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Sun: The Natural Source of Vitamin D

Thursday, February 02, 2012

Sunlight is the light of life. It's as important as air and water and it'is the best source of Vitamin D. We all need 10-15 minutes a day of sun on as much skin as we can legally get away with exposing, while wearing our sun glasses.  

Dr. Michael Holick, one of the foremost Vitamin D experts, estimates that vitamin D deficiency is the most common medical condition in the world.  John Cannell, MD, the Executive Director of the Vitamin D Council has been quoted as saying, “Humans make thousands of units of self-limiting Vitamin D within minutes of whole body exposure to sunlight. From what we know of nature, it is unlikely such a system evolved by chance.”

Dr. Frank Lipman, internationally recognized expert in the fields of Integrative and Functional Medicine and a practicing physician says, “For hundreds of thousands of years, man has lived with the sun: our ancestors were outdoors far more often than indoors. We developed a dependence on sunshine for health and life, so the idea that sunlight is dangerous does not make sense. How could we have evolved and survived as a species, if we were that vulnerable to something humans have been constantly exposed to for their entire existence?” 

There are only two ways to receive vitamin D in the amounts necessary for health. UVB exposure from sunlight and vitamin D supplementation:


Since this is the way nature intended, it should be considered the method of choice. Vitamin D synthesis occurs faster in individuals with fair skin, the darker the skin the longer it takes for sun on skin to produce vitamin D.  According to the Vitamin D Council, sunscreen with an SPF as low as 8 can block as much as 95% of vitamin D production. 

New Adequate Daily intake (AI) for vitamin D

Children and adults up to the age of 70 years – 600 IU
Seniors 70+ years – 800 IU

Most vitamin D researchers think these amounts are inadequate since these recommendations are based solely on vitamin D and bone health studies. Vitamin D influences a much wider array of physiological processes than simply maintaining bone health and normal calcium metabolism.  They suggest that for proper functioning, a healthy human body utilizes around 3,000-5,000 IU of vitamin D per day, indicating the current recommended intakes are not high enough to raise and / or maintain the vitamin D levels necessary for optimal health.

The US Government tolerable Upper Intake Level (Ul) for vitamin D has recently been increased from 2,000 IU per day to 4,000.  This is an improvement but still may be on the low side, given all of the recent science, particularly for those with extra weight or who are obese.

The self-limiting amount produced by sun on skin seems to be about 10,000 IU per day.

Supplemental vitamin D comes in two forms: cod liver based oil and dry powder lanolin-based water-soluble vitamin D.  As far as we know, both are equally absorbed and metabolized by the body.  Vitamin D3 is the type of vitamin D the body naturally produces from sun exposure on skin therefore the type used in most vitamin D supplements.  Vitamin D2 is produced naturally from yeast and is not as readily absorbed.

Vitamin D and Weight Gain

Recent studies link vitamin D deficiency to weight gain and all of the degenerative diseases associated with excess weight, including diseases of the eye. 

Ellen Troyer, MT MA
Biosyntrx CEO / Chief Research Officer



My tan has faded and The Royal Hawaiian Eye Meeting is now a cherished education memory.  The good news is that a week of appropriate amounts of sun on skin was good for both physical and mental health. 

I'm sitting at my desk in Colorado watching a beautiful snow storm blow over Cheyenne Peak, which is putting a big smile on the faces of all skiers. The Western mountains have not had a lot of snow this season and more good news is that the sun will come back tomorrow - or the next day, as it does in the Rockies.    

Enjoy the coming weekend and spend some time playing outside.   It will make you happy.

FYI: Vitamin D deficiency has been linked to a higher risk of developing AMD, so Biosyntrx Macula Complete multiple includes 2,000 IU of vitamin D3, our less potent multiple, Oculair, includes 1,200 IU of vitamin D3 and our dry eye formulation, BioTears, includes 168 IU of vitamin D from cod liver oil - per suggested daily dose.   


Clinical references available in the Biosyntrx office.