By Dr. Mercola
Vitamin D, often referred to as "the sunshine vitamin," is different
from other vitamins in that it influences your entire body.
And, while scientists refer to vitamin D
as a vitamin, it is actually a steroid hormone obtained from sun
exposure, food sources and supplementation. Vitamin D receptors have
been found in almost every type of human cell, from your brain to your
bones.
Unfortunately, dermatologists and the media do the public a great
disservice by recommending avoiding the sun to decrease skin cancers.1,2
This is because these "experts" fail to realize that vitamin D deficiency not only raises your risk of skin cancer3 but many of the most common cancers as well, which claim far more lives than the deadliest skin cancer, melanoma.
Breast4 and prostate5,6
cancers are just two examples where low vitamin D renders you more
vulnerable to more aggressive forms of the disease. Low vitamin D also
raises your risk for heart disease, diabetes, osteoporosis and other chronic diseases.
The scientific evidence, now running in excess of 34,000 studies, details the many benefits of UV exposure, both for vitamin D production and other benefits that are completely unrelated to vitamin D.
The most important thing you can do to prevent skin cancer is to
spend a sufficient amount of time in the sun as frequently as possible,
ideally close to daily to maintain an optimal vitamin D level.
A primary risk factor for skin cancer is intermittent overexposure,
not sensible exposure. Appropriate sun exposure means, first and
foremost, avoiding sunburn. As long as you avoid sunburn you are getting
the benefits of sun exposure.
Sunscreen Chemical Is Lethal to Horseshoe Crabs
Avoid shielding yourself from the sun's rays by slathering on
chemical sunscreens, many of which have been linked to an increased risk
of skin cancer, as noted by clinical laboratory scientist Elizabeth
Plourde, Ph.D.,7 in the video above. Sunscreens have also been implicated in the destruction of corals and other sea life.
A recent symposium on emerging environmental contaminants highlighted
the environmental dangers associated with widespread sunscreen use.
According to University of Delaware marine biologist Danielle Dixson,
the chemical oxybenzone in sunscreens is lethal to horseshoe crab eggs.
In Delaware, beach season coincides with the spawning season of
horseshoe crabs, and since they lay their eggs in the sand in shallow
water, they're particularly vulnerable to chemical contaminants
introduced by beachgoers.
Researchers estimate sunscreen-wearing beachgoers introduce as much
as 6,000 metric tons of sunscreen into the world's oceans each year. As
reported by Cape Gazette:8
"'Sunscreen exposure strongly influences the development, growth
and survivorship of the horseshoe crab egg and larvae,' [Dixon]
concluded …
The chemical found in Hawaiian Tropic used in Dixson's study is
oxybenzone, which has been found to alter the DNA of coral, increase
susceptibility to coral bleaching and disrupt the endocrine systems of
marine animals.
Research has found the chemical impacts aquatic life at a
concentration of 62 parts per trillion — the equivalent of one drop of
water in about six Olympic-size pools, Dixson said."
Sunscreens Contain Many Potentially Hazardous Chemicals
While some sunscreen manufacturers have switched from oxybenzone to
avobenzone, researchers like Dixon note no studies have been done to
confirm whether avobenzone is actually a safer choice. Chances are, it's
not.
Disturbingly, recent research by the Center for Disease Control and
Prevention found 96 percent of the U.S. population has oxybenzone in
their bodies, and this chemical is a known endocrine disruptor linked to
reduced sperm count in men and endometriosis in women.9
Disturbingly, at least nine of the sunscreen ingredients the U.S.
Food and Drug Administration (FDA) has approved are known endocrine
disruptors.10
Aside from oxybenzone — which is found in 70 percent of sunscreens —
other commonly used chemicals that can enter your bloodstream and can
cause toxic side effects, including hormone disruption, include but are
not limited to:11,12
Octyl methoxycinnamate (OMC)
Para-aminobenzoic acid (PABA)
Octyl salicyclate
Phenylbenzimidazole
Octocrylene
Octisalate
Dioxybenzone
Menthyl anthranilate
Homosalate
Octinoxate
Cinoxate
Parabens
Many sunscreens also contain vitamin A and/or its derivatives, retinol and retinyl palmitate,
which have been linked to an increased risk of skin cancer by
increasing the speed at which malignant cells develop and spread.
Beware of Nanoparticles
Spray-on sunscreens13
pose an additional hazard by releasing toxic particles into the air.
The FDA has previously expressed concern that inhaling these products
may be risky, especially to children, and has warned parents to avoid
spray-on sunscreens.14,15
The two agents of greatest concern are zinc oxide and titanium dioxide,
as these are the two most often used in spray-on sunscreen products.
These two minerals are the safest topical sunscreen agents around, but
inhaling them is a whole different story.
Most studies to date have shown that zinc oxide and titanium dioxide are
safe and unlikely to penetrate your skin when applied topically, as
long as they are not nanosized.
But when these minerals are inhaled, they have been shown to irritate
lung tissues and potentially lead to serious health problems,16 and the finer the particles, the worse their effects appear to be.
The International Agency for Research on Cancer (IARC) has classified
titanium dioxide as a "possible carcinogen" when inhaled in high doses.17 According to IARC:18
"Titanium dioxide causes varying degrees of inflammation and
associated pulmonary effects including lung epithelial cell injury,
cholesterol granulomas and fibrosis. Rodents experience stronger
pulmonary effects after exposure to ultrafine titanium dioxide particles
compared with fine particles on a mass basis."
Safe Versus Unsafe Titanium Dioxide and Zinc Oxide
Most nanoscale particles (microscopic particles measuring less than 100 nanometers)19 found in American sunscreens are either titanium dioxide or zinc oxide.20
Animal research has shown that inhaled nanoparticles can reach all
areas of your respiratory tract and, since your lungs have difficulty
clearing small particles, they may be allowed to pass into your
bloodstream.
Other studies have proven some nanoparticles are even able to cross
your blood-brain barrier. If allowed to enter your lungs or penetrate
your skin, nanoparticles therefore have the potential to cause
widespread damage to your cells and organs, immune system, nervous
system, heart and brain.21,22
Some scientists postulate that the toxic effects of nanoparticles
relate to their size being in the range of a virus, which may trigger
your body's immune response.23
Inhaling higher amounts of zinc oxide can also lead to "metal fume fever,"24
characterized by chest pain, cough, dyspnea, reduced lung volumes,
nausea, chills, malaise and leukocytosis. One animal study found zinc
oxide nanoparticles to be cytotoxic, interfering with zinc homeostasis,
elevating zinc levels and resulting in apoptosis (cell death).25
An Indian study concluded that zinc oxide particles cause toxicity in
human lung cells possibly through "stress-induced apoptosis."26
Human studies are sorely lacking as to the health effects of inhaling
of zinc oxide particles, especially at lower levels, such as from brief
exposure to sunscreen spray. However, using these spray-on products are
clearly an unnecessary risk since safer options are readily available.
Your safest bet is to use topical zinc oxide or titanium dioxide that
does not contain nanosized particles.
Sun Avoidance Promotes Early Death
One of the most compelling reasons for getting regular, sensible sun exposure
on bare skin is that it promotes optimal physical and psychological
health and helps prevent chronic diseases of all kinds. As noted in a
scientific review27
by dermatologist Dr. Richard Weller, sun exposure has cardiovascular
benefits independent of vitamin D, and cardiovascular disease is a far
greater public health problem than skin cancer.
In fact, research suggests your risk of dying from heart disease or
stroke is 800 percent greater on average than your risk of dying from
skin cancer.28
One of the key messages in Weller's paper is that public health
messages really should be determined based on all-cause mortality, not a
singular disease.
"Sunlight is a risk factor for skin cancer, but sun avoidance may
carry more of a cost than benefit for overall good health," he writes.
Another study29 published in the journal Public Health Nutrition in 2012 also concluded that:
"The overall health benefit of an improved vitamin D status may be
more important than the possibly increased CMM (cutaneous malignant
melanoma) risk resulting from carefully increasing UV exposure.
Important scientific facts behind this judgment are given."
Even though Weller is ahead of the pack in recognizing the importance of
sun exposure, he and most other physicians don't understand why this is
so. There are many reasons, but two large ones are:
Exposure to the sun increases nitric oxide
production, which will relax blood vessels, lower blood pressure and
decrease platelet activation, making your blood thinner and less likely
to clot and form a stroke or heart attack. Nitric oxide will also
improve your immune function.
Red and infrared rays are rarely discussed but recent research has
shown that red at 660 nm and near infrared at 830 nm both have powerful
benefits on improving mitochondrial function. This is because cytochrome
c oxidase, which is one of the electron transport chains in the
mitochondria, are chromophores for those wavelengths and when they
absorb that energy the efficiency of ATP and mitochondrial cellular
energy is increased.
Sun Avoidance Is as Risky as Smoking
A study30,31
driving home this risk-benefit reality was done in Sweden. More than
25,500 Swedish women between the ages of 25 and 64 were followed for 20
years. Detailed information about sun exposure habits and confounding
factors were obtained and analyzed in a "competing risk" scenario.
Overall, women who got regular sun exposure did have a higher risk for
melanoma compared to sun avoiders, but they also had a lower all-cause
mortality risk, likely due to their increased vitamin D levels.
Women with active sun exposure habits ended up having a lower risk of
cardiovascular disease and non-cancer death compared to those who
avoided the sun. According to the authors:
"Nonsmokers who avoided sun exposure had a life expectancy similar
to smokers in the highest sun exposure group, indicating that avoidance
of sun exposure is a risk factor for death of a similar magnitude as
smoking. Compared to the highest sun exposure group, life expectancy of
avoiders of sun exposure was reduced by 0.6 [to] 2.1 years."
In short, if you're concerned about mortality, and not just mortality
from one specific disease (melanoma), the scales are decidedly tipped
toward sun exposure being of tremendous benefit. Five of the many
noteworthy properties of spending some quality time in the sun include:32
Pain-killing (analgesic) properties
Increased subcutaneous fat metabolism
Regulation of human lifespan (solar cycles appear to be able to directly affect the human genome, thereby influencing lifespan)
Daytime sun exposure improves evening alertness
Conversion to metabolic energy (i.e., we may "ingest" energy directly from the sun, like plants do)
Measure Your Vitamin D in Summer and Winter
As a general rule, I recommend measuring your vitamin D level twice a
year, in the middle of the summer and winter, to ascertain your annual
high and low. Ideally, you want your serum 25-hydroxyvitamin D (25(OH)D)
to be between 40 and 65 nanograms per milliliter (ng/mL) year-round.
Anything below 20 ng/mL is considered a serious deficiency state that
increases your risk of both acute and chronic ill health.
When it comes to optimizing your vitamin D through sensible sun
exposure, keep your skin color in mind. African Americans are more prone
to vitamin D deficiencies as they produce less vitamin D3 than do
Caucasians in response to usual levels of sun exposure. As a general
rule, the darker your skin, the more sun exposure you need, and vice
versa.
Remember the absolute best way to optimize your vitamin D level is by
sensible sun exposure. I haven't swallowed oral vitamin D for over 10
years now and my level is rarely below 70 ng/mL, but that is because I
made a conscious effort to move down to Florida and walk in the sun for
90 minutes nearly every day.
I realize that not everyone can do this, and if you can't, then
taking a supplement is likely a wise choice. I just want you to
recognize it is a significantly inferior alternative as you are also
missing out on the nitric oxide, and the red- and near-infrared benefits
from the sun mentioned above.
Reduce Your Risk of Sunburn With 'Internal Sunscreens'
As mentioned, one of the primary risk factors of skin cancer is sunburn,
which is an inflammatory process. Aside from paying careful attention
to covering up before you get burned, you can reduce your risk of
sunburn by eating plenty of antioxidant-rich fruits and vegetables,
and/or taking an astaxanthin
supplement. The latter has been shown to work as an effective internal
sunscreen, protecting your skin from UV radiation damage.
In addition to copious testimonials and anecdotal evidence, scientific studies have substantiated these skin protective effects.33
In one study, subjects who took 4 milligrams (mg) of astaxanthin per
day for two weeks showed a significant increase in the amount of time
necessary for UV radiation to redden their skin. Animal studies lend
further evidence to astaxanthin's effects as an internal sunscreen:
In one study, mice were fed various combinations of astaxanthin,
beta-carotene and retinol for four months. Astaxanthin was substantially
effective in preventing photoaging of the skin after UV radiation, as
measured by markers for skin damage34
A rat study found astaxanthin was found to be 100 times stronger
than beta-carotene and 1,000 times stronger than lutein in preventing
UVA light-induced oxidative stress35
The Journal of Dermatological Science published a study in 2002
finding astaxanthin is able to protect against alterations in human DNA
induced by UVA light exposure36
How to Choose a Safer Sunscreen
There are thousands of sunscreens on the market and it may seem daunting
to find a safe one. The majority of chemical sunscreens contain
endocrine disruptors, which are particularly risky for pregnant women,
infants and small children. These can disrupt growth and development,
cause early puberty and result in small testicle size and low sperm
count in boys. They also have carcinogenic potential.37
Among the worst are those containing oxybenzone, synthetic fragrances
and retinyl palmitate. When choosing a sunscreen, your safest choice is a
lotion or cream with zinc oxide. It's stable in sunlight and provides
the best protection from UVA rays.38 Your next best option is titanium dioxide. Just make sure the product:
Does not contain nano sized particles
Protects against both UVA and UVB rays
Keep in mind that SPF protects only from UVB rays, which are the rays
within the ultraviolet spectrum that allow your skin to produce vitamin
D. The most dangerous rays, in terms of causing skin damage and cancer,
are the UVA rays. Avoid sunscreens with an SPF above 50.
While not intrinsically harmful, the higher SPF tends to provide a false
sense of security, encouraging you to stay in the sun longer than you
should. Moreover, higher SPF typically does not provide much greater
protection. In fact, research suggests people using high-SPF sunscreens
get the same or similar exposure to UV rays as those using lower-SPF
products.
Other Safe Sunning Tips
I recommend spending time in the sun regularly — ideally daily. Sunshine
offers substantial health benefits, provided you take a few simple
precautions to protect yourself from overexposure. Here are my top five
safe sunning tips:
1. Give your body a chance to produce
vitamin D before you apply sunscreen. Expose large amounts of your skin
(at least 40 percent of your body) to sunlight for short periods daily.
Optimizing your vitamin D levels may reduce your risk of many internal
cancers, and actually reduces your risk of melanoma as well. 2. Stay out just long enough for your
skin to turn the very lightest shade of pink. Shield your face from the
sun using a safe sunscreen or hat, as your facial skin is thin and more
prone to sun damage, such as premature wrinkling. 3. When you'll be in the sun for longer
periods, cover up with clothing, a hat or shade (either natural or shade
you create using an umbrella). A safe sunscreen can be applied after
you've optimized your skin's daily vitamin D production, although
clothing is your safest option to prevent burning and skin damage.
Keep in mind that in order for sunscreen to be effective, you must
apply large amounts over all exposed areas of your skin. This means the
product should not trigger skin allergies and must provide good
protection against UVA and UVB radiation. It also should not be absorbed
into your skin, as the most effective sunscreen acts as a topical
barrier. 4. Consider the use of an "internal
sunscreen" like astaxanthin to gain additional sun protection.
Typically, it takes several weeks of daily supplementation to saturate
your body's tissues enough to provide protection. Astaxanthin can also
be applied topically, which is why it's now being incorporated into a
number of topical sunscreen products. 5. Consuming a healthy diet
full of natural antioxidants is another highly useful strategy to help
avoid sun damage. Fresh, raw, unprocessed foods deliver the nutrients
that your body needs to maintain a healthy balance of omega-6 and
animal-based DHA omega-3 oils in your skin, which are your first lines of defense against sunburn.
Vegetables also provide your body with an abundance of powerful
antioxidants that will help you fight the free radicals caused by sun
damage that can lead to burns and cancer.
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