It’s important to have enough vitamin D, also known as the “sunshine vitamin,” for a number of reasons, from healthy bones to preventing some serious diseases. So how do we get it, and how much do we need?
There are two main ways we get our vitamin D. One is through diet from sources like oily fish (tuna, salmon, and mackerel), eggs, and also orange juice, milk and cereals fortified with vitamin D. The other way is synthesis triggered by UVB rays in the skin. The U.S. Institute of Medicine suggests a daily intake of 10-20 micrograms, for most healthy adults (2). It is estimated that sensible sun exposure on bare skin for 5-10 minutes 2-3 times per week allows most people to produce sufficient vitamin D (3).
Vitamin D helps promote the absorption of calcium helping maintain healthy bones and teeth, and also supports the immune system, while helping protect against a number of serious diseases (2). When we ingest vitamin D, our bodies convert it to calcitriol, the biologically active form of vitamin D. Some studies have even shown calcitriol can reduce cancer progression by slowing cancerous cell proliferation (3). Research also suggests vitamin D may also provide protection from hypertension, psoriasis, several autoimmune diseases (including multiple sclerosis and rheumatoid arthritis), and reduce the incidence of fractured bones (4).
A varied diet and a little sunshine on your skin should provide your body with the vitamin D you need for healthy bones and a healthy immune system.