Slathering on sunscreen could be one of the factors behind people becoming deficient in vitamin D, a study suggests.
Nearly one billion people worldwide might have deficient or insufficient levels of vitamin D due to chronic disease and insufficient sun exposure related to sunscreen use, according to research published in the Journal of the American Osteopathic Association.
Kim Pfotenhauer, an assistant professor at Touro University and contributor to the study, said: "People are spending less time outside and when they do go out they're typically wearing sunscreen, which essentially nullifies the body's ability to produce vitamin D.
"While we want people to protect themselves against skin cancer, there are healthy, moderate levels of unprotected sun exposure that can be very helpful in boosting vitamin D."
Vitamin D is produced when skin is exposed to sunlight and a deficiency can lead to muscle weakness and bone fractures.
Chronic illnesses such as Crohn's or coeliac disease might lead to the malabsorption of the vitamin, while poor diet can also cause deficiency.
Spending five to 30 minutes in the noon sun twice a week could help to increase and maintain healthy vitamin D levels, the osteopathic association said.
It said it was "important to forgo sunscreen during these sessions because SPF 15 or greater decreases vitamin D3 production by 99 per cent".
