Everything You Need to Know About the Sun
By Dr. Tamara Dickson
It is nearly impossible to get all necessary Vitamin D from dietary sources. All dietary sources of Vitamin D are animal products like milk, fatty fishes, cod liver oil, egg yolks because Vitamin D is actually a hormone that the body must make, not a vitamin. This poses a problem for people who abstain from eating animal products, all other dietary sources of vitamin D are foods that have Vitamin D added and it is not always added in a form that the body can easily use.
UV-Beta sunlight exposure to skin is needed to turn the pre-hormone dehydrocholesterol into D3, the active form of Vitamin D that the liver can use. It is later processed through the kidneys. UVB rays are reduced by clouds (impairing Vitamin D synthesis greatly for those in the NW), pollution and will not travel through glass. Generally, the best time to catch UV-B rays is midday (10 am-3pm) when UV-A to UV-B ratio is almost equal. This is important because more skin malignancies are caused by UV-A rays. Unfortunately, the UV-B rays are most responsible for sunburn, too, so how does one keep a balance?
Within 10-15 minutes of sun exposure at the ideal times, the average fair-skinned person can synthesize up to 10,000 units of Vitamin D, which is 2-3x greater than the average daily supplementation. It can take an African-Americans up to 60 minutes to make the same amount due to how increased melanin pigment in the skin slows the absorption of UV-B rays. So, I suggest applying sunscreen after your initial 10 minutes of sun exposure so you can synthesize your Vitamin D. Darker skinned individuals can wait up to 15 minutes longer.
Some advice about sunscreen:
-Re-apply sunscreens often. Recent FDA regulations have moved to change labeling such as "water-proof" and "sport-proof" because they mislead consumer into thinking they have more protection than they have.
-Stick to SPF ranges 15-50. Any SPF above 50 has been shown to be no more effective than a 50 and often contain harsher chemical additives.
- Chemical additives to avoid are oxybenzone- a synthetic estrogen and retinyl palmitate- a possible carcinogen.
- Look for active ingredients zinc, titanium, avobenzone or Mexoryl SX. These substances protect skin from harmful UV-A radiation and remain on the skin, with little penetrance into the body.
Dr. Tamara Dickson
Naturopathic Family Medicine
4411 Fremont Ave N
Seattle WA 98103
*Contact Classique Spa for a complimentary consultation where one of our licensed Estheticians will select a sunscreen that's right for your skin type. 206-216-9800