Vitamin D - The sunshine vitamin
Have you been told that your vitamin D levels are low? Do you have limited sun exposure?
Why do we need vitamin D?
Vitamin D has anti-inflammatory properties and plays an important role in bone health and neuromuscular function by regulating calcium absorption in the body. It is also essential for healthy immunity and skin and there is increasing evidence associating vitamin D with reductions in anxiety and depression.
How do we get vitamin D?
The main source of vitamin D is sunlight. Exposing the hands, face and arms to sunlight (without sunscreen) for 5-15 minutes a day, 2-3 times a week will provide adequate amounts of vitamin D for most people. During the hot summer months, I recommend getting your vitamin D hit in the morning before 10am (especially if you’re fair-skinned), however it is ok to get your daily sun exposure a bit later in winter.
Fish is a rich source of vitamin D, especially oily fish such as salmon, mackerel and herring. Other dietary sources include meat, milk, eggs, mushrooms and fortified foods such as orange juice, cereals and some breads.
Who is most at risk for vitamin D deficiency?
People at risk of deficiency include:
- night workers
- dark-skinned people
- people who cover their skin (e.g. for religious reasons)
- elderly people living in residential care
- housebound individuals
- people with malabsorption conditions such as irritable bowel syndrome
If you are at risk of deficiency or a blood test confirms that you have low vitamin D levels, you may benefit from supplementation. The “normal” reference range for vitamin D is >50, however nutritionists and naturopaths consider this to be too low. We use the “optimal” range and prefer client’s vitamin D levels to be closer to 100.
How to choose the best vitamin D supplement
There are two forms of vitamin D:
- D2 (ergocalciferol) is the form of vitamin D found in plant sources (e.g. mushrooms grown in UV light) and fortified foods.
- D3 (cholecalciferol) is the form that is naturally stored in the body and is found in animal foods (e.g. fish, liver, egg yolk, butter).
Both forms of vitamin D are well absorbed in the body, however D3 has been shown to more effectively increase vitamin D levels in the body than vitamin D2 so that is the supplement I tend to prescribe in clinic.
If clients are low in vitamin D, I generally recommend that they take a supplement that also contains vitamin K2. Vitamin K2 maximises the effectiveness of D3 by ensuring that the calcium absorbed by the vitamin D is transported to the places it is needed (ie. the bones), rather than allowing calcium to build up in the arteries. D3/K2 combined supplements are readily available and inexpensive.
I advise having your vitamin D levels tested before supplementing, especially with children, as excess supplemental vitamin D can result in toxicity and side effects such as nausea, vomiting, headache, dizziness and blurred vision.
References
Hechtman L, 2019, Clinical Naturopathic Medicine (2nd ed), Elsevier, Australia.
Arnason A, 2018, ‘Vitamin D2 vs D3: What’s the difference?’, Healthline, New York, viewed 20 September 2022, https://www.healthline.com/nutrition/vitamin-d2-vs-d3