It is rare to find a sunscreen that meets all concerns for safety
Sunscreens work by altering how the skin responds to ultraviolet (UV) radiation. Sunscreen ingredients absorb, reflect or scatter UV rays. For years, manufacturers created sunscreens that were only effective at screening out UVB radiation, since this is the type of radiation that was known to cause sunburn and lead to skin cancer. Recently, however, we have learned that UVA radiation is also harmful. While all sunscreens provide UVB protection, not all provide adequate protection from UVA rays. While SPF numbers tell you how much protection you are getting from UVB rays, they tell you nothing about the level of UVA protection you are getting.
Tanning is caused by UVA radiation that triggers the growth of melanin in our skin. Sunburns are predominantly caused by shorter wavelength UVB exposure. In general, if we block UVB radiation and allow UVA we can tan and not burn. However, the problem is that overexposure to UVA light is also damaging to skin; it is associated with immune suppression, skin aging and even cancer. Unlike sunburn, you don't get an immediate signal that you've had too much sun, so the subtle damages add up over the years. Sunscreens need to provide broad spectrum (UVA and UVB) coverage to protect against sunburn and other long-term skin damage.
There are two categories of commercially available sunscreens, physical sunscreens and chemical sunscreens.
Physical sunscreens work by forming an opaque film that reflects or scatters UV light before it can penetrate the skin. These sunscreens contain mineral ingredients such as zinc oxide and titanium dioxide, which protect against both UVA and UVB rays. These products are the safest and most effective sunscreens available in this country.
Chemical sunscreens work differently. They absorb UV rays before they can cause any damage. They contain one or more ingredients such as avobenzone or oxybenzone, which absorb UVA or UVB rays. Most offer only moderate or weak UVA protection. Many chemical sunscreen ingredients have the potential to cause harm. Vitamin A is a common sunscreen ingredient, listed as an antioxidant that can fight skin aging. However, according to animal studies, sunscreens that contain vitamin A may actually promote the progression of skin cancer. Chemical sunscreens are absorbed into the blood following application to the skin, and it is not yet known whether this causes adverse health effects. Chemical sunscreen ingredients, such as oxybenzone and OMC, are also endocrine disruptors — chemicals that have the ability to mimic, inhibit, or alter the action of the body's natural hormones. Exposure to endocrine disruptors, for example BPA and DDT, have been linked to early puberty in children and hormonal cancers in adults. Endocrine disrupting effects of chemical sunscreens have been reported in animals, and they are likely to affect human health as well. In addition, a number of studies have linked allergic reactions to chemical sunscreens, particularly oxybenzone.
After reviewing sunscreen options, I recommend and make available Kabana's Green Screen Organic sunscreen. It offers balanced UV protection without potentially hazardous chemicals. Green Screen is a physical sunscreen made from all natural and edible grade organic ingredients. This product has received the Environmental Working Group's best rating for safety and effectiveness. http://breakingnews.ewg.org/2011sunscreen/best-sunscreens/best-beach-sport-sunscreens
Of all the physical sunscreen products that receive the highest Evironmental Working Group rating, Kabana Green Screen is one of the very few that does not contain nano or micro sized particles. Many companies choose to use nanoparticles because they are more transparent when applied to the skin. Nanoparticles are defined as particles having at least one dimension smaller than 100 nanometers. Concerns for toxic effects increase as particle size decreases due to the potential for these small particles to absorb through the skin and bypass our body's natural defense mechanisms. The sunscreen industry has chosen to integrate nanoparticle zinc oxide into nearly all mineral sunscreen products, despite a lack of research in regard to particle size safety. Nanosize zinc or titanium penetration through fragile or damaged skin is of particular concern.
There are no labeling requirements for nanoparticle use so consumers have few options for avoiding products containing them. Some manufacturers claim their products are "non-nano" even though a substantial amount of particles are under 100 nanometers and in the nanoscale range. The common label terms "micronized" and "ultra-fine" do not preclude the presence of nano zinc or titanium in sunscreen. Products that claim to be transparent are very likely to contain nanoparticles. The most reliable criteria for choosing a non-nano product is the color left on the skin as larger particles are visible and will leave a faint white color or flesh color if the sunscreen is tinted.
Kabana's Green Screen Sunscreen is available in regular and tinted versions. The tinted product contains the same superior organic and natural ingredients but it's also tinted to a warm beige with iron oxide and is designed to blend in naturally.
Green Screen is also safe for use on children and babies younger than 6 months. The American Academy of Dermatology estimates that 80% of our lifetime skin damage occurs before the age of 18 so it is critical to protect kids from the sun. Children, however, are especially vulnerable to chemical exposure because their young skin is thinner than adult skin and therefore more permeable to the chemicals frequently found in sunscreens. Zinc oxide is the only sunscreen active ingredient that is approved for use on children less than 6 months of age. This product is also environmentally friendly and safe for marine ecosystems and coral reefs.
1. Environmental Working Group. http://breakingnews.ewg.org/2011sunscreen/sunscreens-exposed/the-problem-with-vitamin-a/
2. Janjua NR, Kongshoj B, Andersson AM, Wulf HC. Sunscreens in human plasma and urine after repeated whole-body topical application. J Eur Acad Dermatol Venereol. 2008 Apr;22(4):456-61.
Hayben H, Cameron, M. Roberts H, et al. "Systemic Absorption of Sunscreen after Topical Application." The Lancet 1997;350:9081.
Gustavsson G, Farbrot A, Larko O. "Percutaneous Absorption of Benzophenone-3, a Common Component of Topical Sunscreens." ClinExp Dermatol 2002;27(8):691-4.
3. Cohn BA, Cirillo PM, Christianson RE: Prenatal DDT exposure and testicular cancer: a nested case-control study. Arch Environ Occup Health 2010;65:127-134.
Cohn BA, Wolff MS, Cirillo PM, et al: DDT and breast cancer in young women: new data on the significance of age at exposure. Environ Health Perspect 2007;115:1406-1414.
Maffini MV, Rubin BS, Sonnenschein C, et al: Endocrine disruptors and reproductive health: the case of bisphenol-A. Mol Cell Endocrinol 2006;254-255:179-186.
Roy JR, Chakraborty S, Chakraborty TR: Estrogen-like endocrine disrupting chemicals affecting puberty in humans--a review. Med Sci Monit 2009;15:RA137-145.
4. Schlumpf M, Schmid P, Durrer S, et al. Endocrine activity and developmental toxicity of cosmetic UV filters--an update. Toxicology. 2004 Dec 1;205(1-2):113-22.
Schlumpf M, Cotton B, Conscience M, et al. In vitro and in vivo estrogenicity of UV screens. Environ Health Perspect. 2001 Mar;109(3):239-44.
5. Szczurko C, Dompmartin, Michel M, et al. "Photocontact Allergy to Oxybenzone: 10 years of Experience." Photodermatol PhotoimmunolPhotomed 1994;10(4):144-7.
Schauder S, Ippen H. "Contact and Photocontact Sensitivity to Sunscreens: Review of a 15-year Experience and of the Literature." Contact Dermatitis 1997;37(5):221-32.