The use of suncreams affects vitamin D levels depending on the way they are applied, a new study has suggested.
Suncream prevents the skin from burning and lowers the risk of skin cancer, but it is also said that these creams stop your skin from producing vitamin D, reports dailymail.co.uk.
Antony Young, a professor of experimental photobiology at St John's Institute of Dermatology, King's College London, recruited 79 men and women who were about to go on a week's holiday.
Their vitamin D levels were checked, and they were asked to apply suncream from morning to evening.
It was found that people didn't apply the right amount of sunscream to reap benefits.
"You should use 2 mg of suncream per centimetre of skin, but most people don't use anything like that much. I have calculated that when people apply a factor 30 suncream, the way they put it on means they get the equivalent protection of a factor 4," said Young.
"So we showed one group how to apply it and gave them a tube each day (of SPF 15) with the correct amount for them to apply. The other group were allowed to take their own suncream and apply it as they normally would," he added.
The results showed that even those, who used suncream in abundance, had a considerable increase in their vitamin D levels one week later.
"The group, who applied their own suncream, had an increase in vitamin D levels of 28 nanomoles (nml) per litre, but also had substantial sunburn," said Young, whose study, part-funded by Boots, is due to be published this year.
However, people in the group, who had been taught how to apply suncream, had an increase of 16 nml per litre of blood, but they didn't get any burns.
"That is still a significant rise in vitamin D levels," he said.
Suncreams filter out UVB - the part of the sun's rays that causes sunburn. However, UVB is also what stimulates our bodies to produce vitamin D.
Professor Young believes his results show that some UV will get through the suncream.
Dorothy Bennett, a professor of cellular biology at St George's, University of London, argues that creams with a higher SPF might produce different findings. "However, this does show you can stay safe in the sun and still get enough vitamin D."