Bestselling Vitamin D author lends support to ‘Paleo’ Pete Evans on sunscreen dangers
July 15, 2016iwishartNew ZealandComments Off on Bestselling Vitamin D author lends support to ‘Paleo’ Pete Evans on sunscreen dangers
An award-winning investigative journalist and bestselling author has lent his weight to MKR celebrity paleo chef Pete Evans and his warnings about sunscreen use this past week.
Ian Wishart, whose book “Vitamin D: Is This The Miracle Vitamin?” has been an international bestseller, has released two chapters of the book for free today so the public can see for themselves the debate about sunscreen that scientists are having behind closed doors.
“It isn’t pretty,” Wishart said today. “I checked the latest peer-reviewed reports on sunscreens before releasing this today and what I say in these Vitamin D book chapters remains correct – there is not one unambiguous, credible randomised controlled trial that shows sunscreen actually helps prevent melanoma, in fact, many studies are saying sunscreens are giving the public a false sense of security thanks to misleading claims from skin cancer charities sponsored by sunscreen companies.
“Paleo Pete is right. The science is showing many sunscreens could be causing cancer because their chemicals break down in sunlight and cause free radical damages in our bodies, and secondly after thirty years of slip, slop, slap and billions of dollars in sunscreen sales, there’s still no hard evidence that sunscreens are a shield against melanoma.
“It’s an international scandal. Good on Evans for speaking up.”
Ian Wishart’s Vitamin D book is available on Amazon or at Oliver’s stores and selected bookshops across Australia.
His upcoming new book “Show Me The Money, Honey: The Truth About Big Pharma’s War On Salt, Chocolate, Cholesterol & The Natural Health Products That Could Save Your Life” will be released in early August.
The selected chapters on sunscreen being made publicly available for the first time follow here:
Chapter 13
SUNSCREENS:
A CLEAR AND PRESENT DANGER
“Using sunscreen has not been shown to prevent melanoma or basal cell carcinoma”
– American Academy of Pediatricians, 2011
It seems such an easy message to sell: Slip, slop, slap. The idea of using a chemical lotion to block harmful UV rays as a primary method of sun protection has a lot of simple appeal. Clearly, people using sunscreen don’t burn and they can easily spot the convenience and health benefits of that particular outcome. To that extent, sunscreen sells itself as users become reliant on it to help maintain an outdoor lifestyle for themselves and their families. But here’s the rub: there’s strong scientific evidence that sunscreens don’t actually work against the most dangerous skin cancers, and there’s strong emerging evidence that sunscreens may actually contain toxic particles that cause cancer and other genetic damage.
First, however, a little history.
In 1935, your chance of developing melanoma in your lifetime was around 1:1500. Today, melanoma risk has ballooned to 1:33 for a baby born now.[1] Why such a huge rise in risk?
The first commercial sunscreen was invented in 1938 by chemistry student Franz Greiter, who allegedly received a sunburn while climbing Piz Buin in the Swiss Alps that inspired him to develop a protective lotion.
Also from the necessity-is-the-mother-of-invention file, US WWII serviceman Benjamin Green – apparently sick of getting sunburnt while fighting in the Pacific – developed his own sunscreen independently in 1944 based on red petroleum jelly, which later became the stepping stone for Coppertone to develop its range of sunscreens.
You won’t find the ingredients used in those first sunscreens in any products available today. Para-aminobenzoic acid, or PABA, for example, was patented in 1943 and whilst being a good UVB barrier, often used in sunscreens and women’s cosmetics, it has subsequently been found to degrade when exposed to sunlight and may be carcinogenic under certain circumstances[2], which somewhat defeats the purpose. It is banned in Europe, and no longer used in many other regions.
Sunscreens have gone through a multitude of formulations in the attempt for the perfect lotion, but so far no one has cracked it. There are two varieties available to consumers, organic-based lotions or mineral based. The organically-derived sunscreens rely on the following FDA-approved[3] chemical compounds:
Cinoxate
Ensulizole
Homosalate
Octinoxate
Octocrylene
Padimate O
Para-aminobenzoic acid (PABA)
Trolamine
Those compounds just listed are only effective against UVB radiation. They will not block any UVA radiation at all.
There are a further subset of organic molecules that sunscreen manufacturers have found have some limited effect on UVA rays:
Dioxybenzone
Oxybenzone
Sulibenzone
Those chemicals are effective against UVB and UVA-2 radiation frequencies, but not effective against UVA-1 frequencies. L’Oreal has developed a couple of chemicals that are only effective against UVA-2 radiation (again, to a limited extent), but there is only one organic compound approved in the US that is effective in any way against UVA-1 radiation: Avobenzone.[4]
The problem with many of these organic (mostly benzene-based) sunscreen compounds is that they are prone to “photodegradation”, or breaking down when exposed to sunlight.
“Controversy,” reports one recent scientific study, “has also developed regarding the possibility of adverse biological effects from various ingredients in sunscreens. Oxybenzone, an ingredient widely used in sunscreens, is purported to have a potentially disruptive effect on hormonal homeostasis.”
What scientists have found is that Oxybenzone (aka Benzophenone-3) is well and truly absorbed into the human body through the skin, after being applied in sunscreens. It has turned up in the urine and blood of 96.8% of people tested, and is believed to accumulate in vital organs like the kidney, liver, spleen and male testes, but also in the intestines, stomach, heart and adrenal glands. It has been linked in one scientific study to low birth weight in babies.[5]
What does it do? We know it has an estrogen like effect and has been scientifically shown to stimulate human breast cancer cells[6] – not necessarily a good thing if you are at risk of developing breast cancer, as many women are. It also gives men an extra tweak of estrogen and displays – at a biochemical level – what scientists call “anti androgenic” or feminising hormonal effects.
A study of 15 young males and 17 post-menopausal females over two weeks measured statistically significant hormonal changes after using oxybenzone, but not enough to cause what scientists call “clinically significant perturbations”. In other words, while the sunscreen chemical is affecting our bodies, this tiny study of 32 people didn’t detect anything requiring treatment or intervention. What of the effect on babies or children, however? We don’t know. We do know that sunscreen ingredients are now being found in human breast milk.[7]
One scientific study on human wastewater outflows into rivers has found however that all that oxybenzone we are absorbing and excreting is having a horrific effect on marine life, dramatically reducing the fertility of trout and other fish species exposed to oxybenzone.[8]
In the interests of balance, a further analysis has worked out it could take up to 277 years for a woman using sunscreen every day to finally get enough of a build-up of oxybenzone to harm her, pointing out that what is toxic to small animals is not necessarily so to humans.[9]
What we do know, however, is that oxybenzone may become ineffective and even toxic under normal sunscreen use conditions. A just-released study has tested what happens to oxybenzone sunscreens when their users jump into chlorinated swimming pools or spas. The chlorine reacted with the oxybenzone and “caused significantly more cell death than unchlorinated controls…Exposing a commercially available sunscreen product to chlorine also resulted in decreased UV absorbance, loss of UV protection, and enhanced cytotoxicity [meaning it becomes poisonous to human cells].”[10]
There are question marks about the safety of other ingredients in organic sunscreens.
“Retinyl palmitate, a compound used extensively in various cosmetic and personal care products, has received wide attention as a potential photocarcinogen (light-activated carcinogen).”
This chemical has been shown to have carcinogenic properties in animal testing, and it also has been shown to create harmful free radicals[11] in the skin as a result of breaking down under UV exposure. Scientific reaction is mixed however, with some suggesting that other antioxidant compounds in the human skin should be capable of protecting against damage caused by retinyl palmitate generated free radicals,[12] and they also argue that the mice in the cancer tests were prone to skin cancer anyway.
Like oxybenzone, in the absence of seriously hard evidence showing the compound is definitely harmful, retinyl palmitate will remain in sunscreens used by adults and children.
In 2005 a series of experiments using sunscreen containing octocrylene, octylmethoxycinnamate and benzophenone-3 revealed that within one hour of application according to manufacturer’s instructions, the chemicals were generating more “reactive oxygen species”(ROS) in the skin than people wearing no sunscreen were getting via direct UV radiation. In other words, the sunscreen was acting like oil in a frypan in terms of its effect on users’ skin and resultant ROS damage.[13] It’s one of the reasons health authorities now seek regular re-application of yet more chemicals every hour or so, locking sunscreen users into a vicious circle.
The second category of sun screens, the mineral-based ones, have issues of their own. These are the Zinc Oxide and Titanium Dioxide sun blocks. Unlike the organics, the Zinc and Titanium formulations were not thought to break down in sunlight and cause damage on the skin, meaning they stay protective for longer. However, in the race to become more effective these sunscreens deliver their active ingredients as nanoparticles – molecular compounds so small they can potentially pass through barriers like the human skin. Researchers have shown that when Titanium dioxide is stimulated by UV rays, its electrons become more energised and can “react with nearby oxygen and hydrogen compounds to produce highly reactive free radical compounds…when in contact with our skin these radicals can oxidise and reduce compounds including DNA, resulting in significant mutagenesis [causes mutations at a cellular level].”[14] Additionally, the resulting free radicals can react with organic sunscreen ingredients to create acids.
All of this is happening on and possibly under your skin unseen, of course, whilst you and your children happily sunbathe or play on the beach.
More than one research team has pointed out that the race to nanotechnology in sunscreens and cosmetics has been done “with no regard to the potential health risks.”[15]
“Much concern has been voiced that the integration of nano-material technology into everyday formulations has outpaced the body of research evaluating their safety,” echo Burnett & Wang, who nonetheless reach the conclusion that sunscreens should still be used regardless.[16]
Sadly, health agencies in Europe, Japan, Australia and New Zealand have been so keen to promote sunscreens that they have allowed products to go to market untested in regard to whether their ingredients may in fact cause cancer in their own right. Even in the US most ingredients have not been required to pass official safety tests.
Scientists now know that Zinc Oxide does in fact break down under UVB light, shedding zinc (Zn2+). One study found “a reduction in cell viability” as a result and that Zinc oxide breakdown “causes cytotoxicity and oxidative stress [the generation of free radicals].”[17]
Another recent study paints an even more disturbing picture – actual genetic damage resulting from nanotechnology in sunscreens and makeup. Remember, it is DNA damage that leads to skin cancer and melanoma, so this is where speculation about sunscreens possibly causing skin cancer is focused.
“Due to the extremely small size of the nanoparticles (NPs) being used, there is a concern that they may interact directly with macromolecules such as DNA,” notes the study, published in the journal Toxicology Letters.[18]
“The present study was aimed to assess the genotoxicity of zincoxide (ZnO) NPs, one of the widely used ingredients of cosmetics, and other dermatological preparations in human epidermal cell line (A431). A reduction in cell viability as a function of both NP concentration as well as exposure time was observed.”
The findings warn that Zinc oxide nanoparticles, “even at low concentrations, possess a genotoxic potential” capable of genetically mutating or harming human skin. “Hence, caution should be taken in their use in dermatological preparations as well as while handling.”
This again raises valid questions about whether sunscreens are safe to use on infants and children, let alone adults.
“Although toxicity in infants or young children resulting from sunscreen absorption has not been reported,” writes Dr Sophie Balk, “skin permeability to topically applied products is of concern in the very young, especially in preterm infants. Absorptive and other properties of children’s skin may differ from those of adult skin until children are at least 2 years old.”[19]
Thomas Faunce, a biomedicine legal expert based at Australian National University in Canberra, says authorities may need to step up.
“It may be time for Australian safety regulators to apply the precautionary principle in this contact and increase labelling requirements about the use of nanoparticles in sunscreens.”[20]
The problem is, how do you tackle the problem when health authorities, manufacturers and cancer charities are all financially in bed with each other?
Australia and New Zealand’s cancer societies, for example, earn millions of dollars a year marketing their own range of sunscreen products. One of those, like similar products in the US and elsewhere, is a combination SPF30+ sunscreen and insect repellent. It contains the insecticide “Deet”, known to science as diethyl toluamide, and the sunscreen octyl-methoxycinnamate. Ignore the fact that these two chemicals or their derivatives, when mixed together, can be potentially harmful.[21] Instead, note that the combo also lists an ingredient called piperonyl butoxide,[22] otherwise known as PBO, which is often added to “natural” insect sprays.
A 2011 study – the first of its kind – found this supposedly environmentally friendly chemical PBO appears to be as toxic to infants and children as letting them lick lead paint. The study found a four point drop in mental development levels for children whose homes are exposed to piperonyl butoxide in insect spray dispensers.[23]
Whilst that particular study was looking at the toxicity of PBO inhaled from automatic household spray dispensers, the application of the product directly on the skin in a sunscreen could also possibly leach it into the bloodstream, particularly of pregnant women or children. You are also likely to find PBO in headlice treatments for children.
“Children who were more highly exposed to PBO in personal air samples (≥4.34 ng/m3) scored 3.9 points lower on the Mental Developmental Index than those with lower exposures.[24]
“This drop in IQ points is similar to that observed in response to lead exposure,” lead researcher Megan Horton of Columbia’s Mailman School of Public Health told journalists. “While perhaps not impacting an individual’s overall function, it is educationally meaningful and could shift the distribution of children in the society who would be in need of early intervention services”.[25]
You might be surprised to discover that – despite being approved for use in households and on children – no significant human safety testing of PBO has ever taken place until the 2011 study.[26] And that’s kind of the main point here – pesticide and sunscreen manufacturers have been given free rein to use the public as guinea pigs.
The New Zealand Cancer Society helpfully publishes a “materials safety sheet” on the ingredients of its products. The poisons information in the sheet states the combined sunscreen and insect repellent is “not suitable for babies and toddlers”. Great advice, and it was delivered to the Cancer Society in October 2009,[27] but it does not appear anywhere as a warning on the tube of sunscreen on sale in 2012. Thousands of families are likely to have used this harmful product on and around their children. Indeed, the tube labelling in NZ states “use this sunscreen in conjunction with other sunsmart behaviour”, including “keep infants in the shade”, clearly implying to me that it is safe for children as part of a mix of precautions.
The Cancer Council of Australia’s PBO-containing product describes itself as “Ideal for families and childcare centers” in a description for the 500ml pump-bottle version.[28]
The Cancer Council defends its use of nanoparticles on its website:[29]
“Nanotechnology has been used in sunscreens for many years. To date, our assessment, drawing on the best available evidence, is that nanoparticulates used in sunscreens do not pose a risk. However, we continue to monitor research and welcome any new research that sheds more light on this topic.
“Sunscreen formulas and their components are regulated through the Therapeutic Goods Administration (TGA). In early 2009, the TGA conducted an updated review of the scientific literature in relation to the use of nanoparticulate zinc oxide and titanium dioxide in sunscreens.
“The TGA review concluded that:
The potential for titanium dioxide and zinc oxide nanoparticles in sunscreens to cause adverse effects depends primarily upon the ability of the nanoparticles to reach viable skin cells; and
To date, the current weight of evidence suggests that titanium dioxide and zinc oxide nanoparticles do not reach viable skin cells; rather, they remain on the surface of the skin and in the outer layer of the skin that is composed of non-viable cells.”
That review was conducted in early 2009. Evidently nothing further has been done by Australasian authorities. Yet in late 2009 this study was released:[30]
Titanium dioxide (TiO2) nanoparticles, found in everything from cosmetics to sunscreen to paint to vitamins, caused systemic genetic damage in mice, according to a comprehensive study conducted by researchers at UCLA’s Jonsson Comprehensive Cancer Center.
“The TiO2 nanoparticles induced single- and double-strand DNA breaks and also caused chromosomal damage as well as inflammation, all of which increase the risk for cancer. The UCLA study is the first to show that the nanoparticles had such an effect, said Robert Schiestl, a professor of pathology, radiation oncology and environmental health sciences, a Jonsson Cancer Center scientist and the study’s senior author.
Once in the system, the TiO2 nanoparticles accumulate in different organs because the body has no way to eliminate them. And because they are so small, they can go everywhere in the body, even through cells, and may interfere with sub-cellular mechanisms.
The study appeared the week of November 16 in the journal Cancer Research.
In the past, these TiO2 nanoparticles have been considered non-toxic in that they do not incite a chemical reaction. Instead, it is surface interactions that the nanoparticles have within their environment- in this case inside a mouse–that is causing the genetic damage, Schiestl said. They wander throughout the body causing oxidative stress, which can lead to cell death.
It is a novel mechanism of toxicity, a physicochemical reaction, these particles cause in comparison to regular chemical toxins, which are the usual subjects of toxicological research, Schiestl said.
“The novel principle is that titanium by itself is chemically inert. However, when the particles become progressively smaller, their surface, in turn, becomes progressively bigger and in the interaction of this surface with the environment oxidative stress is induced,” he said. “This is the first comprehensive study of titanium dioxide nanoparticle-induced genotoxicity, possibly caused by a secondary mechanism associated with inflammation and/or oxidative stress. Given the growing use of these nanoparticles, these findings raise concern about potential health hazards associated with exposure.”
How do we reconcile studies like that with marketing campaigns telling parents to use titanium dioxide sunscreens on their children? It is true that studies so far have not found penetration of zinc or titanium through the skin barrier beyond 17 layers, but those tests have been done on adult skin, not infant skin, which is much less developed. Additionally, young children and particularly babies may suck skin with sunblock on, therefore ingesting the chemicals. Given that titanium dioxide nanoparticles are also used as a whitener in toothpaste, perhaps there’s a different avenue for concern, although that’s another story!
What it all comes back to, in the end, is that warning that nanotechnology usage has exploded into the community long before safety has been definitively proven. If sunscreens were a dead cert, 100% effective barrier to melanoma and all other skin cancers, you might look at the odds and say it’s worth using them. Sunscreens don’t prevent most skin cancers, however, and on current evidence might (either directly or indirectly) cause rather than prevent melanoma, so the risk/benefit ratio might be harder for parents to assess.
That’s not the only concern, however.
Virtually every one of the NZ Cancer Society sunscreens (and a number of the Australian ones) also contains Vitamin E as an antioxidant, but there are no warnings on the packs[31] about the possible dangers of Vitamin E to men at risk of prostate cancer. A recent study found men using Vitamin E suffered a significant 17% increase in risk of developing prostate cancer, meaning you would not want to be using it daily in a sunscreen as recommended by health authorities. As the study warns: “Dietary supplementation with vitamin E significantly increased the risk of prostate cancer among healthy men.”[32]
Prostate cancer rates have – like melanoma – gone through the roof in the past three decades. Are sunscreens partly to blame? The Journal of Cosmetic Dermatology has previously reported that Vitamin E is absorbed into the human body at a level eleven times greater when applied to the skin, as compared to taking it in dietary supplement form.[33]
This is not to pick on the Australia or New Zealand cancer societies, by the way. The formulations in their products are similar to those used by other commercial suppliers. Don’t assume that just because a product is marketed by reputable companies or charities, advertised on TV and sold in supermarkets that it is actually 100% risk-free. Do your homework.
Then there’s the strange case of gardeners and agriculturalists, many of whom use herbicides or pesticides of some kind as part of their work. A 2004 study revealed sunscreens act like an open door for poisonous chemicals to penetrate your skin. The herbicide in question was 2,4-D – which forms one half of the deadly “Agent Orange” formula. There was a 60% increase in the amount of herbicide that penetrated the skin via sunscreen, compared with no sunscreen, resulting in what researchers called “penetration enhancement” that showed “physical damage” to the skin.[34]
As you can see then, there are nagging concerns about whether sunscreens might actually be toxic, and whether they open gateways for other toxins. What comes next, however, is a bigger problem for the sunscreen industry: do they actually work? What you are about to read may astound you.
Chapter 14
MELANOMA: COULD SUNSCREENS
BE CAUSING IT?
“The factor most significantly associated with increased melanoma risk was the use of sunscreens. Subjects who often used sunscreens had an increased odds ratio of 3.47 (three and a half times more risk) compared with subjects who never used sunscreens”
– Journal of Melanoma Research, 1998
The best explanation for why melanoma rates have skyrocketed since 1935 may be a relatively simple one: there’s no hard evidence that sunscreens protect you against melanoma.
Think about that for a moment, let it sink in.
Numerous scientific studies have failed to find evidence that sunscreens are effective against the risk of developing the deadliest skin cancer, melanoma. In fact, in some cases, they have found sunscreen users have a significantly higher risk of developing melanoma.
A telltale sign of growing risk are what are called “nevi” – the brownish skin lesions like moles or dark freckles that can often morph into melanoma. A Canadian study of school children using SPF-30 broad spectrum sunscreen in randomised, controlled conditions over a three year period found regular sunscreen users did have “a slight decrease” in the number of new nevi on their skin, “however, this effect was seen only in children with freckles”. In other words, for everyone else, sunscreen use failed to prevent the development of melanoma precursors.[35]
“In a large European study of white school-age children,” report Jou et al in their June 2012 study, “sunscreen use was associated with an increased number of nevi.”
In 2000, the International Journal of Cancer reported similar findings after a study involving nearly 1,500 people in Sweden.
“Persons who used sunscreens did not have a decreased risk of malignant melanoma. Instead, a significantly elevated odds-ratio (nearly double) for developing malignant melanoma after regular sunscreen use was found.”[36]
Even more disturbing for readers, the massive increase in melanoma risk for sunscreen users took place even though participants “did not suffer from sunburns while using sunscreens”.
The only good news from scientific studies of sunscreen effectiveness is that the lotions are effective at helping prevent one of the main skin cancers, known as squamous cell carcinomas. These are very slow-growing cancers which, whilst they can spread, usually don’t before they are diagnosed. Sunscreens don’t protect you from the most common skin cancer – basal cell carcinoma – or the most deadly, melanoma. Sunscreens should carry warning labels to this effect, like cigarette packets, but they don’t.
This refusal by manufacturers and health authorities to spell out the ineffectiveness is all the more inexplicable when you consider that every summer it is the sad and tragic stories of youthful melanoma victims that are trotted out to the news media and the public as the figureheads of sun safety messages urging people to buy and use sunscreen.
These latest studies have prompted the American Academy of Pediatricians to announce recently: “Correctly using sunscreen can prevent sunburn and is believed to protect against SCC. Using sunscreen has not, however, been shown to prevent melanoma or basal cell carcinoma.”[37]
Remember, it is primarily melanoma that kills. The sunscreen in your cupboard is not lowering your risk of dying from skin cancer, no matter how many times a smiling person on TV urges you to slop on the sunscreen because of the dangers of melanoma. At best, the protective effects of sunscreen appear to be largely cosmetic in terms of slowing down solar aging. But at worst, sunscreens may be dangerously lulling you into complacency. Could it be that our massive melanoma rates are largely the result of a worldwide public health campaign encouraging people to use sunscreens that turn out to have been ineffective against melanoma?
Even the effectiveness against SCC cancers is far from total. A reduction of only 40% amongst people who use sunscreen religiously and well, still leaves a substantial relative risk of developing it.
It’s not the first time a major public health awareness campaign has been launched on the back of erroneous data and backfired tragically. Another live example that many readers will be familiar with is the global promotion of condoms in “safe sex” campaigns. Medical studies actually show condoms are next to useless against many sexually transmitted infections, with the result that sexual infection statistics have risen rapidly amongst teenagers who’ve been lulled into a false sense of security because of desires by health authorities to present simple, dumbed-down safe sex messages.[38]
In the case of melanoma, the embarrassment for public health officials actually gets even worse. Studies are showing that – ironically – people who get the most exposure to the sun are more likely to survive melanoma if they develop it, than people who slip, slop, slap religiously.
Let that one sink in for a moment as well.
If you regularly sunbathe and build up a tan and vitamin D reserves, your chances of surviving melanoma are much higher than if you are a 50 year old wallflower with the skin of a 20 year old who has sheltered away from the sun all her life. Researchers at the University of Leeds discovered this in a major study published in conjunction with the US National Institutes of Health in September 2009. People who regularly sunbathed and got melanoma were found 30% more likely to survive than non-sunbathers.[39]
Part of the reason for this enigma appears to be, yet again, the protective effect of vitamin D. Melanoma patients found to have the highest levels of vitamin D in their blood turned out to have the thinnest melanoma lesions on their skin – and the shallower the melanoma the less risk there is of it spreading deeper and further into the body.
“Higher [vitamin D3] levels, at diagnosis, are associated with both thinner tumours and better survival from melanoma,” reported the Leeds study. “Patients with melanoma, and those at high risk of melanoma, should seek to ensure vitamin D sufficiency.”
This also explains one of the mysteries to arise from Australia and New Zealand. At this current time in planetary history, the southern hemisphere is – because of Earth’s tilt angle – closer to the sun during summer than the northern hemisphere is during the northern summer. That means the southern nations are getting a stronger dose of UV radiation each year than Americans or Europeans.[40] It’s one of the reasons that the antipodes share the highest rates of melanoma in the world. Yet here’s the strange thing: they don’t have the highest death rates from melanoma. Far from it.
This apparent contradiction was one of the first clues that led researchers to suspect vitamin D had a protective role against dying from cancer. How else could one explain the highest rates of melanoma in the world yet also the best survival rates?
For inquisitive scientists like Leeds University’s Julia A. Newton-Bishop – the lead author on the original study, these paradoxes opened up fresh grounds for investigation. If sunbathers were more likely to survive melanoma, could it possibly be that sunbathing might actually help prevent melanoma from developing in the first place?
The idea seems ludicrous – we all know that sunbathing causes melanoma, don’t we? The reality is, we know less about the complex causes of melanoma than the simple messages published via the news media each summer imply.
Newton-Bishop’s team continued to dig deeper for answers and, in late 2010, they made a bombshell discovery: British residents who sunbathed for five hours or more without sunscreen per day each weekend during summer reduced their risk of developing melanoma by an incredible 33%, compared with people who stayed out of the sun.
That’s another of those let-it-sink-in moments.
If you look at it another way, people who obeyed the ‘sun smart’ message, slopped on the sunscreen and stayed out of the light, were a staggering 50% more likely to develop melanoma than people who actively sunbathed without sunscreen. This too might explain why so many melanoma victims in the media say, “but I only sunbathed occasionally, and I always tried to use sunscreen, it only took one time…”.
“When the data were analysed for tumours in different body sites,” reported the European Journal of Cancer study, “the protective effect of increased weekend sun exposure was strongest for limb tumours and tumours on rare body sites [those melanomas that frequently pop up where the sun don’t shine].”
Sun-shy people had more than double the risk of developing head and neck melanomas than their tanned, beach-going compatriots.[41]
Which brings us back to the issue raised at the start of this chapter: why are those people who religiously use sunscreen the most likely to develop the deadliest skin cancer? The answer appears to lie in a battle between Nature and Big Pharma.
If you adhere to the ‘nature’ argument, humans have been living naturally under the sun for tens of thousands of years. Indeed, all life on earth is dependent on solar radiation and our bodies are highly attuned to deal with it. Why then, are we dealing with a sudden explosion in the number of skin cancer cases?
In humankind’s quest to tame Nature, and indeed to advance ourselves, we have moved from a simple agricultural outdoors lifestyle to a mostly indoors one, particularly within the past 100 years. We no longer spend long hours each day outside in the sun, developing protective suntans that last year-round. Instead, we creep from house to car to office to car to house, five days a week, barely getting a few minutes of genuine sun a day, if that.
As a result of our indoor lives, we find we now need protection from the sun because we don’t have the time to build up tans gradually and naturally in the daylight in time for the summer break, we are simply too busy. So we reach for a pharmaceutical solution, trusting that the chemists have got it right and that human intelligence has beaten Nature.
This scenario would be all well and good – if sunscreens worked. The truth is, however, they have a lot of limitations. If your chances of getting melanoma were one in 1500 in 1935 (before the invention of sunscreens), and as high as one in 33 now, something has clearly gone wrong with the Big Picture.[42] In losing the protective effect of a long-lasting suntan, we have placed our trust in imperfect chemical formulations.
And here’s where it went wrong. For decades, sunscreens were quite good at blocking UVB radiation, but utterly useless at blocking UVA radiation, which actually makes up nearly 95% of the total UV light reaching the surface of the earth. UVA penetrates glass (and sunglasses, incidentally), which UVB doesn’t, and it penetrates more deeply into the human skin and so “may have greater destructive potential”. It’s known that UVA is more likely to age your skin and cause wrinkles. It is UVA that fades your carpets. UVB, on the other hand, is primarily responsible for causing sunburn but will also cause photo-aging of your skin.
However, here’s the important part. It is UVB that primarily stimulates your body to produce more melanin, the darker protective pigmentation we call a suntan. UVA radiation will also create an instant same day tan, but it uses existing melanin in the skin to achieve this and thus doesn’t actually stimulate a protective tanning response because it does not generate new melanin. This is one of the criticisms of sunbeds, which are mostly UVA driven – they’re very good at creating a rapid tan, but the tan is not a protective one. You cannot take a sunbed tan out into the great wide open and assume you are protected.
So here’s the twist. Sunscreens that blocked UVB actually prevented your body from defending itself from total solar radiation. Many of the melanomas appearing in Baby Boomers and Gen-X today are arguably a direct result of dodgy sunscreen products from the sixties onwards that gave people a false sense of security. They were doing more damage to themselves by lying in the sun all day with a UVB sunblock on, mistakenly believing that because they were not burning then they were safe. In the meantime, UVA radiation poured into them utterly unmolested.
“UVA may have a greater potential for carcinogenesis”, reports the Cleveland Clinic Journal of Medicine.[43]
If this was an episode of Star Trek, a UVB sunblock while sunbathing (thus fooling the body into not generating a protective tan) is the equivalent of leaving the Enterprise “shields down” and unarmed while the enemy UVA sneaks aboard.
That, then, was strategic error number one. “A common misperception is that sunscreens decrease the risk of burning and allow people to increase their exposure to UV radiation. This results in increased exposure to UVA and thus increases the risk of skin cancers and facilitates photo-aging.”[44]
Hands up everyone who has languished on the beach for hours, thinking that their sunscreen is protecting them.
For that reason, the industry has moved predominantly to “broad spectrum” sunscreens that claim to block both UVB and UVA rays. For those who regularly apply broad spectrum SPF-16 or higher every day, studies have shown a long term 38% reduction in the incidence of squamous cell carcinoma – one of the least harmful kinds of skin cancer.[45]
Sadly, that might be all that sunscreens do.
“Although sunscreens appear to be effective in preventing actinic keratosis [sun spots on the skin] and squamous cell carcinoma, the evidence that they also prevent basal cell carcinoma and melanoma has been inconclusive,” reported researcher Paul Jou in June 2012.
Melanoma is the real killer when it comes to skin cancer. The mortality rate from melanoma is as high as one in five (20%). In contrast, the mortality rates from basal cell carcinoma (the most common skin cancer) and squamous cell carcinoma are around 1 in 333 (a 0.3% mortality rate). Melanoma is responsible for 75% of all skin cancer deaths. To discover that the primary weapon in the fight for a summer lifestyle is largely useless against the most common and deadliest skin cancers is disconcerting, to say the least.
“Safety of sunscreens is a concern,” reports study author Dr Marianne Berwick, of the University of New Mexico’s Cancer Centre and Department of Internal Medicine. “Sunscreen companies have emotionally and inaccurately promoted the use of sunscreens.”
With global sunscreen sales in the multi-billions of dollars every year, there’s money to be made in selling products that can be linked to public health campaigns. The problem for consumers and regulators is whether in fact sunscreens are worth what we are paying for them, or whether consumer fears have been overhyped.
More disturbing in my view, however, is that sunsmart promotions are not passing on this inconvenient truth to the public. New Zealand’s Cancer Society, for example, which as we’ve seen operates a very lucrative business in that country selling its own brand of sunscreen lotions, implies on its website that sunscreen protects against melanoma:
“New Zealand has the highest rate of melanoma in the world, and other skin cancers are also very common. You can help reduce your risk of skin cancer by using sunscreen the right way.”[47]
If New Zealand’s Cancer Society didn’t have the reputation of a major medical charity to save them, they’d probably be at risk in my view of a false or misleading advertising prosecution – especially given the deadly impact of the claims.
Similar claims are made in Australia: “Skin cancer is one of the most preventable cancers, yet Australian adolescents have by far the highest incidence of malignant melanoma in the world,” a spokeswoman for Sunsmart Australia said in a recent news release.[48]
On the basis of the science above, why are health agencies continuing to make these statements?
An Australian study often quoted by supporters of sunscreens was published in 2011.[49] It looked at an initial five year trial period and then a 10 year follow up, and found that regular users of broad spectrum sunscreens were less likely to develop primary melanomas. Critics, however, remain unconvinced.
“The study had serious limitations: the authors admitted that the results were marginally statistically significant; intervention sites of sunscreen application were chosen for nonmelanoma skin cancer and excluded the trunk and extremities, where melanomas often occur; and the entire body was analysed for melanomas, not just the intervention site. Thus, despite providing some of the first evidence supporting sunscreen’s ability to prevent melanoma, these results are controversial and by no means conclusive.”[50]
In addition, a follow-up analysis published in the same journal working from the same Australian data actually found a higher rate of melanomas on areas that had been allegedly ‘protected’ by broad spectrum sunscreen.
You’ll recall the studies quoted earlier where schoolchildren who used sunscreen regularly in controlled studies were actually more likely to develop melanoma precursors. The reason for this can possibly now be seen in context. By building a sun-safety message anchored primarily in the need for pharmaceutical companies to make a buck out of sunscreens, we have created a false but widespread public belief that sun exposure is easily controlled through sunscreens. It just isn’t true. There are screeds of studies that prove sunscreens are effective at protecting against ageing of the skin, and against largely harmless forms of skin cancer. But let’s face it, the real reason most people slop on the sunscreen is because they fear the Big-M that the media constantly warn them about.
So what happens when people swap their natural defence against melanoma (a suntan), for a solution obtained from a bottle that turns out to be ineffective? Melanoma rates go up despite increasing usage of sunscreens, and that’s exactly what has happened since 1935.
The weight of scientific evidence overwhelmingly suggests sunscreens don’t protect you from melanoma and, worse, may actually increase your risk of developing it. In addition, because sunscreens are so good at blocking the vitamin D producing UVB rays, they may actually be seriously increasing your risk of dying from melanoma if you do develop it, because your body now lacks D’s cancer-fighting protection.
Some of the same pharmaceutical companies who sold you the ineffective sunscreen in the first place will also make money from the hugely expensive cancer drugs or other medication you might later need.
It gets worse, however. You’ll recall that sunscreens have an SPF factor, supposedly to reassure you of their relative strength and duration of protection. What most people don’t know is that the SPF relates only to UVB radiation, not UVA. That means your SPF30+ sunscreen “might” give you all day protection from UVB (if applied under laboratory conditions), but it’s doing nothing of the sort against deadly UVA rays.
“But they’re all broad-spectrum sunscreens now, aren’t they?” you ask. Only to a point: studies have shown that titanium dioxide, the most effective block against UVA known to man, was only able to muster up a protection factor of 12 for UVA radiation when used as directed in a recent experiment,[51] yet the same mineral managed to hit an SPF of 38 in another experiment. To draw an analogy, relying on a broad spectrum sunscreen to protect you from cancer-causing radiation is like playing Russian Roulette using a gun where four of the six chambers contain live bullets. And they don’t tell you that on the back of the bottle.
Scientists actually don’t know how much UVA is being blocked, and sunscreen manufacturers are arguing amongst themselves about the problem:
“To this day, SPF lotions vary greatly in their broad-spectrum protection,” says a Procter & Gamble briefing. “Many SPF products claiming to reduce exposure to UVA do not even contain an FDA-recognized UVA sunscreen, such as avobenzone or zinc oxide.”[52]
Now, here’s the important bit:
“Currently, there is no universal test method or standard product label to indicate the level of UVA protection.”
You read it right. We don’t know how effective UVA sunscreens actually are. The labels on the bottle promise the earth, but it’s unclear how much protection they are really delivering.
“Despite these variances in protection,” reassures Procter & Gamble, “experts still agree that everyone should practice sun-safe strategies.”
California-based dermatologist Lawrence Samuels is another bemoaning the lack of hard and fast data on UVA protection:
“Unfortunately, at the present time there is no measure to quantify the effectiveness of a sunscreen’s ability to block UVA rays. It is well known that chemical sunscreen ingredients that block UVA rays are somewhat unstable when exposed to UV rays and oxygen (air). This is further complicated by the fact that we do not have the ability to measure the stability or effectiveness of chemical sunscreens that block UVA rays.”[53]
When you factor in that most of us don’t use as much sunscreen lotion as manufacturers recommend, the protection factors (for what they’re worth) will be lower again.
In other words, let the user beware. If you still think your sunscreen is truly a broad spectrum lotion protecting you from UVB and UVA radiation, you may be endangering yourself and your family. The effect of using a sunscreen that, at best, might only be shielding 25% of UVA radiation and 95% of UVB, is similar to being bombarded with UVA rays on a sunbed, which health officials are very vocal about, incidentally.
Further proof that natural tanners do better than sunblockers comes from a 2009 study by the US Food and Drug Administration’s Dianne Godar and others,[54] which found indoor office workers have higher melanoma rates than outdoor workers – a finding that supports Leeds University’s Julia Newton-Bishop’s conclusion that people who get outside in the sun at weekends are less likely to get melanoma than people who stay out of the sun.
“Paradoxically,” reports Godar’s study, “although outdoor workers get much higher outdoor solar UV doses than indoor workers get, only the indoor workers’ incidence of cutaneous malignant melanoma (CMM) has been increasing at a steady exponential rate.”
“The Godar paper argues that the environment we have created living indoors behind glass since the beginning of the 20th century, which allows exposure to UVA, but not UVB which synthesises vitamin D, is responsible for the epidemic of melanoma,” explains Robert Scragg, a vitamin D expert at New Zealand’s University of Auckland. Office buildings, homes and car windows have been allowing burning UVA radiation through while blocking UVB rays – which actually help generate protective vitamin D3 if they can reach your skin.
The US Food and Drug Administration study found vitamin D3 – created in the skin by suntanning – acts like a timebomb when it is absorbed by melanoma cancer cells.
“Outdoor exposures include UVB (290–320 nm) radiation, so that previtamin D3 and thermal conversion to vitamin D3 can occur in the skin. Vitamin D3 can then be converted to its most hormonally active form, 1a,25-dihydroxvitamin D3 or calcitriol, which kills melanoma cells and SCC (squamous cell carcinoma),” the Godar study reports.
The D3 attaches itself to melanoma cancer cells and explodes them.
“Calcitriol can control or eliminate melanoma cells by binding to the vitamin D3 receptor (VDR) on the nuclear membrane signalling for either growth inhibition or cell death via apoptosis, while it protects normal melanocytes from apoptosis.”
Apoptosis is the way the body normally destroys cancer cells safely, but cancers spread when apoptosis isn’t working properly. Vitamin D3 appears to power-up the body’s natural cancer-destroying mechanisms.
We spend our working lives indoors, and the only times we go out in the sun we slap on a chemical cocktail capable of severely restricting vitamin D production.
Little wonder that an Austrian scientific study in the late nineties found users of sunscreens were a whopping three and a half times more likely to develop melanomas than regular unprotected sunbathers:
“The factor most significantly associated with increased melanoma risk was the use of sunscreens. Subjects who often used sunscreens had an increased odds ratio (OR) of 3.47 (95% confidence interval [CI]1.81-6.64) compared with subjects who never used sunscreens (P = 0.001), after adjustment for sex, age and other significant sunlight-related factors. Skin colour and higher numbers of sunbaths were significant protective factors.”[55]
The Austrian team found that people who sunbathed more than 30 times a year reduced their risk of melanoma by a massive 91%. The only thing that ramped their risk right up again was if they got sunburnt doing it.[56]
A recent Swedish study, based on the knowledge that sunburn can lead to melanoma, examined society’s most vulnerable – our children. Staggeringly, they found children whose parents regularly slopped sunscreen on them were more likely to get sunburnt:
“Sunscreen was an independent risk factor of being sunburnt between 2 and 7 years of age (not or seldom using sun screen was protective)… Swedish children are frequently sunburnt and children living in the south are more sunburnt than those in the north. Sunscreens that were seldom used or not used at all were found to be protective. These results support previous reports that photosensitive skin type is an important risk factor for suffering sunburn as a child and therefore increases the risk of cutaneous malignant melanoma.”[57]
The Monty Python team could not have said it more deftly: “Sunscreens that were…not used at all were found to be protective”.
In other words, parents who encouraged their children to tan naturally and gradually, without sunscreen, turned out to be more responsible than parents who followed official policy advice to slather on the sunscreen.
There are many scientists now daring to suggest that the sunscreen, sunsmart emperor has no clothes.
“Many primary care providers advise patients to use sunscreen as a means to reduce their risk for skin cancer, especially cutaneous malignant melanoma (CMM),” writes Dr Margaret Planta.[58] “Despite the availability and promotion of sunscreen for decades, the incidence of CMM continues to increase in the U.S. at a rate of 3% per year. There currently is little evidence that sunscreens are protective against CMM. A number of studies suggest that the use of sunscreen does not significantly decrease the risk of CMM, and may actually increase the risk of CMM and sunburns.”
Planta warns “providers may need to alter their advice regarding sunscreen use for CMM prevention”.
In 2006, the US Environmental Protection Agency put it on the record with a bald statement of fact, “there is no evidence that sunscreens protect you from malignant melanoma.”[59]
Dr Planta cites more evidence, like the fact that residents of cooler northern US states like Delaware have a higher incidence of melanoma than sunnier southern states like Texas, which again suggests a greater and more regular sun exposure might actually protect against melanoma. Planta, incidentally, still insists sunscreens are necessary, but that the public need to be fully informed of their weaknesses.
“Future studies with humans,” write Burnett & Wang in the conclusion of their own report, “will need to be conducted under real world conditions with modern sunscreens, before we can determine definitively the safety and efficacy of sunscreen.
“However, none of the data published to date conclusively demonstrate adverse effects on the health of humans from the use of sunscreens.”
Dermatologists will frequently tell patients, “by the time you have a tan, the sun has already caused DNA damage inside you”. Statements like this take a significant role in sunsmart messaging. However, whilst true, they are not the whole truth. Getting a tan is the body’s response to UVB radiation – our DNA is actually programmed to repair the “damage” caused by UVB and to manufacture a protective tan as a result. Without the damage, the DNA won’t flip the switch to activate the tan.
Further scientific evidence indicating that dermatologists may not have the full story emerged in a study published February 2012, in the journal Mutation Research.[60] Scientists discovered vitamin D actually prevents DNA from being damaged by free radicals, and maintains genetic integrity. The vitamin also regulates the growth rate of cells and appears to “reduce oxidative damage in humans.”
“Both animal studies and cell culture studies show that vitamin D treatment drastically reduced oxidative stress damage and chromosomal aberrations, and prevented telomere shortening and inhibiting telomerase activity, which also suggested that vitamin D may extend lifespan in humans,” reported journalist David Liu of the findings.[61]
All of these things are what you would expect to find in a complex biological system where life has been reliant on the sun for millions of years. And so far, sun tans are looking a lot more protective against deadly skin cancers than anything humans have devised in the sunsmart arsenal. Maybe the natural response was the best after all.
After all, Cancer Research UK has announced “Over the last 25 years, rates of malignant melanoma in Britain have risen faster than any of the most common cancers.” Melanoma’s drag race up the fatality charts, then, has coincided with a similar mass uptake of sunscreens over the same period.
So what causes melanoma? A cynic at this point might be muttering “sunscreens”, and for all we know that could be true. However, scientists have found some significant risk factors that point to whether you are more likely to develop melanoma.
They include:
Fair skin (29% increase when compared against olive or brown-skinned people)
Very fair skin (183% increase in risk)
Blue/grey eyes (71% increase in risk compared with brown eyes)
Green/hazel eyes (24% increase in risk)
Blonde hair (76% increase in risk compared with black or brown haired people)
Red hair (185% increase in risk)
Able to get moderately tanned (31% increase in risk compared to people who easily tan deeply)
Mild or occasional tans (88% increase in risk)
No suntan at all, or freckled (124% increase in risk)
Additionally, your burn ratio is important. People who go brown without burning had no increase beyond the average risk, but for others:
Mild burning followed by a tan (14% increase in risk)
Painful sunburn followed by peeling (113% increase in risk)
Severe sunburn with blistering (114% increase in risk)
Sunburn before the age of 20 (24% increase in risk compared with people never sunburnt)
Sunburn since 20 (56% increase in risk)
The University of Leeds research unit discovered something else as well:
“We had known for some time that people with many moles are at increased risk of melanoma,” Professor Julia Newton-Bishop explained, but “in this study we found a clear link between some genes on chromosomes 9 and 22 and increased risk of melanoma. These genes were not associated with skin colour.”[62]
It was the first time science had found a genetic link to melanoma that did not involve hair, eye or skin colour. In this case, the genes influenced the number of moles a person has, and hence the number of pre-existing stepping stones that melanoma could spring from. The study determined that at least five genes exist that have an impact on melanoma risk, and most people in the world are carrying at least one of these genes. If you happen to be the lemon in the one-armed-bandit lottery and find you are carrying all five genes, your risk of developing melanoma is 800% higher than a person carrying none.[63]
Here’s something else to think about: if you live in a high UV area like Queensland, sunburn easily or get skin cancer, which has a tiny mortality rate, a new study out of Australia indicates your risk of then developing pancreatic cancer (mortality rate 95% within a year, the remaining 5% soon after) is cut in half.[64] Most people survive breast cancer. The vast majority survive skin cancer. But you don’t walk away from pancreatic cancer.
More people die each year from pancreatic cancer than skin cancer, it is the world’s fourth most deadly cancer measured by number of deaths. Recent high profile victims include Apple co-founder Steve Jobs and actor Patrick Swayze. If it was likely that sunbathing would increase your risk of skin cancer, but reduce your risk of pancreatic cancer by 49%, how would you weigh your relative risk on this?
Tough question, but it’s the kind we need to be asking ourselves because we don’t live in a perfect world, and everything involves a trade-off of some kind.
There’s something else about the pancreatic cancer study that’s confusing researchers: is it vitamin D lowering the risk in this case, or is it sunlight itself? The implications of that are that there may be something protective in the way the human body processes UV radiation that mere vitamin D supplements can’t replicate.
Their logic for saying this is that areas with the highest UV radiation in Australia have the lowest rates of pancreatic cancer, but that some studies have found no impact of vitamin D on this particular cancer.
Then there’s another interesting revelation: sunburn might not be the cause of melanoma, merely an indicator that you are prone to melanoma. It seems like an odd thing to say, but a recent study reported:[65]
“Unfortunately, some aspects of the promotion and analysis of sunscreen use are controversial. Many take the perspective that if sunburns are strongly associated with the development of melanoma, and sunscreens prevent sunburn, then sunscreens will prevent melanoma.
“However…it is likely that sunburn is a clear indicator of the interaction between excessive sun exposure and a susceptible phenotype – that is, severe solar exposure to skin unaccustomed to it – rather than a direct cause of melanoma and basal cell carcinoma.”
In other words, it is not that the sunburn necessarily causes the cancer, it’s just that people most susceptible to skin cancer burn more easily.
What then, can we take away from all this?
That sunscreens are excellent at helping prevent solar aging of the skin, and squamous cell carcinomas.
That there is currently no evidence that sunscreens are of any use at all in the fight against deadly skin cancers like melanoma and basal cell carcinoma.
That there is evidence people who regularly use sunscreen are paradoxically at a much higher risk of developing melanoma.
That if you sunburn easily or fall into a melanoma risk group (fair skin, blue or green eyes etc), it is very important that you do not sunburn.
That sunbathing without sunscreen during summer, but importantly also without burning, confers greater protection against melanoma than using sunscreen, but that this benefit does not exist for high risk individuals, who should use vitamin D supplements rather than sunlight.
That, used correctly, sunscreens make it impossible for your body to absorb healthy amounts of vitamin D.
That, seeing as most people don’t use sunscreens correctly, those users are still getting some, if not the optimum amount, of vitamin D in summer.[66]
The inconvenient truth about sunscreens, melanoma and cancer generally appears to be this: there is no easy solution. If you want youthful radiant skin, the price of beauty appears to be a much higher risk of breast, colon or other cancers of the internal organs, heart disease, Alzheimer’s, multiple sclerosis, mental illness or a range of other nasties we’ve covered off in this book.
In short, it’s a trade-off. The less sunlight you get, the happier your dermatologist will be, but the wealthier your oncologist, cardiologist and psychotherapist might become.
So what if you are one of those people who burns easily or who – despite what you’ve read here about the natural benefits of UV – doesn’t want to spend time in the sun – how do you get sufficient vitamin D? As we’re about to see, there are some alternative options.
[2] A 2005 study found PABA caused thyroid cancer in rats, “Promotion of thyroid carcinogenesis by para-aminobenzoic acid in rats initiated with N-bis(2-hydroxypropyl)nitrosamine”, Hasumara et al, Toxicological Sciences, 2005 Jul;86(1):61-7. Epub 2005 Apr 20
[3] Other countries, like the UK, Europe, New Zealand and Australia, in some cases permit other compounds to be used in sunscreens that are not approved for human use in the USA.
[4] Also known on labels as Butyl Methoxydibenzoylmethane
[6] “Metabolism of 2-hydroxy-4-methoxybenzophenone in isolated rat hepatocytes and xenoestrogenic effects of its metabolites on MCF-7 human breast cancer cells”, Nakagawa & Suzuki, Chem Biol Interactions Journal, 2002; 139:115-128. See also “UV filters with antagonistic action at androgen receptors etc”, Ma et al, Toxicological Sciences, 2003; 74:43-50. See also “Additive estrogenic effects of mixtures of frequently used UV filters on pS2-gene transcription in MCF-7 cells,” Heneweer et al, Toxicol Appl Pharmacol 2005; 208:170-177
[8] “Estrogenic activity and reproductive effects of the UV-filter oxybenzone (2-hydroxy-4-methoxyphenyl-methanone) in fish”, Coronado et al, Aquatic Toxicology, Volume 90, Issue 3, 21 November 2008, Pages 182–187
[9] “Safety of Oxybenzone: Putting Numbers Into Perspective”, Wang et al, Archives of Dermatology, 2011;147(7):865-866. doi:10.1001/archdermatol.2011.173
[10] “Altered UV absorbance and cytotoxicity of chlorinated sunscreen agents”, Sherwood et al, Journal of Cutaneous and Ocular Toxicology, 2012, January 18, http://www.ncbi.nlm.nih.gov/pubmed/22257218
[11] Free radicals are loose electrons within an atom or molecular structure that makes the structure “reactive” until it finds equilibrium, usually by breaking another nearby chemical bond to restore its positive or negative charge to neutral. These things are all well and good until the structure they react with is a cell within your body, because the resulting damage can cause cancer or interfere with other body functions. We use antioxidants to try and mop up these free radicals by providing them with something to bind with that isn’t part of you, but it’s hit and miss. There is no guarantee that free radicals created by UV breaking down sunscreen, will necessarily bind with antioxidants – like a lightning bolt in search of the quickest route to the ground, a free radical will break whatever is easiest and closest at the relevant moment.
[13] “Sunscreen enhancement of UV-induced reactive oxygen species in the skin”, Hanson et al, Free Radical Biology and Medicine, Volume 41, Issue 8, 15 October 2006, Pages 1205–1212
[14] “Sunscreen – a catch 22”, Blum & Larsen, Young Scientists Journal, 2010, issue 8:11-14
[17] “UV irradiation-induced zinc dissociation from commercial zinc oxide sunscreen etc”, Martorano et al, Journal of Cosmetic Dermatology, vol 9, issue 4, Dec 2010:276-286
[18] “DNA damaging potential of zincoxide nanoparticles in human epidermal cells,” Sharma et al, Toxicology Letters, Volume 185, Issue 3, 28 March 2009, Pages 211–218
[19] “Ultraviolet radiation reports shine light on how pediatricians can help patients avoid skin cancer,” Sophie Balk MD, American Academy of Pediatrics, 2011
[20] “Exploring the safety of nanoparticles in Australian sunscreens”, Faunce, International Journal of Biomedical Nanoscience and Nanotechnology, Vol 1, no. 1, 2010:87-94, doi 10.1504/IJBNN.2010.034127
[21] “Evaluation of percutaneous absorption of the repellent diethyltoluamide and the sunscreen ethylhexyl p-methoxycinnamate-loaded solid lipid nanoparticles: an in-vitro study,” Puglia et al, J Pharm Pharmacol. 2009 Aug;61(8):1013-9
[23] “Impact of prenatal exposure to piperonyl butoxide and permethrin on 36-month neurodevelopment”, Horton et al, Pediatrics. 2011 Mar;127(3):e699-706 http://www.ncbi.nlm.nih.gov/pubmed/21300677
[25] A study published May 2012 has followed the Pediatrics results up, and found PBO damages “critical neurological development”, see “The Insecticide Synergist Piperonyl Butoxide Inhibits Hedgehog Signaling: Assessing Chemical Risks,” Wang et al, Toxicological Sciences, (2012) doi: 10.1093/toxsci/kfs165http://toxsci.oxfordjournals.org/content/early/2012/05/03/toxsci.kfs165.short
[26] On the other hand, scientists now know that piperonyl butoxide is also “immunotoxic” to fish, see “Immunotoxic and cytotoxic effects of atrazine, permethrin and piperonylbutoxide to rainbow trout following in vitro exposure,” Shelley et al, Fish & Shellfish Immunology, Volume 33, Issue 2, August 2012, Pages 455–458
[30] “Nanoparticles Used in Common Household Items Cause Genetic Damage in Mice,” ScienceDaily Nov. 17, 2009
[31] As displayed in the ingredients lists on the NZ Cancer Society website, http://www.cancernz.org.nz/products/technical-info/ as retrieved in June 2012
[33] “Photodamage of the skin: protection and reversal with topical antioxidants”, Burke, K E. J Cosmet Dermatol. 2004 Jul;3(3):149-55
[34] “Active ingredients in sunscreens act as topical penetration enhancers for the herbicide 2,4-dichlorophenoxyacetic acid”, Pont et al, Toxicology & Applied Pharmacology. 2004 Mar 15;195(3):348-54
[35] “UV protection and sunscreens: What to tell patients”, Jou et al, Cleveland Clinic Journal of Medicine, Vol 79, number 6, June 2012, pp427-436
[36] “Sunscreen use and malignant melanoma”, Westerdahl et al, International Journal of Cancer, 1 July 2000, Vol 87, issue 1, pp145-150
[39] “Serum 25-Hydroxyvitamin D3 Levels are Associated With Breslow Thickness At Presentation and Survival From Melanoma”, Newton-Bishop et al, Journal of Clinical Oncology, 21 September 2009, DOI:10.1200/JCO.2009.22.1135
[40] Peak UV levels in New Zealand and Australia are 40% higher than peak levels in the UK or North America, according to the official position statement on UV and cancer published by the New Zealand Government’s Ministry of Health
[41] A cautionary note. The protective effect of sunbathing did not extend to people with freckles, or photo sensitive skin. A common sense approach suggests vitamin D supplements are a better bet for those individuals.
[42] In the interests of balance, it is worth pointing out that our sun has been more active over the past century than in the previous one thousand years. That was announced by the Max Planck Institute for Solar System Research in Germany in 2004 and reported in The Telegraph, 19 July 2004.
[43] “UV Protection and Sunscreens”, Jou et al, Cleveland Clinic Journal of Medicine, Vol. 79, No. 6, June 2012
[44] Ibid, sub-referencing “Sunscreen abuse for intentional sun exposure” by Autier, P. Br Journal of Dermatology 2009; 161(suppl 3):40-45
[45] “Prolonged prevention of squamous cell carcinoma of the skin by regular sunscreen use”, Van der Pols et al, Cancer Epidemiol Biomarkers Prev 2006;15:2546-2548
[46] “The Good, the Bad, and the Ugly of Sunscreens,” M Berwick, Clinical Pharmacology & Therapeutics, Jan 2011, doi:10.1038/clpt.2010.227
[48] “Dark Side of Tanning Campaign conveys deadly message to young Victorians this summer”, Sunsmart Australia news release, 2 December 2010
[49] “Reduced Melanoma after Sunscreen Use”, Green et al, Journal of Clinical Oncology, 2011; 29:257-263
[50] “UV Protection and Sunscreens etc”, Jou et al, citing a follow up response, “Increased Melanoma After Regular Sunscreen Use?”, Goldenhersh & Koslowsky, Journal of Clinical Oncology, 2011, 29:e557-e558
[54] “Increased UVA exposures and decreased cutaneous Vitamin D(3) levels may be responsible for the increasing incidence of melanoma”, Godar et al, Medical Hypotheses. 2009 Apr;72(4):434-43
[55] “Phenotypic markers, sunlight-related factors and sunscreen use in patients with cutaneous melanoma: an Austrian case-control study”, Wolf et al, Journal of Melanoma Research, 1998 Aug;8(4):370-8, http://www.ncbi.nlm.nih.gov/pubmed/9764814?dopt=Abstract
[56] In contrast to the impact of sunbathing on reducing melanoma risk, the current ‘darling’ of dermatology is aspirin, with a number of reports suggesting low-dose aspirin daily can cut your risk of melanoma. If you read the following study, you’ll see the risk reduction is 13% over a seven year period. Not quite a 91% risk reduction! See “Nonsteroidal anti-inflammatory drugs and the risk of skin cancer: A population-based case-control study,” Johannesdottir et al, Cancer, online 29 May 2012, doi: 10.1002/cncr.27406
[58] “Sunscreen and Melanoma: Is Our Prevention Message Correct?”, Margaret B. Planta MD, Journal of the American Board of Family Medicine, Nov-Dec 2011, vol 24 no. 6, 735-739 doi: 10.3122/jabfm.2011.06.100178
[60] “Does vitamin D protect against DNA damage?,” Nair-Shalliker et al, Mutation Research, 2012 May 1;733(1-2):50-7. See also “The Role of the Vitamin D Receptor and ERp57 in Photoprotection by 1α,25-Dihydroxyvitamin D3,” Sequiera et al, Molecular Endocrinology February 9, 2012 me.2011-1161. See also “Vitamin D and skin cancer,” Dixon et al, Human Health Handbooks no. 1, 2012, Volume 2, Part 5, 394-411, DOI: 10.3920/978-90-8686-729-5_24
[61] “Vitamin D may indeed help fight cancer,” by David Liu, Food Consumer.org, 27 April 2012
[62] “Moles and melanoma – researchers find genetic links to skin cancer”, news release from Leeds Institute of Molecular Medicine and the Cancer Research UK Centre, 6 July 2009
[63] In late 2011, the same research team uncovered three more genes adding to the risk. One DNA fault is linked to narcolepsy (suddenly falling asleep), the second is a faulty gene that fails to repair damaged DNA in cells as it should, and the third risk factor is in a faulty gene that is supposed to prevent cancerous cells from spreading. If you are carrying all three of these gene faults, your risk of developing melanoma in your life is one in 46. See “Genome-wide association study identifies three new melanoma susceptibility loci”, Barret et al, Nature Genetics [doi: 10.1038/10.1038/ng.959]
[64] “Sun sensitivity linked to decreased pancreatic cancer risk, study suggests,” Amanda Chan, Huffington Post, June 20, 2012, http://www.huffingtonpost.com/2012/06/20/sun-pancreatic-cancer-risk-sensitivity-uv-rays-vitamin-d_n_1609095.html
[65] “The Good, the Bad, and the Ugly of Sunscreens,” M Berwick, Clinical Pharmacology & Therapeutics, Jan 2011, doi:10.1038/clpt.2010.227
[66] It is not true to claim, as some do, that slip, slop, slap has not impacted vitamin D levels, as this snippet from a bowel cancer study illustrates: “Our findings are consistent with a recent analysis of the National Health and Nutrition Examination Survey (NHANES), which found a low mean plasma 25(OH)D level of 24 ng/mL among 13,369 participants between 2001 and 2004.1 This represented a marked decrease from NHANES III (1988 to 1994), when the mean 25(OH)D level was 30 ng/mL. Potential explanations for the rise in vitamin D insufficiency include increasing use of sunscreen for skin cancer prevention, decreased outdoor activity, and the rising prevalence of obesity.” See http://jco.ascopubs.org/content/29/12/1599.full
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