Zinc, para pantallas solares caseras

http://www.hardlotion.com/blog/2012/6/28/can-we-trust-zinc-oxide.html

Can We Trust Zinc Oxide?

Thursday, June 28, 2012 at 5:55PM

Whether it’s rash cream, sunscreen, itch relief salve or wound care, there’s a common ingredient listed in a variety of skin care products: zinc oxide.  If zinc oxide can truly be counted on to prevent or treat a wide range of skin conditions, the next question is, is it safe?
 After reading up on what the experts say, I continue to bank my confidence on this mineral and here’s why:

1. Chemical sunscreen ingredients like oxybenzone (in 60% of sunscreen products) penetrate the skin and enter the bloodstream, potentially disrupting the hormonal system. Physical or mineral sunscreen ingredients, like zinc oxide and titanium dioxide, reflect the sun like a mirror, and keep the sun’s rays from reaching your skin.  Unlike oxybenzone, zinc oxide is non-toxic.
2. Authorities like Dr. Mercola, the Environmental Working Group, and Dr. Sears recommend using a sunscreen with zinc oxide as the primary sunscreen ingredient. It is the broadest spectrum UVA and UVB reflector that is approved for use as sunscreen by the FDA, and has a time-tested safety record.
3. We’ve used our homemade rash cream and sunscreen on our own family and we’ve found that diaper rash disappears, chaffed skin from rubbing heals quickly, and sunburns are avoided. 

So what’s the deal with the nanoparticle controversy and is zinc oxide linked to cancer?
            A nanometer refers to size, and one nanometer is 100,000 times thinner than a strand of hair. There was concern that particles less than 30 nanometers could be absorbed through the skin and into the bloodstream. Cosmetic companies preferred the smaller particle-sized zinc oxide because the finished product could be applied without excessive whiteness to the skin. It turns out, there are no studies proving that nanoparticles of zinc oxide could penetrate healthy human skin, and studies linking zinc oxide to cancer have been inconclusive. To calm customer fear, the majority of companies who use zinc oxide now use the larger, non-nano sized particles. If you are making your own skin care products and want to be on the safe side, make sure the zinc oxide you buy is non-nano zinc oxide.  (You can order uncoated, non-nano zinc oxide from us at MadeOn or in larger quantities at From Nature With Love.)
Is there any way that zinc oxide is NOT safe?

•    It’s not safe to inhale.
•    It may not be safe to consume.
•    By itself it is not an allergen, but combined with other ingredients, you could react to something in the product. It could be irritating if rubbed into the eye.
•    For best results, use sunscreen containing zinc oxide within a year as zinc oxide has a one year shelf life (unless otherwise noted on your purchased sunscreen).
•   Too much of a sunscreen protection and you’ll keep out the needed UVB light needed to produce vitamin D.  You need to spend some time out in the sun with NO sunscreen.

Have you considered making your own sunscreen? It's easy! 

Resources:
http://breakingnews.ewg.org/2012sunscreen/sunscreens-exposed/sunscreens-exposed-9-surprising-truths/
http://www.badgerbalm.com/s-33-zinc-oxide-and-nanoparticles.aspx