On the sun ...

lYesterday was the first really summer-like day of the year ... and while my family and I reveled in the warmth and the sun, it prompted discussions of sunscreens.  My kids were asking questions about the chemicals in the sunscreens, exploring the risks of the gunk vs. the risks of sun damage - they are the children of a naturopathic doctor afterall ... they know to inquire about such things!  So here are some thoughts and resources:

Sun exposure is clearly linked to the risk of skin cancer, which is the most common type of cancer in Canada.  While all types of skin cancer are treatable, they can also be aggressive and deadly.  Malignant melanoma is one of the most aggressive types of cancer.  Here is more info on melanoma; bottom line:  talk to your doctor if you have any new skin spots.  The earlier skin cancer is identified, the better the prognosis.

Sun exposure is also beneficial for a couple of reasons.  Vitamin D is made in the body in response to sun exposure.  Canadians are notoriously deficient in vitamin D due to lack of sun exposure during long stretches of shorter, colder days.  This is possibly complicated by active efforts to reduce sun exposure, since efforts to reduce UV exposure may contribute to vitamin D deficiencies (though this is controversial); however, some studies have demonstrated that Canadians are spending more time in the sun, not less, and not necessarily with a corresponding increase in sunscreen use.  Ironically, vitamin D deficiency itself is a risk factor for malignant melanoma; it has thus been suggested that inadequate exposure to the sun may also be a risk factor for skin cancer.  It's hard to elucidate exactly what the ideal amount of exposure might be, since individuals have unique susceptibilities to both sun damage and vitamin D deficiency based on pigmentation, age, latitude and genetic variations.  Vitamin D needs can also be met through food and supplementation.

Sunlight is also important for regulation of both mood and circadian rhythms.  This may not require direct exposure of the skin to UV radiation, although some studies have acknowledged the presence of a circadian clock in the skin, a fascinating mechanism by which organisms (including humans) may regulate behaviour and immune function.  This neat study convincingly shows that an indoor lifestyle disrupts our natural circadian pathways, with implications on cognitive function and mental health; more exposure to natural (vs. artificial) light may be a more appropriate approach to circadian regulation.

Acknowledging that some sun exposure has benefit, the connection of excessive exposure - particularly the kind that results in burns - with skin cancer should prompt caution.  Kids are particularly vulnerable, so caregivers should both be vigilant about protecting them AND setting a good example of safe sun practices themselves (not cool to wrestle sunscreen on your child if you're not wearing it too!).  There are a variety of excellent ways to minimize the risk of skin damage from UV radiation, including avoiding midday sun, covering up with long sleeves, hats, sunglasses and umbrellas, and wearing sunscreen!

But what about those chemicals??  The Canadian Cancer Society argues that chemicals in sunscreens are safe, and they very well may be.  But perhaps there are some options that are better than others?  A quick guide of things to consider:

- Oxybenzone: this is a common active ingredient in sunscreens; the concern with this one is allergy or immunosensitivity; best to avoid if an alternative is available
- Octinoxate:  another common UV-filter with concern of toxicity; this one more concerning for its potential hormone disruption
- Fragrance:  while not specific to sunscreens, fragrance is a catch-all term for any artificial scent added to personal care products; because there is no requirement to be more precise in labeling, a consumer has no way of knowing if the chemicals used are safe or not; best to always avoid

Mineral sunscreens work differently than chemical ones.  Zinc oxide and titanium dioxide sit on the surface of the skin and reflect radiation off, rather than being absorbed the way chemical filters are.  It means that sunscreens containing these ingredients are thick and white, and not always appreciated by the wearer, to which my kids can attest!  One option is to look for sunscreens that contain a blend of chemical and mineral ingredients, and that do not use oxybenzone or octinoxate.  The Environmental Working Group has a very comprehensive review of options if you're looking for more guidance!

Be careful too of SPF claims - regardless of how high your SPF is, if you're using sunscreen, apply a lot and apply often ... there is some suggestion that folks who wear sunscreen may actually be at a higher risk of skin cancer ... not because the sunscreen causes cancer, but because it is applied incorrectly and causes a false sense of security (resulting in more time spent in the sun inadequately protected).

One more thing to ponder ... UV exposure causes skin cancer by damaging the genetic material of skin cells.  This occurs in part due to the generation of free radicals and reactive oxygen species.  Our cells have mechanisms to neutralize these free radicals before they cause irreparable damage, particularly when we provide the right ingredients for these mechanisms in the form of nutritional antioxidants!  A diet rich in antioxidants, including brightly coloured fruits and veggies, abundant herbs and spices, and flavonoid-rich green tea - even dark chocolate! - may protect our skin from damage due to UV radiation (along with other lifestyle-induced cancer promoters).  So in addition to moderate sun exposure and thoughtful selection and use of sunscreens, here is even more rationale for eating a great diet!

Have fun in the sun!  

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