When you think of nutrition, vitamins and other nutrients invariably come to mind. But not all vitamins that your body needs come from food. Technically, not all vitamins your body needs are even vitamins. Vitamin D fits both bills.

The good news is, there is an extremely easy way to get Vitamin D — go out in the sun, without sunblock, for 20 minutes a day. Your body will produce all the Vitamin D it needs. Unfortunately, those who live in temperate zones (north of Philadelphia and San Francisco) can’t get enough of the right UV rays from November to February. Supplements therefore can be a real help.

What is it and why is it necessary?

The activated Vitamin D in your body is a type of hormone called calcitriol. It plays a very important role in several body systems, from bones to thyroid health. It also plays a large role in the absorption of calcium and phosphorous.

A deficiency of Vitamin D in the body can cause serious pain and problems with these various symptoms. Vitamin D deficiency has even been linked to various cancers.

How to supplement

The inactive form of Vitamin D, cholecalciferol or Vitamin D3, doesn’t show up naturally in sufficient quantities in many foods. Certain oily fish and leafy greens are two main sources. Perhaps if you juice enough leafy greens you can get a good bit. Milk is fortified with Vitamin D as a way to avoid incidences of rickets in children, caused by Vitamin D deficiency.

Vitamin D3 is in many over-the-counter supplements. Vitamin D2, or ergocalciferol, is another form that you might see in supplements. But many people believe it to be less effective in the human body.

According to Dr. Greg Plotnikoff, Medical Director, Penny George Institute for Health and Healing, Abbott Northwestern Hospital in Minneapolis:

Because vitamin D is so cheap and so clearly reduces all-cause mortality, I can say this with great certainty: Vitamin D represents the single most cost-effective medical intervention in the United States.