Sun exposure: Is just a little bit enough?
January 16, 2013 -- John Cannell, MD
Some experts opine that brief sun exposure will supply all the vitamin D that one needs. However, there has never been a study of how much vitamin D such exposure generates.
Recently, researchers in Korea decided to find out. Dr. Sang-Hoon Lee and colleagues from the Ajou University School of Medicine in South Korea studied the effect of brief sun exposure on vitamin D levels in 20 young women for four weeks.
Lee SH, Park SJ, Kim KM, Lee DJ, Kim WJ, Park RW, Joo NS. Effect of sunlight exposure on serum 25-hydroxyvitamin d concentration in women with vitamin D deficiency: using ambulatory lux meter and sunlight exposure questionnaire. Korean J Fam Med. 2012 Nov;33(6):381-9.
The study was conducted between October and November at latitude 37 degrees north, about the latitude of Washington DC. Initial mean 25(OH)D levels were 11 ng/ml and no woman had levels greater than 20 ng/ml to begin the study. The women were told to get 20 minutes of midday sun exposure on their hands, forearms and face every weekday for four weeks. Facial sunblock and sunglasses were permitted.
Guess how much 25(OH)D levels increased after a month of daily sun exposure? Vitamin D levels did not increase at all; in fact, they were a little lower than when the study began!
Why? I think four reasons may explain the finding. Continue reading → (no membership required) Vitamin D status of exclusively breastfed infants
January 20, 2013 -- John Cannell, MD
Researchers at the University of Auckland recently found that vitamin D deficiency is quite common in exclusively breastfed infants in New Zealand. Continue reading → (membership required) Vitamin D: Most popular vitamin of 2012
January 19, 2013 -- Dr William Grant
There were 3,600 papers published about vitamin D in 2012. Dr Grant summarizes the top 16 vitamin D papers of this past year. Continue reading → (no membership required) Does vitamin D prevent formation of blood clots?
January 17, 2013 -- John Cannell, MD
Researchers at the Copenhagen University Hospital in Denmark obtained vitamin D levels on more than 18,000 patients to find out if there is a link between D deficiency and blood clots. Continue reading → (membership required)
Vitamin D deficiency prevalent in autoimmune skin disorder
January 15, 2013 -- Kate Saley
Researchers in Egypt report a link between vitamin D deficiency and vitiligo, an autoimmune skin disease characterized by loss of pigmentation (brown color) from areas of the skin. Continue reading → (membership required) Calcium, magnesium levels linked to lung cancer risk?
January 18, 2013 -- John Cannell, MD
Researchers at Vanderbilt University School of Medicine recently studied calcium and magnesium intakes and incidence of lung cancer in 71,000 Chinese women. Continue reading → (no membership required)
Treatment of D deficiency: Oral supplement or vitamin D3 injection?
January 16, 2013 -- Vitamin D Council News
Researchers recently conducted a randomized controlled trial assessing the effectiveness and practicality of oral vitamin D supplements compared to intramuscular vitamin D supplement injections in the treatment of vitamin D deficiency. Continue reading → Dr Michael Holick: What does the sun do for me?
January 22, 2013
Are you ready for the second Grassroots Health webinar?
Today at 10am PST Dr Michael Holick will be discussing the question: "What does the sun do for me?"
Register here for today's webinar! Have a vitamin D question? You can submit your questions for Dr Holick when you register.