Staying protected from sun exposure is more complicated than you may think, discovers Gill South.

I have been slightly alarmed by talk about harmful chemicals in sunscreen after a GP friend of mine said she wasn't putting suntan lotion on her kids any more because of all the harmful things the lotions contained. Her kids have olive skin, but my family are the Celtic types - we can't get away with this.

I'll never forget a really bad burn when I was 17 - I thought it was a smart idea to just lie on my back on a sunny day out at Piha. I think I got into a book and just didn't remember to rotate like a rotisserie chicken. I remember waking up in the morning to blisters on my chest, sobbing in pain.

I've had freckles there ever since to remind me of my stupidity.

Dr Sharad Paul, the skin cancer expert, who runs the Skin Surgery Clinic in Blockhouse Bay and is senior lecturer in skin cancer at the School of Medicine, University of Queensland, tells me in New Zealand we have a large Celtic population who migrated to a place where they were not designed to live.


Dr Paul says the labelling on many sunscreens is confusing. A lot of people mistakenly believe that an SPF 30 rating gives twice the sun protection of an SPF 15. In fact, many studies have shown that SPF 15 sunscreens filter out 93 per cent of UVB rays, while SPF 30 protects against 97 per cent - so the actual difference is minimal.

Most of the alarmist talk on the web is the use of nanoparticles in some sunscreens. As zinc oxide has a whitish appearance, many products use nanoparticles of zinc oxide to avoid such a look or to make the zinc "invisible".

Such small particles can penetrate individual cells and the long term effects are unknown, says Paul. His personal view is to avoid nanoparticles.

I tell Dr Paul I use Invisible Zinc which I came across in Australia but which sells here. The manufacturers use zinc oxide which is a good broad-spectrum sunscreen and is here "micronised" to a size larger than a nanoparticle, he says.

When I asked Dr Elizabeth Baird from Remuera Dermatology which sunscreen she would recommend, she snarled, "All of them!"

She sees too many skin cancer patients. She likes a 30+ broad-spectrum sunblock.

Dr Baird told me it is believed the average person receives 50 per cent of their cumulative sun exposure by the time they are 18. So I just snuck in there with my Piha pasting.

I remember her telling me she wouldn't let her son play cricket because of the sun exposure. I have two aspiring Black Caps. This year they are definitely wearing sunglasses and hats, not caps, and lotion will be reapplied more.


The Cancer Society, whose sunscreen does not contain any nanoparticles in their formulations, tells me UV levels are high in NZ from September until April so we should be applying during this period. A usual application should include at least teaspoon to each arm, and to the face, including the ears and neck; and at least a teaspoon to each leg, the front of body, and the back of body. That's 35ml in all. Always reapply sunscreen every two hours when you are outdoors. And apply sunscreen 15 minutes before sun exposure to allow time for it to dry and be absorbed into the skin.

They also warn that the big thing with suncreams is they have to be scientifically proven - you can't have Sophie from Kerikeri making her own thing without standardised testing. When choosing your sunscreen you need to make sure the formula is actually going to work by checking the testing that has been applied to the product. At the Cancer Society they use the Australian standards to make sure their products retain the stated SPF 30+ after two hours in the water.

They recommend that you always look for at least an SPF 30+. The SPF shows that the sunscreen has been measured against the standards and will protect you if applied according to instructions.

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Next week:

I've always been intrigued by what the state of my nails tells me about my health. I am booked in to see naturopath Hope Pearce at Purely Health in Mt Eden for an examination.