Following restrictive sun exposure advice in countries with low solar intensity like Canada might in fact be harmful to your health, says the co-author of a new study on sunlight and vitamin D.
The recently published study Sunlight and Vitamin D: Necessary for Public Health by Carole Baggerly and several academic researchers, examines how organizations such as World Health Organization's International Agency for Research on Cancer and the U.S. Surgeon General call for sun avoidance, but ignore the fact that cutting out sunshine will reduce vitamin D, an essential vitamin for bone health, and create probable harm for the general population.
"Humans have adapted to sun exposure over many thousands of years and derive numerous physiological benefits from UV exposure, in addition to vitamin D," said Baggerly, executive director of GrassrootsHealth and breast cancer survivor. "These benefits are in addition to those derived from vitamin D alone and cannot be replaced by vitamin D supplements and therefore sun avoidance being recommended by the US Surgeon General, the Canadian Cancer Society, the Canadian Dermatology Association and others, is unnecessarily putting Canadians at risk."
Vitamin D is an essential vitamin that enables calcium absorption and is critical for good bone health. Low levels are linked to bone conditions such as rickets in children and osteomalacia and osteoporosis in adults.
In Canada, vitamin D from sunlight can only be synthesized in the skin during the spring, summer and fall months, around midday, from 10 a.m. – 2 p.m., when the UV index is above three and your shadow is shorter than your height.
Statistics Canada reports that 12 million Canadians, or 35% of the population, have insufficient vitamin D levels, including 10% who are severely deficient, which sets them up for higher disease risk.
According to Dr. Reinhold Vieth, Scientific Advisor for the Canadian Vitamin D Consensus and professor at the University of Toronto in the Department of Laboratory Medicine and Pathobiology, "If organizations warn people to stay out of the sun, then they should also let people know that they will not be producing vitamin D. Both the risks and benefits of UV exposure need to be addressed in the best interest of health. Unfortunately, the message Canadians keep hearing lately is that there is no benefit to being in the sun. The paper by Baggerly et al presents a clear case that good overall health does correlate with spending time in the sun."
A group comprised of the Multiple Sclerosis Society of Canada, Vitamin D Society and Pure North S'Energy Foundation, have endorsed a draft Canadian Vitamin D Consensus which recommends that Canadians enjoying the sun safely, while taking care not to burn, can acquire the benefits of vitamin D without unduly raising the risk of skin cancer.
Vitamin D deficiency is an indication of sunlight deficiency.
"People today work less outdoors and spend less time outdoors than at any previous time in history, which is why vitamin D deficiency is rising globally. In addition, when people are outside, many use sunscreens, which can significantly prevent the production of vitamin D in the skin," said Dr. Vieth. "With increasing amounts of evidence suggesting that vitamin D may protect against cancer, heart disease, diabetes, multiple sclerosis and other chronic diseases, it's more important than ever to examine this issue more closely."
"We urge public health entities to re-evaluate their current sun exposure policies and recommend UV exposure levels that promote a balanced, moderate approach that are both beneficial and safe," said Baggerly.