Vitamin D - The Sunshine Vitamin

How Vitamin D Helps you Develop Strong and Healthy Bones

Those who like extreme and/or outdoor adventure sports are probably quite familiar with broken bones. Sometimes these injuries are inevitable, but to give yourself any chance of avoiding weeks wrapped up in plaster, maintaining strong, healthy bones are a must.

Most people know that dairy products and other foods rich in calcium are essential for developing and maintaining strong bones, but did you know that calcium cannot do its job without adequate vitamin D. Vitamin D allows calcium to be absorbed by your digestive system and is also needed for the proper mineralisation and growth of bone. 

Vitamin D is known as the sunshine vitamin because that is where we get most of it from. It occurs naturally in small amounts in some foods but generally not quantities that will to meet our daily requirements. About 90% of our requirement comes from sunlight. Exactly how much sun exposure we need each day depends on:

1. The season and time of day - The less intense the sun, the more exposure that is needed. For example, between October and March most people venturing outdoors exposing their face, arms or legs should be able to achieve adequate vitamin D levels through incidental outdoor UV exposure outside peak UV times (11am-4pm). In the winter, sun exposure between 11am-4pm generally isn’t a problem because UV levels are lower.
2. Your skin type - If you burn easily you may only need five minutes sun exposure before 11am or after 4pm to achieve adequate vitamin D levels. Someone who tans more easily or has darker skin will need more time (e.g. 15 mins in summer) because darker skin needs more UV to produce vitamin D.
3. Duration of exposure to sunlight - I’m sure you are all well aware that ultraviolet light is the radiation most commonly associated with sunburn and skin cancer, so using vitamin D as a reason to over expose yourself to the sun is not acceptable. During summer months 5-15 minutes outside of peak times should be enough for most people.
4. Coverage by clothing or sunscreen - Both sunscreen and clothing significantly reduce the amount of vitamin D you absorb, but commonsense always should prevail. The sunsmart message of slip, slop, slap and wrap still applies! Especially in summer, during the peak times of between 11am-4pm.

By Kath Fouhy, BSc, PG DipDiet, NZRD - 17/01/09

Pulse Personal Training – It’s About Success - www.PulsePT.co.nz