Sunscreen Use, Chronic Disease Linked to Vitamin D Deficiency

The study's authors say the findings show the need to find the right balance between guarding against skin cancer and getting enough vitamin D.

The rise of diseases like type 2 diabetes (T2D), along with widespread use of sunscreen to fight skin cancer are blamed for worldwide deficiencies in vitamin D, according to a new study in The Journal of the American Osteopathic Association.

Vitamin D, which the authors say is a hormone rather than a vitamin, is produced when the body is exposed to sunlight. It aids immune function, reduces inflammation, and helps control cell growth. The study published Monday found that nearly 1 billion people may have insufficient levels of vitamin D because of chronic disease or because they are not getting enough sun exposure. The Endocrine Society defines insufficiency as between 21 and 30 ng/ml, while deficiency is defined as 20 ng/ml and below.

Finding the right balance between guarding against skin cancer and getting generating vitamin D is key.

“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,” Kim Pfotenhauer, DO, assistant professor at Touro University, said in a statement. “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.”

Chronic diseases add to the problem because they make it more difficult for people to absorb vitamin D from food. Besides T2D, the diseases include kidney disease, Crohn’s disease, and celiac disease. Diabetes, and T2D in particular, has soared in recent decades: the World Health Organization reports that the number of people with the disease rose from 108 million in 1980 to 422 million in 2014; prevalence increased from 4.7% to 8.5% in that period.

Symptoms of vitamin D deficiency include muscle weakness and bone fractures. People with these symptoms should be screened for chronic diseases and should be checked to see if their vitamin D levels are low. To boost vitamin D levels, people can spend 5 to 30 minutes per day in the sun midday twice a week. Drinking milk or eating breakfast cereals can also boost vitamin D levels.

Pfotenhauer advises that people who go for a walk midday not wear sunscreen during these brief outings. “A simple walk with arms and legs exposed is enough for most people,” she said.

People with paler skin convert sunlight to vitamin D more quickly than those with darker skin, which may help explain why they study found that 95% of African American adults have vitamin D deficiency or insufficiency.

Reference

Pfotenhauer KM, Shubrook JH. Vitamin D deficiency, its role in heath and disease, and current supplementation recommendations. J Am Osteopath Assoc. 2017; 117(5):301 DOI: 10.7556/jaoa.2017.055.