Vitamin D has been shown to be very important for wellbeing and is involved in supporting healthy immune function, maintaining a healthy skeletal mass and supporting a healthy mood. The term 'vitamin' is misleading as it really operates as a hormones in our bodies, helping to prevent chronic diseases such as cardiovascular disease, cancer and autoimmune diseases.
There is now a significant body of work which confirms the importance of Vitamin D. It is produced by our bodies and requires the action of UV light on our skin. However, many of us have low levels due largely to our lifestyles. Jobs which keep us indoors, sun avoidance with worries about skin cancer and simply not getting out enough can all predispose us to deficiency. Darker-skinned people may struggle to produce enough Vitamin D too, as dark skin absorbs less UV light than fair skin.
The Optimum range of Vitamin D levels is between 50-120 nmol/litre, with a 'sweet spot' of about 100 to prevent chronic diseases and maximise health. Above these levels, the evidence changes and higher Vitamin D levels may be less desirable. The best way to boost our levels is of course naturally via the sun, and recommendations are to expose 15% of our body surface area, eg both arms to the sun for 5-15 minutes , depending on our skin type. avoiding the harsh midday rays. It is important to cover up with suncream and be sun smart after that time. Sunburn not only predisposes to skin cancer but also lowers our Vitamin D levels.
It is reasonable to consider Vitamin D supplementation if you spend a lot of time indoors or are fair skinned and unable to be in the sun for long. Darker skinned individuals may also benefit from supplementation. Here in New Zealand, a single 50000 unit tablet can be taken monthly to maintain healthy levels. Research is still ongoing as to our winter Vitamin D levels, with some studies suggesting we are meant to have lower levels during the winter months. However, it is safe to continue all year round supplementation at this level and most of my patients report increased wellbeing and less Seasonal Affective disorder by maintaining good levels of Vitamin D during winter.