It’s normal animal behaviour...Through the cooler months, we tend to hibernate indoors, writes Nutritionist and Naturopath, Renee Leonard-Stainton.
Spending time at your work desk is a little more tolerable, rather than it is when the sun is shining bright in summer and the beach is beckoning.
But braving the cold and standing outdoors daily is vital to help us avoid a vitamin D deficiency.
Why do we need vitamin D?
Vitamin D is required for the absorption and utilisation of calcium and phosphorus. It’s necessary for growth, and it also helps to prevent depression, protects against muscle weakness and is involved in regulation of the heartbeat.
Severe deficiency of vitamin D can cause osteoporosis and osteomalacia. Lesser degrees of deficiency may be characterised by loss of appetite, a burning sensation in the mouth and throat, diarrhoea, depression, insomnia, visual problems and weight loss.
How do we get vitamin D?
Vitamin D forms in the skin when it is exposed to UV from sunlight. It can also be obtained from some foods, but to a lesser extent. The best source of vitamin D is UV-B radiation from the sun. However, there is some uncertainty over how much sunlight different people need to achieve a given level of vitamin D.
There are no authorised guidelines to specify exactly how long you should aim to be in the sun for. This is because the time required to make sufficient vitamin D varies according to a number of environmental, physical and personal factors, which vary between individuals.
Are you susceptible to vitamin D deficiency?
Do you work long hours indoors? Remember to keep in mind that limited access to sunlight can develop a vitamin D deficiency. When the skin is exposed to the sun’s ultraviolet rays, a cholesterol compound in the skin is transformed into a precursor of vitamin D.
How much vitamin D is produced from sunlight depends on the time of day, where you live in the world and the colour of your skin. The more skin you expose, the more vitamin D is produced.
There are several forms of vitamin D, including vitamin D2 (ergocalciferol), which comes from food sources; vitamin D3 (cholecalciferol), which is synthesised in the skin in response to the sun’s ultraviolet rays; and a synthetic form identified as vitamin D5.
Foods that are good sources of vitamin D include:
- Fish liver oils
- Fatty saltwater fish
- Dairy products
It is also found in:
- Cod liver oil
- Dandelion greens
- Egg yolks
- Sweet potatoes
- Vegetable oils
How to avoid vitamin D deficiency
For most people, adequate vitamin D levels are reached through regular daily outdoor activity and incidental exposure to the sun. However, being tied to your desk due to work or study commitments can often mean we’re not getting enough time outdoors on a daily basis.
During summer, the majority of people can maintain adequate vitamin D levels from as little as five minutes of daily exposure to sunlight on their skin, on either side of the peak UV periods (10am to 3pm).
In winter, when UV radiation levels are less intense, people may need about two to three hours of sunlight to the skin, spread over a week to maintain adequate vitamin D levels. The time required is typically short and less than the time it takes to redden or burn.
To avoid a vitamin D deficiency, aim to head outdoors on your lunch break and be sure to include vitamin D rich foods into your diet too.
Speak to a health professional if you feel you may need supplements to correct a more severe deficiency.
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