Controversial new research argues that we need sunshine to boost our vitamin D intake. So have we all been wasting our time lying in the shade?Nadine O'Regan reports

First comes the Irish sun, then come the Irish sunbathers. Across the front pages of the newspapers they will soon sprawl, pink-skinned and grinning, soaking up the sun.

The cheery mood of these summer photographs contrasts with the dark tone of the inevitable skin cancer articles on the inside pages.

According to the most recent figures from the National Cancer Registry, there were 5,596 new cases of skin cancer in Ireland in 2001.

Next Monday, the Irish Cancer Society will launch another SunSmart campaign to remind the public of the importance of covering up, using sunscreen and staying in the shade between 11am and 3pm, when the sun is strongest.

But this summer its task will be harder - and more controversial - than before. Where once the message was clear, now it has become confused.

Recent research suggests that staying in the shade is bad for your health, leaving you deficient in vitamin D, the production of which is triggered by the sun.

"A balance is required between avoiding an increase in the risk of skin cancer and achieving enough ultraviolet radiation exposure to achieve adequate vitamin D levels," warned the research from the Medical Journal of Australia.

While rickets is the disease most commonly associated with a lack of vitamin D, some authors and scientists believe that the repercussions of vitamin D deficiency are far more serious and wide-ranging than previously imagined.

"Evidence shows that insufficient vitamin D is closely associated with, and almost certainly is a cause of, chronic diseases including schizophrenia, multiple sclerosis, diabetes, polycystic ovary disease and 16 different types of cancer," says Oliver Gillie, author of the report Sunlight Robbery. "Sunlight does you good and we need to be exposed to it."

Recent lung-surgery research would seem to support Gillie's position. In a study, people who underwent surgery for early-stage lung cancer were found to fare better if the operation took place during a sunny time of year or if they had a high intake of vitamin D beforehand.

"This study showed a pretty strong relationship between vitamin D intake or season, and disease-free and overall survival," said Dr David Christiani, a professor of epidemiology at the Harvard school of public health.

The implications of studies like these are troubling. Have we spent years avoiding the sun only to have put ourselves at risk of attracting terrible diseases? Gillie believes the answer is yes.

"The strength of this (judgment) comes from the fact that all these different sources of scientific information all support each other and are consistent with each other," he says. "Dermatologists have got a lot of face to lose on this. They've been telling us for years how bad sun exposure is and they aren't willing to concede anything."

But dermatologists contend that they have a very good reason not to concede anything - namely, that the new body of vitamin D research is neither large nor compelling enough to overturn their previous findings on the sun.

"We have quite a lot of studies which show that if you're wearing a sunscreen all the time, you don't appear to become vitamin D deficient," says Dr Gillian Murphy, consultant dermatologist at Beaumont Hospital, Dublin. "Ninety per cent of skin cancers are caused by the sun. You cannot argue with that, it's just true.

"The Western diet is well supplemented, so to see vitamin D deficiency in Ireland nowadays is unusual. You don't need to sunbathe for vitamin D. You get it in your milk," she says.

But other authorities, Gillie among them, doubt that diet alone provides the body with sufficient quantities of vitamin D.

There is even less agreement on the research linking sun exposure to the reduction in incidence of diseases such as multiple sclerosis.

"Some studies have been published that suggest possible beneficial effects of sun exposure in the prevention or improvement in outcome of a number of diseases," the Medical Journal of Australia noted. "[ But] there is insufficient evidence for any definitive action to be taken on these findings or make any recommendations, as more research is needed."

Proposals have been made in Ireland to study the vitamin D issue. Investigations in numerous countries around the world, meanwhile, are already underway.

"In Finland, they're measuring vitamin D levels in the winter and the summer to see if people are deficient," says Dr Murphy. "The current medical opinion is that we should investigate more to make certain there isn't something going on that we haven't hitherto understood."

Many in the tanning industry aren't waiting around for the fruits of such investigations, however. They have leapt merrily onto the vitamin D bandwagon, concluding that if natural sunlight is good for you, then so too is artificial ultraviolet light.

But there appears to be no evidence to support this assertion. A wealth of research, meanwhile, weighs heavily against the use of sunbeds.

Women who visited tanning salons once or more per month increased their chances of developing melanoma, the most serious form of skin cancer, by 55 per cent, according to a study published in the Journal of the National Cancer Institute in America.

A statistic like this one, frightening though it is, hasn't stopped an estimated 185,000 people in Ireland from visiting tanning salons.

"People sometimes do not want to change," says Anita Murphy, assistant health promotion officer at the Irish Cancer Society. "Everyone likes to look their best and everyone still thinks that having a tan makes you look healthy. "But sunbeds can emit levels of ultraviolet radiation that are up to five times as strong as the midday sun, so that increases the risk of skin cancer considerably."

Skin cancer is probably not what most people are thinking of when they pop down to their local tanning salon. It appears they're not encouraged to reflect on it either.

In the 2004 survey carried out by the Irish Cancer Society, an alarming 18 per cent of venues showed no guidelines for use whatsoever.

"The industry needs legislation and stricter guidelines," says Murphy. "A big thing at the moment is kids with confirmations and communions. In the survey, one in 20 were under 15 when they first used a sunbed.

"You receive the most sun exposure before you're 18. When you put children on sunbeds, you increase their risk of getting skin cancer even more."

So what should we do to keep our children and ourselves healthy? Should we sprawl in the midday sun, or stay indoors on even the cloudiest of days?

"I would advise people to sunbathe to get their vitamin D, but cautiously so they don't burn," says Gillie. "When your skin gets a feeling of tightness, or you get too hot, you should go into the shade. People with our kind of skin also have to be very careful when going on Mediterranean holidays, because the sun is so much brighter."

Dr Murphy maintains there is no need to push Irish people into the sunlight because we already manage, whether by accident or design, to soak up plenty of it.

"Everybody gets a little bit of sun, whether they like it or not," she says. "It is physically impossible to protect people. At the end of the day, less is better."

In other words: don't ditch the sunhat and sunscreen. The old order might have lost a battle or two in recent times, but their war against the sun is far from over.

For the moment, at least, it is still more enemy than friend.

For further information on skin cancer prevention or on a diagnosis of skin cancer, contact the Irish Cancer Society National Cancer Helpline on Freefone 1800 200 700 (weekdays 9am-5pm).

Myth and reality

Myth: You can't get burnt on a cloudy day.

Reality: "80-85 per cent of solar ultraviolet radiation can pass through cloud," according to the Irish Cancer Society. "Haze in the atmosphere can even increase your ultraviolet radiation exposure."

Myth: You cannot get sunburnt through the glass of a car window

Reality: "Glass reduces some of the transmission of ultraviolet radiation; however it is still possible to get sunburnt," according to the Irish Cancer Society,

Myth: Wearing sunscreen means that it's safe to stay out in the sun for longer.

Reality: "Sunscreens should not be used to stay out in the sun longer. They should be used with other protective measures to increase protection during unavoidable exposure," according to the Irish Cancer Society.

Myth: Using fake tan will protect you from the sun.

Reality: "A fake tan cream temporarily stains the skin," says the Irish Cancer Society. "There is no improvement in your body's ability to protect itself in the sun."

Tanning without sunning

Sunbeds: "When sunbeds were first invented, people thought they were harmless," says Dr Gillian Murphy, consultant dermatologist at Beaumont Hospital, Dublin. "But all the investigations have shown that (the ultraviolet rays they emit) can also cause skin cancer and damage your skin. I can't see a single reason for anybody to use a sunbed."

Fake tan: There are no known dangers with fake-tan products, but they can cause allergic reactions in some people. "Fake tan is just a stain on the surface of your skin," says Dr Murphy. "It's an oxidation reaction. It is harmless apart from (the possibility of) allergy - which would be to the actual fragrance in it rather than the stuff itself."