The fact of the matter is, we live in a country that doesn’t get regular bouts of sun and unless you are running around outside completely naked everyday then you are most likely Vitamin D deficient.  Most of us are specifically low on Vitamin D3.

This is information gathered from an article by Rathish Nair and Arun Maseeh, called "Vitamin D: The Sunshine vitamin" (link at the end).

What is Vitamin D?

It is a fat soluble vitamin that is essential for the absorption of calcium in the body. It also helps in regulation of insulin.

How Vitamin D deficiency occurs:

As mentioned vitamin D is largely derived from the sun. However sun screen with a protection factor of 30 can reduce vitamin D synthesis in the skin by more than 95%. Individuals with darker skin tones require 3-5 times more sun exposure to make the same amount of vitamin D as those with light skin. Now does this mean you need to stop wearing sun screen? No, it means that you may have to look into other sources to get the vitamin D that your body needs.

How to get more vitamin Vitamin D:

Vitamin D is naturally absorbed by the body through the absorption of sunlight.

Foods that are high in vitamin D include: Fatty fish (tuna, mackerel, salmon), Beef Liver, Egg Yolk, Foods fortified with Vitamin D such as dairy, soy and cereals. You could also used vitamin D supplements to round out your vitamin D intake.

Benefits of Vitamin D:

Vitamin D has a significant effect against the following health issues;

Cancerous Cells

Heart Disease

Hypertension

Obesity

Type 2 Diabetes

Depression

Cognitive Impairment

Parkinson's Disease

Fractures and Falls

Autoimmune Diseases

Influenza

Bacterial vaginosis

Pelvic floor disorders

Age-related macular regeneration

Just to name a few.

Important Note:

As mentioned vitamin D is a fat soluble vitamin which means it needs healthy fat from the diet in order for the body to absorb and utilize it. It also requires magnesium so that the body is able to metabolize it.

For the full article:

Nair R, Maseeh A. Vitamin D: The "sunshine" vitamin. J Pharmacol Pharmacother [serial online] 2012 [cited 2018 Apr 29];3:118-26. Available from: http://www.jpharmacol.com/text.asp?2012/3/2/118/95506