Sunscreens have never been proven to protect against skin cancer or immune
suppression. The BC Atmosphere Caucus is very concerned about this fact,
and is urging the public to cover up instead of using sunscreen.
The following excerpt has been taken from Mother Jones Magazine, May 1993:
***** DO SUN SCREENS PROMOTE CANCER? *****
By Michael Castleman
Most sunscreens block about 5 percent of ultra violet radiation
--the UVB rays that cause skin to burn. The other 95 percent of
the UV spectrum, UVA, has long been thought to play a minor role
in sunburn, so sunscreens block only a small portion of it. But
studies have shown that UVA may play an important role in skin
cancer. UVA radiation penetrates more deeply into the skin than
UVB, down to the melanocytes, the cells that turn into cancerous
melanoma.
Scientists have yet to identify exactly what corrupts healthy
melanocytes, largely because there is no animal model for
melanoma. But mice develop nonmelanoma skin cancers under UV
light.
Proponents of the sun burn theory are quick to point to a
Danish study in which sun screen was shown to delay (but not
completely prevent) the development of squamous cell tumors
in mice exposed to artificial sunlight. The higher the sun
screen's sun protection factor (SPF), the longer it took the
mice to develop tumors. To date, this is the closest scientists
have come to establishing the preventive value of sunscreens.
However, another study at the same lab should give sun screen
advocates pause. In this experiment, mice exposed to artificial
sunlight developed a small number of squamous cell tumors. But
ones exposed to artificial sunlight followed by additional UVA
developed more than twice as many tumors.
Not only does this study suggest that UVA may play a role in
skin cancer, it also points to the particular danger of sunlight
followed by UVA alone--a cycle similar to that which occurs when
people use sunscreen. They hit the beach, playground, or ball
field and remove some clothing, exposing themselves to full
spectrum sunlight. Then they apply sunscreen, blocking UVB,
but continuing their exposure to UVA. As the sunscreen wears off,
they're again exposed to full sun. After reapplying sunscreen,
they get additional UVA--and possibly cancer.
Of course, mice are not human beings, and squamous cell cancers
are not melanoma, so either study (or both) may mean nothing.
But melanoma experts trumpet the implications of the first
study, that sunscreens help prevent skin cancer, while ignoring
those of the second, that sunscreen use fosters a cancer-promoting
pattern of UV exposure.
Unfortunately, there is more disturbing news about sunscreen:
by impairing the body's production of vitamin D, it may also
remove a defense against cancer. According to studies,
vitamin D has a hormone-like effect that interferes with the
growth of several tumors, including those associated with
melanoma and colon and breast cancers. Although we get small
amounts of the vitamin from milk and cold-water fish, most of
our bodies' supply is produced when skin is exposed to UVB.
By blocking UVB, sunscreens interfere with vitamin D synthesis.
A recent study shows that habitual sunscreen users have unusually
low vitamin D levels--sometimes low enough that researchers call
them "deficient."
To prevent malignant melanoma, start by using common sense instead
of just sunscreens. First, assess your risk. Risk factors include:
fair skin;blonde, red, or light brown hair; blue or green eyes;
a family history of melanoma; an indoor occupation; outdoor
leisure activities; numerous moles; freckling on the upper back;
a tendency to sunburn easily and tan poorly; and actinic keratoses,
rough, red, sun induced bumps which sometimes develop on fair skin.
The more risk factors that you have, the more concerned you need
to be. Any skin colour can develop melanoma, but for those without
risk factors the danger is slight.
It is agreed that the best way to prevent harm from sunlight--burning,
wrinkling, and all forms of skin cancer--is to avoid direct sun
between 10 a.m. and 3 p.m. Just take reasonable precautions: Don't
sunbathe. If you love the beach, invest in an umbrella. Don't
patronize tanning salons. In summer, adjust your schedule to engage
in outdoor activities in the early morning or late afternoon. When
out on summer days, wear a hat, sunglasses, and lightweight,
long-limbed clothing.
Remember, there is no such thing as a "healthy tan," so don't go
looking for one. Even if you take all the precautions listed above,
you'll still acquire some colour in the summer without significantly
raising your melanoma risk.
The following excerpt is taken from Monday Magazine May 20-26,1993:
***** SUNSCREEN SMOKESCREEN *****
By James McKinnon
"The next time you buy a sunscreen, look up the company's phone number,
give them a call, and ask whether their product will protect you from
skin cancer.
The answer, invariably, will be complex and long-winded. The truth will
be "No".
Sunscreens, as is usually carefully stated on the bottle, protect
from "the sun's burning rays" -- nothing more.
About five percent of the ultra violet (UV) spectrum is blocked by
sunscreen -- the UVB radiation that burns our skin.
The other 95% of the spectrum -- UVA rays -- bypass sunblock and
penetrate deeply into the skin, where they may cause cancer. In
fact, no one is sure which type of UV radiation causes skin cancer,
or even if the rays are the cause at all.
The problem with sunscreens is not that they claim to prevent cancer,
but that many people assume if their skin isn't burning they aren't
at risk for skin cancer. With sun block on, they stay out longer in
the sun, playing with a deadly scientific uncertainty.
Ozone researcher Wayne Evans of Trent University said children are
particularly at risk, and simply should not be exposed to this
summers sun without proper protective clothing.
Also, evidence is growing to suggest sunscreens do not prevent
damage by UV rays to the immune system, opening the body to a greater
risk of diseases.
According to Eric Taylor, a Scout leader and Environment Canada
climatologist, sun protection should be three-tiered:
1. Avoid long sun exposure between peak UV hours of 10am to 3pm.
2. Wear a wide-brimmed hat,sun glasses, and long shirts and pants during
any long exposure.
3. Wear sun block on difficult to protect area's (like the nose), or
when long exposures are unavoidable, such as for outside workers.
The BCAC has asked many sun screen companies to provide us with scientific
data on the effectiveness of their sun screen. Currently, not one of our
requests has been answered or even recognized.
The following excerpt has been taken from Mother Jones Magazine May, 1993.
***** How to Spot Melanoma in Moles *****
By Michael Castleman
Few people understand how life-saving early melanoma detection can be.
Seventy percent of melanoma tumors develop from pre-existing moles.
So examine your moles regularly--or have someone else do it--and know
the ABCD's of melanoma detection.
* Asymmetry: Most normal moles are round and symmetrical.
Melanomas are oddly shaped and asymmetrical.
* Border: Most normal moles have smooth edges. Melanomas
often have notched or scalloped edges.
* Colour: Most normal moles are a single shade of brown.
Melanomas are black, blue, pink, and multicolored.
* Diameter: Most normal moles are less than one-quarter
inch in diameter. Early melanomas often grow outward and
become larger.
Even before melanoma moles undergo visual changes, they often itch.
If one of your moles starts to itch, or begins to discharge fluid,
or if you become nervous about a mole for any reason, ask your
doctor for a referral to a dermatologist. If you have significant
melanoma risk factors, see a dermatologist annually.