Understanding Vitamin D Deficiency

Vitamin D deficiency has been linked to depression, cancer, and even heart attacks.  But are these claims true? Should you get your Vitamin D levels checked? The House Call Doctor separates Vitamin D facts from fiction.

Sanaz Majd, MD
4-minute read
Episode #150

Last week, we discussed the importance of the parathyroid gland in regulating bone health. We talked about how the parathyroid uses Vitamin D to help perform its job.  So let’s learn more about Vitamin D, often referred to as the “sunshine Vitamin” for reasons we will soon learn.

I frequently encounter patients who ask me about Vitamin D and request to have their “levels” checked.  Vitamin D deficiency has received a lot of press in the recent years. It has been suggested as the end-all answer to everything from depression, to prevention of cancer, and even heart attacks.  Most experts agree that the Vitamin D craze is over-hyped (as are many medical topics once the media gets a hold of them). 

See also: How the Media Sensationalizes Science


Nevertheless, Vitamin D deficiency can be an important medical issue for some patients - but who?  What is all the hoopla over this vitamin about?  And if you live in Southern California or other sunny parts of the world, should you even be worried about Vitamin D levels since you tend to get enough sun exposure?  Let’s find out.>


What Is Vitamin D?

Vitamin D is a key component for bone health.  It helps to absorb calcium in the intestine in order to help build bone.  It also helps to suppress a hormone called Parathyroid Hormone that tends to break down bone.  Check out last week’s episode to learn more about the parathyroid gland.

There are two main sources Vitamin D:

  1. Your skin: Believe it or not, Vitamin D is actually produced underneath the skin when it is exposed to sunlight, hence the term “sunshine vitamin.”  This production slows down with age, however, and those with darker skin may require more sunlight to produce sufficient Vitamin D levels.  Of course skin cancer is a big concern for experts – we don’t want to trade one disease for another.  So how do we balance sun exposure and Vitamin D production in a healthy way?

  2. Your diet: Vitamin D is also ingested in the foods we consume.  The largest supply often comes from fortified milk, which contains about 100 IU’s (international units) per 8 oz.  But what to you do if you are lactose intolerant?

Why Is Vitamin D Important?

Bone health becomes an issue mainly in the elderly population who may more easily fracture due to osteoporosis (which is low bone density). But in reality, bone health should be something we think about at any age – bone strength and building begins when we are young.  So even though not everyone may need to have their Vitamin D levels examined, it would be wise to make sure you get enough throughout your life to maintain the strongest possible bones by the time you are older.  Studies also show that Vitamin D may reduce the risk of falls and fractures in the elderly. 

Severe Vitamin D deficiencies are rare in developed countries like the U.S., but mild deficiencies do happen and may contribute to osteoporosis. Some of the lowest Vitamin D levels in the world have been found in people of the Middle East and South Asia. 


Please note that all content here is strictly for informational purposes only. This content does not substitute any medical advice, and does not replace any medical judgment or reasoning by your own personal health provider. Please always seek a licensed physician in your area regarding all health related questions and issues.

About the Author

Sanaz Majd, MD

Dr. Sanaz Majd is a board-certified Family Medicine physician who graduated from Drexel University College of Medicine in Philadelphia. Her special interests are women's health and patient education.