms in the skin mean there is no danger of vitamin D toxicity through sunlight synthesis.

Although oral vitamin D is potentially toxic with high-dose supplements, there is a wide safety margin.

Long-term safety data covering a range of potential adverse outcomes are limited.

PMID: 23001438

Longer shadow = higher risk of cancer

Vitamin D from sun and food during 4 seasons in the UK

NOTE: Surrey is near London (Dark Brown), Aberdeen is far North (white)

PDF which was available to the public Dec 2012 is attached at the bottom of this page

See also VitaminDWiki

• No – 10 minutes per day of sun-UVB is NOT enough

• All items in Noontime Sun items

• All items in Food Sources of Vitamin D items

• vitamin D content in foods - 2002

• 80 percent of vitamin D from sun rather than from food – Nov 2010 same author

• Actual vitamin D intake just 200 IU daily - 2010