Updates on COVID-19 (including visitor restrictions and mask requirements), monkeypox and flu. See Communicable Disease Updates

What Causes Vitamin D Deficiency?

Natural vitamin helps keep bones strong, prevent chronic conditions

Woman with hat sits in the sun and gets vitamin D.

Natural vitamin helps keep bones strong, prevent chronic conditions

Vitamin D is essential to good health. Sometimes called “the sunshine vitamin,” vitamin D earned that nickname because it’s produced naturally by our bodies when we’re exposed to ultraviolet light. 


This vitamin can also be obtained via foods, including egg yolks, fatty fish like salmon and mackerel, and fortified cereal and dairy products, or from supplements.


Vitamin D helps our bodies absorb calcium, maintain phosphorus and keep our bones strong. It also helps prevent cancer and chronic conditions like diabetes and may play a role in immune function. Yet despite its importance, it’s estimated that more than 40 percent of Americans don’t get enough.

Who’s at risk for Vitamin D deficiency? 

“If you live in an area with limited sun exposure, that increases the risk,” says Lydia Park, MD, an internal medicine physician at Scripps Clinic Anderson Medical Pavilion in La Jolla. 


“However, even in a sun-drenched city like San Diego, we are using sunscreens that block UV ray absorption like we were educated to do to reduce the skin cancer risk, and that prevents us from making more natural vitamin D.”


Certain populations are more prone to vitamin D deficiency as well. The elderly, people who have darker skin, and those with medical conditions, such as celiac disease, inflammatory bowel syndrome, or Crohn’s disease, also have a higher risk of developing a deficiency.

How does Vitamin D deficiency affect the body?

Persistent vitamin D deficiency in children can cause a condition called rickets that causes bowed legs.


In adults, it can cause the bones to soften. Doctors are also learning more about how vitamin D plays a role in mental health. Vitamin D deficiency has been linked to depression, anxiety and fatigue. It has also been linked to muscle injury risks in athletes.

What are symptoms of Vitamin D deficiency?

The symptoms of vitamin D deficiency may not be noticeable or may overlap with other common conditions. Your doctor can check your vitamin D levels with a simple blood test, and if necessary, help come up with a plan to correct the deficiency that may include limited sun exposure, dietary changes and the use of vitamin D supplements.


“Talk to your doctor about checking your vitamin D level,” says Dr. Park. “That will tell us how much to supplement and for how long.”

Cover of San Diego Magazine March 2022 issue.

This content appeared in San Diego Health, a publication in partnership between Scripps and San Diego Magazine that celebrates the healthy spirit of San Diego.