Sun & Vitamin D: A Slightly Different Angle

What are we supposed to do about sun exposure?

There is conflicting information out there regarding those invisible ultraviolet rays from our sun.

How does vitamin D fit in?


UVA rays (the bad guy) have a long wavelength and constitute 90-95% of the sun’s ultraviolet light. They penetrate the furthest into the skin and are the primary inducer of tanning in humans. UVA rays are constant during all hours of daylight the entire year.

UVB rays (the good guy) are partially absorbed by the ozone layer and window glass and have a medium wavelength. They contain more energy than UVA rays and activate the synthesis of vitamin D in the skin. UVB rays are the primary cause of sunburn and of the most concern for skin and eye damage. UVB rays are low in morning and evening and high at midday. UVB rays are influenced by season, the lowest being between November and March.

If you are avoiding the sun by going out early in the morning or late in the day, you’re getting lots of UVA and not much UVB. This practice appears safe on the outside, but greatly interferes with the body’s production of vitamin D.

Safe sunlight exposure (UVB rays) has been shown to protect against as many as 16  types of cancer, including breast, colon, endometrial, esophageal, ovarian, bladder, gallbladder, gastric, pancreatic, prostate, rectal and renal cancers, as well as non-Hodgkin’s lymphoma.

Is our sunlight dangerous? In the northern statesm vitamin D synthesis is greatly decreased because of the seasonal angle of the sun’s rays. They’re too low to efficiently allow UVB radiation to penetrate the atmosphere and activate vitamin D synthesis. This deficiency of vitamin D is of epidemic proportions for the people living in the northern latitudes above the Tropic of Cancer (23.5 degrees).  Redding is at latitude 40.6 degrees.

Do sunscreens really help? Wearing a sunscreen on your uncovered skin blocks your body’s production of vitamin D. In fact, sunscreens reduce vitamin D production by as much as 97.5 to 99.9%. Most chemical sunscreens block UVB rays preventing sunburn but are transparent to UVA rays, the real enemy. Sunscreens are definitely no miracle cure to prevent skin cancer.

Many of us spend our lives indoors or in vehicles, which keeps us from UVB rays that are vital to our body’s production of vitamin D. Here are a few options to protect yourself from vitamin D deficiency:

1. Apply window film to the glass where you spend most of your time. This blocks 99% of the UVA rays that destroy vitamin D and mak you more susceptible to cancer, diseases and influenza. (Visit sunblockersinc.com for more info.)

2. Get 10 – 15 minutes’ exposure from direct sunlight to large portions of your body (between 10 a.m. – 3 p.m.) every day.

3. Contact your doctor to determine if your vitamin D blood levels (25-Hydroxyvitamin D3) are optimal (40-60 ng/ml). A blood spot test from grassrootshealth.org can be ordered for only $40. This will help support your immune system during the influenza season and may prevent and/or treat many cancers and/or diseases.

4. Supplement with vitamin D3. Dosages from 1000 to 5000 IU/day are a reasonable recommendation when you know your vitamin D blood level.


5. The best food source of vitamin D is cod liver oil, since it is difficult in today’s society to get enough vitamin D from our food. Cod liver oil contains more vitamin D per unit weight than any other common food.

6. Limiting sun exposure, wearing protective clothing, and using a non-chemical sunscreen may reduce the risks of skin cancer and other harmful effects of the sun. (Visit mercola.com for non-chemical sunscreen information.)

(mercola.com, articles – Douglas Laboratories, Confronting the Worldwide Epidemic of Vitamin D Deficiency, 10/2008.)

Ed Roberts, DC, spent 12 years as a mechanical engineer on the space shuttle before his chiropractic career in Redding. He has a thriving practice that uses many of the problem-solving skills he used as a NASA engineer to find the cause his patients’ spinal problems. Check out his website at wholefamilychiro.com.

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