How to boost your Vitamin D in winter
Vitamin D is known as the ‘sunshine vitamin’ – so how do you get enough when sunny days are in short supply?
Vitamin D is a beautiful thing – its benefits include everything from calcium absorption and bone growth to regulating our immune system and reducing the risk of cancers and heart disease.
Since we get most of our vitamin D intake through sun exposure, deficiency can become a problem during the not-so-sunny, cooler months.
University of Sydney School of Medical Sciences Professor of Endocrine Physiology Rebecca Mason says the general recommendation is to get 1000 international units (IU) – or 25 microgram – of vitamin D each day.
“Most vitamin D supplements on the market have this amount per capsule. One thousand IU per day is enough to raise vitamin D levels adequately in most people,” Prof Mason says.
But she says studies have shown that more than 40 per cent of people in southern parts of Australia have lower-than-recommended vitamin D levels during winter.
Vitamin D deficiency is linked to a number of health complications including less bone and reduced muscle function and may be associated with fatigue, depression and non-specific aches and pain, but often doesn’t cause any symptoms.
Who’s most at risk of vitamin D deficiency?
“People who have risk factors for vitamin D deficiency include individuals with pigmented skin; those who cover up for cultural, religious or other reasons, or who avoid sun exposure because they have very fair skin or on medical advice; people who are disabled or who have a chronic illness; older individuals; people who are obese or people who spend nearly all of the day indoors,” says Prof Mason.
So how do we prevent it?
First, consult with your GP
While deficiency in the vitamin is common during winter among all age groups and ethnicities, you shouldn’t assume you’re affected.
If you’re experiencing symptoms or at risk of deficiency, most doctors will suggest you get tested before making any dietary changes or introducing supplements.
“There is an argument that these people should discuss with their doctors the possibility of taking vitamin D supplements, especially during winter, but possibly all year,” says the professor.
Vitamin D supplements
Vitamin D supplements are widely available, but there are two types:
- Vitamin D3: Naturally produced in the body and easily absorbed.
- Vitamin D2: Produced in plants and vegan friendly, but possibly not as effective.
“Vitamin D3 (cholecalciferol) is the vitamin D made in skin of humans and other animals, whereas Vitamin D2 (ergocalciferol) is a similar compound, made in plants,” explains Prof Mason.
“Though vitamins D2 and D3 are similar, there is some evidence that vitamin D2 does not raise blood levels of vitamin D as much as vitamin D3, but vitamin D2 from diet is still useful. Most vitamin D supplements in Australia are vitamin D3.”
You can also increase your vitamin D levels by incorporating some vitamin D-rich foods into your meals. They include:
- Cod liver oil
- Beef liver
- Egg yolk
- Mushroom (mushrooms that have been exposed to a pulse of UV light or simply put out in the sun are a natural source of vitamin D2).
Additionally, there are a number of foods that may be fortified with vitamin D, including:
- Cow’s milk
- Alternative milk (soy, almond, coconut etc.)
- Orange juice
- Cereals and oatmeal
According to Cancer Council Australia, most people get adequate vitamin D levels through regular incidental exposure to the sun.
Spending time outdoors during daylight hours is still one of the most effective ways to get a direct source of vitamin D.
“Vitamin D stays around in the body for a fairly long time (weeks) – so if you spend some time outdoors and get some exercise during spring, summer and autumn, you will build up vitamin D stores that will help over winter,” says Prof Mason.
But remember to use sun protection if you don’t have much pigment in your skin.
“It seems that exercise, indoors or outdoors, can help to maintain vitamin D levels,” she adds.
Written by Charlotte Brundrett