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The Sunshine Vitamin
posted: 7 January 2009 For those of us who like outdoor adventure and are often called “a bit mad” by our mates are probably quite familiar with broken bones. In some cases, a snapped ankle or wrist is inevitable (given the stunt) but if you look after your bones, these can sometimes be avoided. Maintaining strong healthy bones throughout life is the best way you can prevent spending weeks indoors wrapped in plaster cast!
Most people already 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 absorption; without it your digestive system cannot absorb as much calcium from food. It 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 this (dietary vitamin D) is not enough to meet our daily requirements. About 90% of our requirement comes from sunlight. Exactly how much sun exposure we need each day depends on:
The season and time of day
The less intense the sun, the more 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.
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 minutes in summer) because darker skin needs more UV to produce vitamin
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 is not a good enough reason to justify over exposure to the sun. During summer months 5-15 minutes outside of peak times should be enough for most people.
Coverage by clothing or sunscreen
Both sunscreen and clothing significantly reduce the amount of vitamin D you absorb, but commonsense prevails here folk…..the sunsmart message of slip, slop, slap and wrap still applies! Especially in summer, during the peak times of between 11am-4pm.
Kath Fouhy is a New Zealand Registered Dietitian. She combines her love of food and enthusiasm with sound nutrition advice to provide you with an individually tailored nutrition plan that is personally suited to your lifestyle and family.
Kath can help you with any nutrition related problem including: weight loss, high cholesterol, diabetes, and food allergies.
Kath is also a nutrition sponsor helping Aaron Fleming complete his Ironman dream, the official Dietitian to the Sarah Ulmer Brand, and a nutrition consultant for the NZ Academy of Sport.
For more information please visit Kath's website www.food4fuel.co.nz
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