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Don Smith · 08-05-2007, 08:44 PM

DNA "damage" is assessed by measuring the photoproducts, i.e., Cyclobutane Pyrimidine Dimers (CPD) and 6-4 dimers (but CPD's are by far the most common and important), that are produced by a dose of UVR. The narrow "peak" of the CPD AS (Action Spectrum) is 300 nm - 302 nm.

Traditional sunlamps have about the same amount of CPD-effective photons as sunlight at noon on a typical summer day while HID/high pressure sunlamps and new-era sunlamps only produce 30% (HID/hp) to 10% (new-era) of sunlight.

As your tolerance to UVR (TUVR) increases, your sensitivty to UVR (SUVR) decreases. An increase in TUVR comes from (a) darker skin type/subtype (darker natural skin color) and (b) the development of facultative (acquired) pigmentation (a.k.a., a "tan"). An increase in TUVR (and a decrease in SUVR) means that you are reducing the potential for DNA damage.

In the October issue of Looking Fit we will show "how and why" your TUVR increases (and your SUVR decreases) in direct relation to (a) your skin type/subtype and (b) your level of tan. Our data shows that a skin type 3B (the most common Caucasian skin subtype) with a "maximum" tan level reduces his SUVR by 90%.

The "bottom line" is that your "best friend" if you want to prevent DNA "damage" is a deep, dark year-round tan (and you get the "fringe" benefit of helping to maintain an optimal vitamin D level and you will look and feel good).

08-05-2007, 08:44 PM	#2 (permalink)
Don Smith Join Date: Feb 25 2000 Location: Tucson, AZ Posts: 1,554 Rep Power: 10	Re: Tan More Less DNA Damage? DNA "damage" is assessed by measuring the photoproducts, i.e., Cyclobutane Pyrimidine Dimers (CPD) and 6-4 dimers (but CPD's are by far the most common and important), that are produced by a dose of UVR. The narrow "peak" of the CPD AS (Action Spectrum) is 300 nm - 302 nm. Traditional sunlamps have about the same amount of CPD-effective photons as sunlight at noon on a typical summer day while HID/high pressure sunlamps and new-era sunlamps only produce 30% (HID/hp) to 10% (new-era) of sunlight. As your tolerance to UVR (TUVR) increases, your sensitivty to UVR (SUVR) decreases. An increase in TUVR comes from (a) darker skin type/subtype (darker natural skin color) and (b) the development of facultative (acquired) pigmentation (a.k.a., a "tan"). An increase in TUVR (and a decrease in SUVR) means that you are reducing the potential for DNA damage. In the October issue of Looking Fit we will show "how and why" your TUVR increases (and your SUVR decreases) in direct relation to (a) your skin type/subtype and (b) your level of tan. Our data shows that a skin type 3B (the most common Caucasian skin subtype) with a "maximum" tan level reduces his SUVR by 90%. The "bottom line" is that your "best friend" if you want to prevent DNA "damage" is a deep, dark year-round tan (and you get the "fringe" benefit of helping to maintain an optimal vitamin D level and you will look and feel good).