Catherine Saxelby's Foodwatch | Q. I know vitamin D is made by the sun but what does it do as a vitamin? What foods will I find it in?

Q. I know vitamin D is made by the sun but what does it do as a vitamin? What foods will I find it in?

 

A. Vitamin D is both a vitamin and a hormone. It was first discovered in the 1920’s as a result of the search for a cure for rickets, a disease causing softening of the bones in children.  It works by improving the absorption of calcium and phosphorus into the body so it helps to ensure strong bones and teeth as well as maintaining healthy nerve and muscle function.

Vitamin D can be made by the body from sunlight in a reaction that takes place in the skin. The UV rays from sunshine are essential for the reaction - in countries like Australia where there's plenty of sunshine most of the year, all the vitamin D our bodies need is be made via sunlight.

However there are groups who do not get adequate exposure to sunlight and may be deficient eg elderly people who never go outdoors due to ill-health, people with very dark skin, people who are covered due to religious reasons, babies born to women who are vitamin D deficient themselves.

How much do I need?

• 5 micrograms (mcg) or 200IU per day for women and men aged 19 to 50 years.
• 10mcg or 400IU per day for women and men aged 51 to 70 years.
• 15mcg or 600IU per day for women and men over 70 years.

Vitamin D is a fat soluble vitamin and is stored by the body, so toxicity from supplements is always a potential risk.  A maximum dose of 80mcg (3200IU) per day from vitamin D supplements is set as an upper limit to avoid excess. If you take supplements - including calcium supplements for bones -  check how much vitamin D you're taking in.

Best food sources of vitamin D

There are only small amounts of vitamin D in foods so it's often difficult to get enough vitamin D from diet alone, one of the main reasons for the popularity of cod liver oil in European countries where sunlight is limited.

Only a few foods (such as oily fish, egg yolk, milk and butter) naturally contain vitamin D. Margarine and a few brands of milk (eg Anlene) are fortified with added vitamin D, but most people in Australia only get around 25 per cent of their vitamin D from food.

 

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Comments (2)

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Hello
Thank you for a compact breakdown of simple understanding of Vitamin D.....would like to know if taking a daily total calcium tablet 825mg including Vitamin D3 combined with a good balanced diet has an effect on a drop in vitamin D levels from 94-59 in the last 12 months-58yr f/m? thanks Sharyn

S Williams , April 10, 2011

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hi
what other food products are fortified with vitamin D in Australia? May you give me a brand name, please?
Thanks

s RB , July 26, 2011

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