Dr Sandi Nye ‘Wear sunscreen. If I could offer you only one tip for the future, sunscreen would be it.’ ~ Mary Schmich, 19971
SUNSCREEN PROTECTION FACTORS
Zealous advertisers advocate sunscreen products with sun protection factors (SPFs) ranging from 15 to 100+. But how much of this is scientifically validated, and how much is spin-doctoring taking advantage of fearful and gullible consumers? Is an SPF of 100 really twice as good as one of 50, or even 30 or 15 for that matter? The short answer is no. The numbers do not compute that simply, as we will see.
SPF refers to a sunscreen’s ability to block ultraviolet B (UVB) rays, as well as to how long it would take someone to burn in the sun with and without sun protection. Some sunscreens, however, only protect us from UVB rays – those that cause superficial skin burning. They don’t block ultraviolet A (UVA) rays – the radiation that suppresses the immune system, harms connective tissue, causes deeper skin damage and elevates the risk of melanoma. In general, both UVB and UVA rays contribute to skin cancer risk.
Products with an SPF of 15 block about 94% of UVB rays, whereas those with SPFs of 30 and 45 block about 97% and 98%, respectively. Although products with higher numbers claim otherwise, there are as yet no sunscreens that offer 100% protection. A leading sunscreen manufacturer issued the following statement: ‘While the difference in the percentage of ultraviolet radiation blocked between an SPF 55 and SPF 100+ may be slightly less than 1%, applying an SPF 100 may lead to much less cumulative sun damage over a lifetime.’ Is this sufficient evidence for us to buy into the hype, and do we really want or need 100% UV protection for optimal health? Just because we’re led to believe that we’re protected by 50+ and 100+ SPF products, does suppressing sunburn, with the resulting temptation to sizzle in the sun for too long, justify our faith in sunscreens? Or has all that sunshine fried our brains along with our hides? We have to stop subjecting ourselves to excessive and intense sun exposure, just because sunscreens allow us to stay in the sun longer than is wise or sane – especially if we want to decrease our risk of developing melanoma, or ending up looking like a shrivelled-up brown prune.
Can we maximise sun safety without compromising our vitamin D production? The simple answer is yes, we can enjoy the sunshine sensibly. More and more people are being diagnosed with low, borderline or serious vitamin D deficiency these days. Is this a result of limited sun exposure, or over-use of sunscreens? Our bodies need this fat-soluble vitamin for many critical functions, and there are sensible, practical and nutritional ways to enhance our sun resistance or susceptibility. Many of these allow for the benefits of judicious sun exposure while minimising the risk of burning, e.g. eating sun-wise foods, wearing sun-protective clothing and, staying out of the direct sun between 11 a.m. and 3 p.m. (remember the song ‘Mad dogs and Englishmen go out in the midday sun’?).
It appears that, to be of benefit, sunscreens need to be applied in sufficient quantity, and relatively frequently, because when incorrectly applied they can cause more free-radical damage than UV rays on bare skin. Their function, however, is sun protection, not free-radical suppression, even though many of the common sunscreen ingredients do generate these rogue molecules that damage DNA and skin cells. So, how much and how often? How much depends on where and on whom it is being applied. For an adult, the recommendation is 5 millilitres (1 tsp) per body part, i.e. two arms, two legs, front of body, back of body, face, neck and ears, which comes to 35 ml (7 tsp) for each full-body application. Depending on the size of the child, about half the adult amount is recommended, i.e. 2.5 ml (1/2 tsp) per body region or about 18 ml in total.
How often? That depends on the SPF, and how the sun affects you. For example, assuming it takes you 15 minutes to get sunburned, and you apply a sunscreen with an SPF of 15, you multiply the two numbers to work out your sunburn risk factor – 225 minutes (3 hours and 45 minutes) in this instance. However, along with issues like sweating, humidity, contact with water, and time of day, the mathematics change when one gets to SPFs of 30 or higher – an SPF of 50 does not mean that you only need to re-apply sunscreen every 12 hours! The general recommendation is to re-apply at least every 2 hours, or more frequently when swimming or sweating.
CHOOSING A SUNSCREEN
Many people want to use sunscreens, but are put off by the high cost of some of these products. Others are concerned about natural versus unnatural (chemical) ingredients. What to use – and what to avoid? Organic and mineral-based sunscreens (containing nano-particles of zinc and titanium) are your best choices. Products to avoid include those considered to be hormone disruptors (containing oxybenzone), those that form free radicals in the presence of sunlight and may exacerbate skin cancer risk (containing retinyl palmitate/retinol/vitamin A), and those that become harmful when degraded by UV light. In general, it appears that ‘chemical’ sunscreens pose greater toxicity risk than ‘mineral’ sunscreens, since they are less stable, penetrate the skin, and contain ingredients that are potential hormone disruptors. Modern mineral sunscreens are not thought to penetrate the skin, are stable in sunlight, and offer additional UVA protection.
In conclusion – which sunscreen should you choose for you and your family? Only you can decide, and I hope the information provided will help you make an informed decision. And don’t forget – a personal umbrella, like a hat and gloves, can be wildly stylish!