THERE IS NO REASON TO NOT USE A MINERAL SUNSCREEN
Some new mineral sunscreens apply clear. 25% zinc oxide (The Sunscreen Company) applies clear in 3 sec on dark or black (Type 5 & 6) skin.
My previous blog post described why aromatic organic UV filters – all with a benzene ring and belonging to the petrochemical class of chemicals – are neither SAFE or EFFECTIVE. A recent article on CNET quoted a dermatologist on the comparison between mineral sunscreens and those using 12 aromatic organic UV filters delisted by the US FDA. It was full of dated and inaccurate information. One astute reader commented that “this article is written mainly to support chemical sunscreens when there is almost no reason not to use physical”. She was exactly right!! I would add that there is every reason NOT TO EVER USE organic petrochemical UV filters – wrongly called a chemical sunscreen. All UV filters are CHEMICALS - fundamental Chemistry. Some sunscreens are organic -meaning carbon based with complex carbon chains and phenolic or benzene rings in their structure. Mineral UV filters are inorganic compounds (contain no carbon atoms) like zinc oxide, titanium dioxide, iron oxide, and others. Their individual atoms all occur on the Table of Chemical Elements. Mineral or inorganic UV filters belong to the class of INSOLUBLE CHEMICALS with a large molecular weight > 500 Daltons, which prevents absorption and bioavailability. Organicaromatic petrochemical UV filters in the FDA category III (oxybenzone, avobenzone, homosalate, and 9 others), belong to the class of SOLUBLE UV filters with a small molecular weight < 500 Daltons, the threshold for absorption. All permeate human skin and become bioavailable to every cell in your body, even to the human fetus.
Both the article and that comment suggested that mineral sunscreens were not as aesthetic as petrochemical oily filters. The comment also raised the issue of toxicity to the marine environment. Both require accurate information. Fifteen to 20,000 tons of SOLUBLE organic UV filters in popular sunscreens wash off annually and destroy our reefs, similar to an oil spill – an episodic local event, while sunscreen slicks are daily and worldwide, and can damage reefs 6-10 miles offshore. Organic soluble UV filters pollute every link in the land-based aquifer leading to the oceans. Almost all of the 12 organic filters delisted by the US FDA are found in Waste Water Treatment Plant (WWTP) influents and effluents, since they do not remove these petrochemicals. By 2015, thirty-three scientific publications confirmed their contamination of WWTP inflow and outflow, swimming pools, tap-water, urban groundwater, freshwater (rivers and lakes), estuaries, seawater, and of sediments from rivers, lakes, beach sand, soils, and sludge.
Regional pollution of open water around coral reefs was confirmed for oxybenzone in the U.S. Virgin Islands, homosalate and oxybenzone in Japanese waters, and for oxybenzone and avobenzone in South Carolina waters. It is a lengthy exercise to reference the widespread pollution of global water. Studies document the presence of the FDA category III filters in rivers – even in the remote Swiss Alps and Australian estuaries, lakes, streams, ponds and wastewater, wherever humans use sunscreens and personal care products. Even where sunscreen use must be low – the Arctic – these filters pollute, likely from loop currents that bring them from distant coastal waters and cruise ship discharge in the Northern Atlantic. The ubiquitous contamination by these petrochemical UV filters of the entire global environment is confirmed by their presence in the open waters of the Pacific Ocean, the surface waters of China, Japan, the USA, Thailand, and every global coral reef system.
The presence and resulting toxicity to marine species is extensive. Coral samples exposed to even small concentrations of these compounds exhibited severe stress responses and often mortality. Studies identify these drastic effects in scleractinian corals exposed to relatively low concentrations oxybenzone, which was identified as a skeletal endocrine disruptor in planula of Stylophora pistillata (Downs et al 2015). Studies confirm that soluble organic UV filters bioaccumulate in mussels, corals , crabs, shrimps, prawns, squids fish, dolphins from the coast of Brazil, in-cormorants from Switzerland, and in unhatched eggs of bird species from the Natural Park of Doñana (SW of Spain), confirming biomagnification of these substances. It has been confirmed that these agents have the same effects of hormone disruption in marine species and aquatic biota, as they do in humans. Even dermatologists now admit that mineral sunscreens are safer for the environment (Schneider and Lim 2019) – ”For those concerned about emerging evidence of environmental impact of organic UV filters, based on current evidence, ZnO and TiO ‐containing sunscreens are safe alternatives”.The senior author - Dr. Henry Lim – also stated in a recent interview that he NOW recommends mineral sunscreens for use in pregnancy. I have stringently recommended mineral sunscreens for every consumer over the past 20 years, but the use of soluble organic UV filters delisted by the US FDA must be avoided by expectant or nursing mothers, young and adolescent children, and couples trying to conceive.
Regional bans of soluble organic filters were implemented to protect the reefs in Hawaii, Marshall Islands, Palau, US Virgin Islands, Key west, and the Dutch Antilles. Hawaii has now voted to institute a wider ban to include ALL 12 of the US FDA category III filters. Coral reefs acting as the sentinel organism in the marine ecosystem provide 8 trillion USD of economic benefits to humans.
Another point raised in the article is that mineral sunscreens are less desirable from an aesthetic (“white residue”) or sensory feel on skin (“sticky”). One person makes the comment that issues with mineral sunscreens are “difficulty with rubbing in” and requiring an “ extra 30 seconds rubbing”. Mineral sunscreens are safer for humans and our environment and some are now as aesthetic as soluble sunscreens using petrochemicals, incorrectly called chemical sunscreens.
It was reported last year that Former First Lady, Michele Obama, used a 25% zinc oxide sunscreen, and other celebrities with dark or brown skin have said they use the same sunscreen. Venus Williams just launched as part of her “Eleven” product line, two 25% zinc oxide sunscreens - one a serum, so thin, it is dispensed by a dropper, the other a cream. Both apply clear within a few seconds. Ms. Williams states that both are great for any skin tone, and provide the high UVA protection to prevent skin cancer and photoaging.
© Denis K. Dudley MD, JUNE 2020. All rights reserved.