06/07/2013 11:10 BST | Updated 05/09/2013 06:12 BST

Vitamin D - It's the Sunshine Vitamin

Or why UVB is the most effective, most reliable, most abundant and most natural source for Vitamin D!

Sun exposure to the skin is our best natural, intended and most effective but sadly, most neglected source of vitamin D.

Vitamin D sufficiency, along with diet and exercise, has emerged as one of the most important deficiency disease preventive factors in human health. Literally hundreds of studies now link vitamin D deficiency with significantly higher rates of many forms of cancer‚ as well as heart disease‚ osteoporosis‚ multiple sclerosis and many other conditions and diseases.

Because sunshine is a free commodity we can tend to take it for granted there is a strong advocate for natural vitamin D production through regular, non-burning sun exposure. Humans make 90 percent of their vitamin D naturally from sunlight exposure to our skin - specifically, from ultraviolet B exposure to the skin, which naturally initiates the conversion of cholesterol in the skin to vitamin D3. Few foods naturally contain or are fortified with supplemental vitamin D.

For example, an 8-ounce glass of whole milk is fortified with 100 IU (international units) of vitamin D - just 10 percent of what the most conservative vitamin D researchers now say we need daily. In contrast, sun exposure to the skin makes thousands of units of vitamin D naturally in a relatively short period of time. While vitamin D supplements are an alternative means of producing vitamin D when regular, non-burning sun exposure is not possible, oral supplementation of vitamin D is not nature's intended means of producing this vitamin. Now, over exposure to sunlight carries risks, the cosmetic skin care industry has completely misled the public into believing that any UV exposure is harmful. No research has shown that regular, non-burning exposure to UV light poses a significant risk of skin damage. Humans spend less time in the sun today than at any point in human history - which is why more than 1 billion people worldwide are vitamin D deficient.

Vitamin D Comes From the Sun

Sunlight is the best and only natural source of vitamin D. Unlike dietary or supplementary vitamin D, when you get your 'D' from sunshine your body takes what it needs, and de-metabolizes any extra. That's critical - as vitamin D experts and many health groups now advocate 1,000 to 2,000 IU of vitamin D daily - five to ten times the old recommendations. Because too much 'D' from dietary supplements may cause the body to over-process calcium, one of the main neutralizing mineral our body needs for maintaining our acid to alkaline balance. Due to a lack of research nobody really knows for sure how much supplementary vitamin D is safe. On the other hand, sunlight-induced vitamin D doesn't have that problem - it's the way your body is intended to make it! The most up to date research on vitamin D absorption is below:

Sunlight Exposure (full body exposure)* 3,000 - 20,000 IU

Salmon (3.5 oz. of fresh, wild salmon) 600 - 1,000 IU

Salmon (3.5 oz. of fresh, farmed salmon) 100 - 250 IU

Fortified Whole Milk, 8-oz. glass** 100 IU

Fortified Multi-vitamin 400 IU

* Sun exposure to the arms and legs for 10-15 minutes. The amount of vitamin D produced depends on the intensity of the UVB in the sun and many other factors. Darker-skinned individuals may need 5-10 times more exposure than a fair-skinned person to make the same amount of vitamin D. In northern climates sunlight is too weak in parts of the year to make any vitamin D - a period referred to as 'Vitamin D Winter'.

** Vitamin D is supplemented into milk. It doesn't occur naturally in milk.