Slap on your sun-greens

Kelly Curtis. Photo / Herald on Sunday

Sun lovers may be covering themselves in broccoli juice in the future as scientists devise new ways to keep skin cancer at bay.

Broccoli contains sulforaphane, an antioxidant, which helps stop sunburn and tumour development.

Scientists in the United States have been testing broccoli extract on human volunteers and mice, which showed their skin was protected against sunburn.

And here in New Zealand, there is a school of thought that extract from totara and manuka trees could act in a similar way to broccoli.

The research comes amid concerns from scientists about the chemicals used in conventional sunscreens and the potential dangers they pose to the body.

Cancer Society chief executive Dalton Kelly said he hadn't heard of the broccoli research, but new products were constantly being tested.

"I hope something develops from it. There are new and exciting things being tried and tested all the time," he said. "Improvements do come, and in the meantime we work with the best that we've got with the research of the time."

Sunscreen is a multi-million dollar business and there is a huge range on the market. New Zealand has the highest rate of skin cancer in the world. Melanoma claims the lives of 300 New Zealanders each year and a further 2000 new cases are diagnosed each year.

Ten years ago, New Scientist magazine published an article "The Sinister Side of Sunscreen" which explored research indicating active ingredients in sunscreen release potentially harmful free radicals into the body when they react with sunlight.

This year, a study published in the International Journal of Endocrinology and Metabolism also revealed test rats exposed to sunscreen ingredients suffered hormonal imbalances.

These chemicals, octyl-methoxycinnamate and butyl methoxydibenzoylmethane, are found in most products available in New Zealand.

New generation mineral sunscreens use zinc and titanium oxide to block and deflect the sun's rays rather than chemicals that act as UV "absorbers".

Skin care specialist Kelly Curtis said mineral products had developed significantly since the "peanut butter-like" zinc available 30 years ago.

"People see that it's got titanium oxide or zinc and it brings back memories of that thick, coloured stuff from the 1980s. But the products really have improved and by using physical blockers rather than chemical sunscreens, you are minimising the amount of chemicals going into your body."

The Cancer Society's Mineral Zinc SPF30 Sunscreen ($27/150g) and Environ RAD SPF15 ($51/75g) are among the products appearing on the market to meet the demand for chemical-free products.

Kelly said any product must be applied thoroughly and regularly and Dr Joanne Harvey, a chemical scientist at Victoria University, also said no matter what strength sunscreen was being used, it must be applied liberally.

Kelly is concerned people who buy new products with a high SPF rating may fall into a false sense of security.

"The problem is, people put it on and think they are set for the day," Kelly said. "They treat it like a shield of armour. But they still need to be re-applying it regularly, especially if they go for a swim."

Kelly also said it was important to check a sunscreen was approved by the Australian Therapeutic Goods Administration, as many products were not tested to match up to New Zealand conditions.

"A lot are made in Taiwan and Thailand and, while they are perfectly legal, they haven't undergone the same level of testing. They aren't necessarily broad-spectrum protection and the SPF is measured before it is immersed in water, for example."

Even the perfect sunscreen cannot overcome human error. Said Harvey:

"When we layer on sunscreen, we make mistakes. People will forget to do their right arm or their top will shift. The best protection is not going out into the sun, at least in the middle of the day."

Tiny freckle to major health scare

Beauty therapist Kelly Curtis grew up in Hawkes Bay during a time when no-one knew about the dangers of the sun.

"We were told to go and play outside, we'd be out in the pool all day. There might have been a token bottle of SPF8 around but we didn't really use it."

Then last year, the 36-year-old began to notice a freckle on her forehead was changing. "It was growing and changing shape. My GP said it was nothing to worry about, that he could take it out if I really wanted to but I didn't need too," she said.

"It continued to change but I was running my own business and that's where all my time and focus was."

By Christmas time the freckle had become raised, large and dark. Curtis went back to the doctor.

"He took one look at it and said 'We have to get this out right away'. It was a stage two melanoma."

Melanoma is a vicious form of skin cancer that spreads quickly so Curtis went through a series of medical tests - which revealed a tumour the size of a tennis ball in her stomach.

"It turns out it was unrelated to the melanoma, but it was really lucky they found it."