A US doctor has claimed warnings about getting skin cancer from the sun may prevent healthy levels of exposure.
Sunbathing is linked to skin cancer
Dr Michael Holick says we are missing out on essential vitamin D by staying out of the sun - and that causes thousands of deaths each year.
However, his controversial views have cost him his job as Professor of Dermatology at the Boston University School of Medicine.
And UK experts have warned excessive sun exposure is dangerous.
Dr Holick told the BBC Today programme: "What I am suggesting is sensible sun exposure. We are talking probably about no more than maybe three to five minutes to your hands, face and arms two to three times a week.
"People don't realise that 90% - 95% of your vitamin D requirement comes from exposure from sunlight, and if you always wear sun block and never have direct sun exposure you will become vitamin D deficient, and at high risk of developing many serious chronic diseases."
Dr John Toy who's medical director of Cancer Research UK said excessive exposure to sunlight was linked to skin cancer.
He said rates of the most serious kind of skin cancer, malignant melanoma, had risen sharply in recent years.
"We don't suggest that people lock themselves away in a darkened cellar.
"What we are saying is don't go out into the midday sun, do wear a hat, do wear a t-shirt, do protect young people particularly, because their skin is not so strong, avoid at all costs sunburn, and where necessary put on sun factor cream.
"In casual exposure to the sun you will see sufficient to get your vitamin D."
Dr Toy also stressed that as yet there was no definitive proof about some of the health benefits made for vitamin D, which includes claims that it might reduce the risk of some forms of cancer.
"My concern is that the mixed messages will produce confusion in people's minds.
"At the moment the evidence states categorically that there is a link between sun exposure and skin cancer.
"The evidence does not state categorically that vitamin D improves the chances of not developing cancer."