As we come into the cooler months, it becomes a little harder to soak up the sun. That usually means a drop in the level of vitamin D in your body. Should you worry if you’re not getting as much sunlight as you did over summer? And how else can you get enough of this essential nutrient?

What is vitamin D?
Vitamin D is a little different from other vitamins in that we can get small amounts of it from our food, but our main source is through the synthesis of it in our skin. Vitamin D is converted to a hormone in the kidneys and regulates body functions. It also enhances the small intestine’s ability to absorb calcium from food, which is vital for bone strength, and helps to keep our muscles functioning.

What happens if we don’t get enough vitamin D?
Low levels of vitamin D can cause rickets (a childhood disease in which the bones soften and become deformed), osteoporosis (thinning of the bones which causes fractures), and perhaps even a predisposition to breast, bowel and prostate cancers.

Where can we get vitamin D?
Some foods contain vitamin D, including fish, eggs, mushrooms and margarine. However, these foods aren’t enough to give us an adequate dose of vitamin D. The best source is from the sun. The interaction of UV rays with a steroid in our skin produces vitamin D.

How much do we need?
Australian guidelines specify that we should have a blood level of vitamin D of at least 50 nanomoles per litre. This can fluctuate a lot throughout the year, depending on the weather. On a summer’s day, you can absorb this much vitamin D with just five to 15 minutes of direct exposure to the sun. People with fair skin need less sun exposure, and people with dark skin need a bit more. Once your body has absorbed enough vitamin D, over-exposing your skin to the sun won’t give you any additional health benefits.

When is the best time to soak up the sun?
The best part of the day to get sun exposure in summer is the mid-morning or mid-afternoon. You need to do this most days every week. In winter, it depends on where you live. Northern Australians should get several minutes of sun exposure each day around noon, while people in the south should stay out a little bit longer with some skin exposed – which might be tricky given the chilly weather.

Where is the balance between vitamin D deficiency and skin cancer?
Not enough sun exposure causes vitamin D deficiency, while too much sun exposure causes permanent cell damage and skin cancer. So where is the balance? Getting five to 15 minutes of direct sun exposure on most days will provide enough vitamin D to keep your body healthy. As soon as you reach this quota, cover up with sunscreen, long sleeves, sunglasses and a hat. Seek shade whenever possible and avoid going outside between 10:00am and 3:00pm, when the sun’s UV radiation is the most damaging. Taking these steps will help prevent skin cancers like melanoma.

Who is at risk of vitamin D deficiency?
A vitamin D level below 20 nanomoles per litre is generally considered a deficiency, and there are some groups who are at higher risk of this, including:

• People with very dark skin
• People who cover their bodies for religious or cultural reasons
• People who work night shifts or office workers who spend most days indoors
• Older Australians who may not lead active lives
• People with a high body fat percentage
• Vegans and vegetarians
• People taking medications including corticosteroids or weight loss drugs
• People with constant joint or muscle aches
• People suffering from depression, headaches or inflammatory bowel disease

When should you take supplements?
You probably don’t need to take supplements unless you’re in a high-risk group or have been advised to take supplements by your doctor. Generally, getting out in the sun a little bit each day will boost your vitamin D levels. Always remember to use adequate sun protection when you’re outdoors for longer than 15 minutes, and get regular skin cancer checks from a medical professional so that any skin cancers can be caught early.