Advice Column, Health

Do Sunscreens Really Prevent Skin Cancers?

  • Lynne Brown
  • Category Advice Column, Health

Not long now and you may be heading off to your summer holiday at the sea, which brings me to the topic of sunscreens.  Being a sun-worshipper myself, with a strong belief in the therapeutic properties of sunlight, I will never be convinced that it is not good to get a healthy dose of the sun every day. It is essential for health, for life and for happy moods!

Yes, too much sunlight can cause sunburn, and sunburn is a risk factor for skin cancer. But then one would assume that since sunscreens help prevent sunburn, they should reduce the risk of skin cancer too, right? Yet no study on melanoma or basal or squamous cell carcinoma has shown convincingly that sunscreens prevent the formation of new skin cancers or reduce the risk of melanoma. A few theories as to why this is so, have been put  forward, which include:

  • The sorts of people who use sunscreen (e.g. fair-skinned) are generally at enhanced risk of skin cancer to begin with.
  • Use of sunscreen makes people think they are not getting burned so they stay in the sun longer
  • Sunscreen blocks out the UVB needed for Vitamin D production, but allows in the UVA, considered the melanoma culprit.
  • Sunscreen blocks the manufacture of vitamin D which is linked to cancer-protective effects.
  • The potentially carcinogenic effect of certain chemicals used in sunscreens

More evidence pointing to sunscreens being the problem rather than the solution are these three astounding facts:

  • Melanomas most commonly occur in countries that are less sun-exposed
  • Are more common in indoor workers than outdoor workers and
  • Most melanomas do not occur in typically sun-exposed parts of the body.

I “pale” at the potential consequences of the current “keep your children out of the sun or slathered from top to toe in sunscreen” trend on the long term health of our children. Just to give you an example of how powerful sunscreens are, apparently a sunscreen with an SPF of 8 can reduce your ability to make vitamin D in your skin by more than 95%. Low vitamin D levels can cause bone disease and is linked with enhanced risk of cardiovascular disease and, yes you have guessed it, several forms of cancers. More than 200 epidemiological studies have confirmed that the anti-sun propaganda may well have led to a chronic deficiency of vitamin D, which may be contributing to increasing cancer incidence, including melanoma.

You will be amazed to know that even in South Africa average serum vitamin D levels are dropping to levels insufficient to protect us against cancer and other degenerative diseases. Furthermore the recommendation that we should avoid the midday sun and rather get our sun exposure before 10am and after 3pm has also been reversed.  To maximize your vitamin D production and minimize your risk of malignant melanoma, the middle of the day (roughly between 10:00 a.m. and 1:00 p.m.) is the best and safest time. During this time you need the shortest exposure time to produce vitamin D because the protective UVB rays are most intense at this time- approx 15 minutes for light skins but longer for dark skinned people. As the sun goes down, the UVB is filtered out much more than the dangerous UVA.

So get outdoors in the sun during the peak hours but DO NOT get burnt. Expose as much of your skin as possible till a slight pink colour says its time to cover up again. If you need to be in the sun for long periods cover up with a T-shirt and hat. Apply the same rules to your children. It is also a good idea to have your vitamin D levels checked by means of a simple blood test and if your levels are below 50ng/mL, and being in sunlight often enough is not an option for you, then it would be wise to take an oral vitamin D3 (not D2) supplement. Look for cholecalciferol and depending on how low your level was, take between 1000 and 5000IU daily.

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