Friday, July 29, 2011

Sunscreen - Bringing Sunscreen Ingredients to Light

Sunscreen sucks... I simply despise the stuff. 

It smells, it’s greasy and it makes me feel slimy when I wear it. Since I wear a sunhat, sunglasses, and usually wear long clothing to cover my skin on sunny days, is it really worth slobbering on sunscreen?

The media tries to persuade us to use sunscreen, supposedly to protect us from skin cancer. But does sunscreen actually prevent cancer? Most importantly, does sunscreen protect against malignant melanoma, the deadliest form of skin cancer?

I also worry, is it really such a great idea to cover ourselves and our children skin with the questionable chemicals in sunscreen? Shouldn’t we be more concerned that chemical sunscreens get absorbed by our skin, which then can effect the rest of our bodies?

And don’t we need sunlight? Since life on earth depends on sunlight...doesn’t that mean that we do too?

The short answer to these questions is there is no “one size fits all solution” to the value or risks of using sunscreen. It really depends on where you live, your skin characteristics, your clothing preferences, and, perhaps most importantly, the wisdom with which you choose your sunscreen.

Is the sun dangerous?... Yes actually.

On April 13, 2011 the International Agency for Research on Cancer (IARC) of the World Health Organization (WHO) classified all categories and wavelengths of Ultraviolet Radiation as a Group 1 carcinogen. This is the highest level designation for carcinogens and means "There is enough evidence to conclude that it can cause cancer in humans".

Skin Cancer

Skin cancer is the most common form of cancer in the United States, accounting for almost half of all cancer cases. There are three major types of skin cancer: squamous-cell carcinoma, basal-cell carcinoma, and malignant melanoma. Of these three, malignant melanoma is by far the most dangerous.

Sunlight is essential to life and sunlight is dangerous... Unravelling the confusion:

Sunlight is the driving source of energy that produces our food, keeps us warm, and produces so much energy that we can even use it to power our homes. While sunlight is essential to life on this planet, there are different components of sunlight that have different effects and risks to human health.

The sun produces the light (electromagnetic radiation) that allows us to see. Visible light exists from deep red to intense purple (like the colors in a rainbow). But what our eyes are tuned to see is only a small slice of the electromagnetic spectrum that arrives from the sun. The sun also produces many other wavelengths of light that we cannot see. Even though we can’t see these other wavelengths, they do effect us. For example, we can feel infrared light as warmth.

Visible light and Infrared light are slices of the electromagnetic spectrum that are not inherently dangerous and yet provide us with essential benefits to survive on earth. The reason these wavelengths of light are not dangerous is because they do not impart enough energy to produce damage to our DNA.

When you move toward higher frequencies on the electromagnetic spectrum, you move into high energy light known as ultraviolet (UV) radiation. UV radiation exists just above the visible color of violet (hence the name ultra-violet). UV light can be helpful or it can be harmful. It all depends on which type of UV radiation.

Types of UV radiation:

The UVA radiation frequency sits just above the visible color of violet and is considered to be “low energy” UV radiation. The next step on the frequency ladder is called UVB radiation, and this is the first level that is energetic enough (called “ionizing radiation”) to cause direct damage to DNA in living things. Any type of radiation that can cause DNA damage has the potential to lead to cancer. Higher still on the electromagnetic spectrum we get to UVC radiation. UVC is more energetic than either UVA or UVB, but since the Earth’s atmosphere filters out virtually all of this very high energy radiation, it is not much of a concern for us, unless you intend to start taking trips into space.
Humans can only see a small slice of the EM spectrum.
The sun bathes us in light from almost the entire spectrum.
How does UVA and UVB radiation affect us? 


UVA radiation causes the body to release stores of melanin (skin pigment) darkening the skin for a short time (on the scale of hours). Our skin’s response to UVA is actually an effort by our bodies to immediately protect itself from damage, as melanin absorbs UV light rather well. Thus, the more melanin released into our skin, the darker our skin becomes and the more short term protection we have against further UV damage. Thus, darker skinned individuals simply burn less by having more protective melanin in their skin, which acts as a sort of natural sunscreen (of about SPF 5 or so).

UVB radiation is responsible for the long lasting increase in melanin called “tanning”. The onset of this increase generally starts around 2-3 days after exposure to UVB light and lasts for a few weeks. UVB radiation is also essential for the body to produce vitamin D, and too little exposure to sunlight can cause a deficiency in vitamin D (leading to rickets, or even a possible increased risk of cancer).


UVA light also penetrates deeply into your skin. This deep penetration of UVA light is primarily responsible for wrinkles, thickening of the skin (that leathery look), and destruction of collagen, elastin, and other natural fibers in the skin. This photoaging effect happens when unprotected skin is exposed to the sun for even short periods of time. Photoaging caused by exposure to UVA light is thought to account for about 90% of the visible signs of aging in skin.

When UVA light contacts your skin it also increases your risk of cancer by generating “free radicals”. Research has found that free radicals have the ability to damage cells in your body which can cause indirect damage to your DNA. This damage has been linked to the development of malignant melanomas, one of the most dangerous and deadly forms of skin cancer.

Exposure to UVB light is what causes sunburns (this happens even on overcast or cloudy days). UVB, considered “ionizing”, is capable of causing direct damage to DNA, which also greatly increases the risk of cancer.

Vitamin D is produced by the body being exposed to UVB radiation but vitamin D can also be supplemented, either through diet or from actual supplements. Since sunscreens that block out UVB also block out natural vitamin D production in the skin, the risk of direct damage from UVB light must be weighed against the benefit of vitamin D production.

For most people, spending just ten minutes in strong sunlight - the kind you get from 10:00 AM to 3:00 PM between April and August in the Northern Hemisphere - will allow your body to make as much vitamin D as you would get from drinking two hundred glasses of milk. This small ten minute exposure, three times a week, should provide more than enough vitamin D for your body.

In areas farther from the equator, there is less intense sunlight (and therefore lower amounts of UVB radiation) during the winter months, so the risks of vitamin D deficiency may become significant even if you stayed outside without any sunscreen during the most sunny part of the day. For those living in these regions it is important to get adequate supplementation with vitamin D though your food (eggs, fortified milk, fatty/oily fish, etc.) or through supplementation (e.g. vitamin D supplements and/or cod liver oil etc). Vitamin D is especially important for pregnant or breastfeeding women and young children, however, it is essential to always consult a doctor before taking any vitamin D supplement because too much vitamin D can cause serious health problems.

When it comes to sunscreens, how do we choose?
Sunblock (usually Zinc Oxide) forms
an opaque barrier protecting us from
damaging UV radiation.
As mentioned above, our bodies produce a natural sunscreen called melanin, one of the primary pigments of the skin. Melanin is an extremely effective and safe form of sun protection (as we would expect from nature) that basically absorbs UV light and (by bonding with oxygen) dissipates the energy as heat.

We have created synthetic chemicals, to try to protect us from damaging UV radiation, called “sunscreen” or “sunblock”. Sunscreen is generally a cream or oil that is applied to the skin that dries or is absorbed into a clear protective layer against UV radiation. Sunblock, however, is a controversial term, as it was once used to mean an opaque protective layer of, usually, zinc oxide. You might even recognize the look of old surfers with their noses covered with zinc oxide sunblock. However, in recent years, clever marketers realized that there is no clear legal definition for “sun block”, and have used this term to imply more protection than their products actually provide.

There are 2 types of synthetic sunscreen - chemical and physical:

Chemical sunscreens are absorbed into the skin and work by absorbing UV light and in some manner degrading that energy. This energy transition takes place primarily by redirecting the energy of the UV light into chemical reactions with the sunscreen chemicals.

Shortcomings of chemical sunscreens

While some chemical sunscreens do protect fairly well against UVB light, and therefore sunburns, they have had increasing reports of insufficient UVA radiation protection. Even though chemical sunscreens do absorb and redirect the energy from some (but not all) UVA light, they often do so by producing “free radicals” which can actually increase the risk of DNA damage and cancer more than unprotected exposure to UVA light.

Unfortunately, in the United States, the cheap chemicals allowed to be used in sunscreen to protect from UVA radiation are not terribly effective. In other words, you won’t get nearly as effective UVA protection as compared to UVB protection. In Europe, there are many more options for adequate UVA protection, however, the FDA had not yet allowed these ingredients to be used in the United States.

Most concerning, many of the chemicals used in these types of sunscreens may be dangerous to your health. Several of these chemicals have been shown to have estrogenic effects, and many more are suspected as well. Hormone disruption from these chemicals happens because chemical sunscreens are readily absorbed into the skin (that’s how they work) and bloodstream, essentially allowing them access to all parts of our bodies.

Most chemical sunscreens contain, as UVA and UVB blockers, from 2 to 5% of compounds avobenzone, benzophenone, ethylhexyl p-methoxycinnimate, 2-ethylhexyl salicylate, homosalate, octyl methoxycinnamate, oxybenzone (benzophenone-3) as the active ingredients.
  • Benzophenone (and similar compounds) is one of the most powerful free radical generators known. It is used in industrial processes as a free radical generator to initiate chemical reactions. Benzophenone is activated by ultraviolet light energy that breaks benzophenone's double bond to produce two free radical sites. The free radicals then react with other molecules and produce damage to the fats, proteins, and DNA of the cells - the types of damage that produce skin aging and the development of cancer.
  • A study found that mothers with high levels of oxybenzone in their bodies were more likely to give birth to underweight baby girls. (Wolff 2008) 
  • In March 1998, Dr. John Knowland of the University of Oxford reported studies showing that certain sunscreens containing PABA and its derivatives can damage DNA, at least in the test tube experiments. When a chemical sunscreen, Padimate-O, was added to DNA and the mixture exposed to the ultraviolet rays of sunlight, it was found that the sunscreen broke down in sunlight, releasing highly active agents (free radicals) that could damage DNA. It did not block out the UV, but instead absorbed energy. “It became excited and set off a chemical reaction that resulted in the generation of the dangerous free radicals and broken DNA strands that can lead to cancer,” he said and further commented that while it's too early to make blanket recommendations, “I would not use a product containing PABA, Padimate-O or other PABA derivatives.” 
Physical (aka Mineral) sunscreens, which sit as a layer on top of the skin and are not absorbed, are typically made with titanium dioxide and/or zinc oxide. They create a physical barrier that essentially reflects the UV light away from your skin, similar to how a mirror works. When used as an ingredient in sunscreen, zinc oxide sits on the skin’s surface (i.e. is not absorbed into the skin) and blocks both UVA (320–400 nm) and UVB (280–320 nm) rays of ultraviolet light. Because zinc oxide and titanium dioxide are not absorbed into the skin, they are generally non-irritating and non-allergenic.

“Sun Protection Factor” or SPF is commonly used as a little more than a marketing tool on sunscreens. SPF is supposed to be a measure of the effectiveness of the sunscreen in increasing the amount of time you can spend out in the sun before getting a sunburn. However, until recently, this was an unregulated measurement decided on only by the manufacturer of the sunscreen. The SPF measurement is only applied to wavelengths in the UVB, as it is a measure of how long you can be in the sun before getting a sunburn. Because UVA does not cause reddening of the skin (sunburn), it is not measured in the SPF ratings on sunscreens, even though too much UVA has significant risks, ranging from photo-aging of the skin up to cancer.

Choose quality:

EWG recently released its 2011 report on sunscreens and had this to say:
“In the United States, consumer protection has stalled because of the FDA’s 33-year effort to set enforceable guidelines for consumer protection. EWG has found a number of serious problems with existing sunscreens, including overstated claims about their perfomance and inadequate UVA protection. Many of these will be remedied if and when the FDA’s proposed sunscreen rule takes effect. But even after the rule is enacted, gaps will remain. FDA does not consider serious toxicity concerns such as hormone disruption when approving new sun filters. The new rules would also still allow sunscreen makers to use ingredients like vitamin A that can damage the skin in sunlight, and would fail to require makers to measure sunscreen stability despite ample evidence that many products break down quickly in sunlight.” [emphasis ours]
“After reviewing the evidence, EWG determined that mineral sunscreens have the best safety profile of today’s choices. They are stable in sunlight and do not appear to penetrate the skin. They offer UVA protection, which is sorely lacking in most of today’s sunscreen products.”
The choice is clear: mineral sunscreens block out both UVA and UVB radiation well and they do not pose the risks of systemic effects caused by chemical sunscreens. When it comes to effectiveness and safety, mineral sunscreens win on every count.

I think you missed a spot... It's important to get full
coverage when applying sunscreen to prevent damage
to your skin.
What do I do?

Because I hate the feel of sunscreen so much (even the mineral kind), I work really hard to stay covered up when I go out into the sun. I wear a proper sunhat, one that is tested to screen both UVA and UVB radiation. I wear proper sunglasses (UV filter and Polarized). I cover my skin with sun protective clothing if I am faced with being out in the sun for any significant period. Even so, I do have sensitive skin and if I am faced with a long day in the sun (even on a cloudy day), I will add a mineral sunscreen for added protection.

When it comes to applying my sunscreen, I try to follow the recommendations of the National Institute of Health:
“... sunscreen should be applied liberally to exposed sites 15 to 30 minutes before going out into the sun, followed by reapplication of sunscreen to exposed sites 15 to 30 minutes after sun exposure begins. Further reapplication is necessary after vigorous activity that could remove sunscreen, such as swimming, toweling, or excessive sweating and rubbing.”
The most (direct) sunlight exposed areas of the body are most at risk, so that’s where I apply protection first and foremost. Some of the most common areas at risk are the ears, neck, face (especially nose), shoulders, arms, and the back of your hands. Even if you’re in a car and you aren’t under direct sunlight, your arms and hands are likely to still be exposed to UV radiation. In fact, I have added transparent 100% UV protective film to the windows on my car. After adding this UV protection to my car, I found that my hands and forearms were not only better protected from UV light but that my car also stayed much cooler on sunny and hot days.


There are benefits and risks to sunscreens. The closer to the equator you get and the fairer your skin, the greater the need for you to use sunscreen (and/or proper protective sunhats, protective sunglasses, and sun protective covers) regularly and diligently. This is especially true during the highest risk times during mid-day (approximately 10 AM to 4 PM depending on time of the year and latitude).

The safest and most effective sunscreens are mineral based sunscreens. Avoiding chemically based sunscreens is especially important for children and pregnant women as they are at the highest risk for suffering more serious consequences from the hormone disruption effects caused by these sunscreens. Finally, if you live in areas of the world that are far from the equator, or use sunscreen every time you are out in the sun, it is especially important to ensure that you are getting adequate vitamin D supplementation.

For more reading: - Information about the negative effects of chemical sunscreens

Researched and written by Dr. Rebecca Malamed, M.D. with assistance from Mr. Malcolm Potter.

1 comment:

  1. Thank you for your comment. It is much appreciated. Dr. Rebecca


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