On facebook.com I'm a members of the USANA ~ Sense Beautiful Science Information Group. This group has been created by Marie Bertrand, a microbiologist and skin scientist who sends us updates on skin and skin care. Today she sent us a message about parabens, sun exposure and their danger to our skin. Below is the message-hope it inlightens you as it did me.
Good evening,
I just came across a VERY interesting article about a type of paraben (methylparaben, or MP) frequently used in cosmetic formulations.
This article, recently published in a highly respected scientific journal, Chemical Research in Toxicology, says that "Light irradiation sometimes produces unexpected activity from chemicals such as MP" producing "2 major photo-products" including one that might "cause skin damage involving carcinogenesis through the combined activation of sunlight irradiation and skin [enzymes]".
It is well known in dermatology that methylparaben (MP) easily penetrates the dead skin cell layer (stratum corneum) to reach the living cells of the epidermis. Since the majority of us are somehow exposed to the sun on a daily basis (and yes, that car ride to work counts, as UVAs go through glass even if it's cloudy outside), this finding could be quite alarming.
It is well known in dermatology that methylparaben (MP) easily penetrates the dead skin cell layer (stratum corneum) to reach the living cells of the epidermis. Since the majority of us are somehow exposed to the sun on a daily basis (and yes, that car ride to work counts, as UVAs go through glass even if it's cloudy outside), this finding could be quite alarming.
For those of you who are interested in further details, I have included below the abstract related to this article, as published online by PubMed.
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Chem Res Toxicol. 2008 Aug;21(8):1594-9.
COMBINED ACTIVATION OF METHYL PARABEN BY LIGHT IRRADIATION AND ESTERASE METABOLISM TOWARD OXIDATIVE DNA DAMAGE.
Chem Res Toxicol. 2008 Aug;21(8):1594-9.
COMBINED ACTIVATION OF METHYL PARABEN BY LIGHT IRRADIATION AND ESTERASE METABOLISM TOWARD OXIDATIVE DNA DAMAGE.
Okamoto Y, Hayashi T, Matsunami S, Ueda K, Kojima N.Faculty of Pharmacy, Meijo University, 150 Yagotoyama, Tempaku-ku, Nagoya 468-8503, Japan.
Methyl paraben (MP) is often used as a preservative in foods, drugs, and 
cosmetics because of its high reliability in safety based on the rapid excretion and nonaccumulation following administration. Light irradiation sometimes produces unexpected activity from chemicals such as MP; furthermore, there is ample opportunity for MP to be exposed to sunlight. Here, we investigated whether MP shows DNA damage after sunlight irradiation. Two major photoproducts, p-hydroxybenzoic acid (PHBA) and 3-hydroxy methyl paraben (MP-3OH), were detected after sunlight irradiation to an aqueous MP solution. Both photoproducts were inactive in the in vitro DNA damage assay that measures oxidized guanine formed in calf thymus DNA in the presence of divalent copper ion, a known mediator of oxidative DNA damage. Simulated MP metabolism using dermal tissues after light irradiation produced these two photoproducts, which reacted with a microsomal fraction (S9) of the skin. A metabolite from MP-3OH, not PHBA, caused distinct DNA damage in the in vitro assay. This active metabolite was identified as protocatechuic acid, a hydrolyzed MP-3OH product. In addition, NADH, a cellular reductant, enhanced DNA damage by approximately five times. These results suggest that reactive oxygen species generated by the redox cycle via metal ion and catechol autoxidation are participating in oxidative DNA damage. This study reveals that MP might cause skin damage involving carcinogenesis through the combined activation of sunlight irradiation and skin esterases.
cosmetics because of its high reliability in safety based on the rapid excretion and nonaccumulation following administration. Light irradiation sometimes produces unexpected activity from chemicals such as MP; furthermore, there is ample opportunity for MP to be exposed to sunlight. Here, we investigated whether MP shows DNA damage after sunlight irradiation. Two major photoproducts, p-hydroxybenzoic acid (PHBA) and 3-hydroxy methyl paraben (MP-3OH), were detected after sunlight irradiation to an aqueous MP solution. Both photoproducts were inactive in the in vitro DNA damage assay that measures oxidized guanine formed in calf thymus DNA in the presence of divalent copper ion, a known mediator of oxidative DNA damage. Simulated MP metabolism using dermal tissues after light irradiation produced these two photoproducts, which reacted with a microsomal fraction (S9) of the skin. A metabolite from MP-3OH, not PHBA, caused distinct DNA damage in the in vitro assay. This active metabolite was identified as protocatechuic acid, a hydrolyzed MP-3OH product. In addition, NADH, a cellular reductant, enhanced DNA damage by approximately five times. These results suggest that reactive oxygen species generated by the redox cycle via metal ion and catechol autoxidation are participating in oxidative DNA damage. This study reveals that MP might cause skin damage involving carcinogenesis through the combined activation of sunlight irradiation and skin esterases. ~~~~~~~~~~~~~~~~~~~~~~
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I will be on the lookout for new findings and research related to this topic and shall keep you posted.
Another advantage for the Sense product line: chemical preservative-free AND paraben-free ~ truly is better for the health of the skin. I sincerely hope you enjoy this weekly newsletter as much as I enjoy writing it for you. And thank you for your positive comments and skin-related questions!
Warmest regards,
Marie Bertrand
SkinScience Clinic www.skinscience.md
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