During the winter months it’s common for many to be concerned with the lack of sunshine and their overall health, especially during cold season. When it comes to taking supplements, it’s important to do your research, and make the distinction between popular myths and scientifically proven facts.

It is widely known that vitamin D can be synthesized from sunlight, and that during gloomy winter season many people experience a deficit of vitamin D, and consequently, depression. However, it has not yet been scientifically proven that the correlation between low levels of vitamin D and a depressed mood are causal.

Let’s look at the biochemistry of vitamin D. A steroid known as 7-dehydrocholesterol exists inside the skin. When photons of light hit it, they break one of its bonds. The result is a form of vitamin D called vitamin D3. D3 then travels to the liver and kidneys. The liver stores the element, while the kidneys convert D3 into D.

This conversion process also occurs when you consume food that contains vitamins D2 (plant-sourced products such as mushrooms) and D3 (animal-sourced products such as butter).

Vitamin D is used by our body to balance levels of calcium and phosphorus, facilitate growth of bones and teeth and regulate functioning of our nervous system. Many products – milk, cereals, eggs, fish – are either fortified with vitamin D3 or contain it naturally. Therefore, many of us do not need supplements because we get enough of the essential element from food. Excess of vitamin D might lead to negative symptoms, such as reduction in appetite and even vomiting. This occurs when our body attempts to get rid of the excess calcium.

A Canadian research team lead by Professor Rebecca Anglin in 2013 concluded that "The observational studies to date provide some evidence for a relationship between vitamin D deficiency and depression," however, more research is needed to confidently determine a directly causal relationship. Although subjects in many studies with depressive symptoms improve after supplementing with vitamin D, it is still uncertain whether they were depressed because of a vitamin D deficit, or if vitamin D directly cures feelings of sadness.

Nevertheless, if you notice symptoms that are proven to correlate with deficiency – weakened immune response, sadness - you could consider taking the supplement.

Be aware, though, that low levels of magnesium impede the effective intake of vitamin D. Wondering if you're deficient? You're in luck, because this can be determined with a simple blood-test. Just ask your doctor.

Interestingly, vitamin D is proven to be involved in dormancy. When vitamin D pathways are blocked in young fish due to adverse ecological conditions, the vertebrates stop developing. It is even suggested that continued research on vitamin D might help to design methods to induce dormancy in people for future space travels.

Vitamin D is not just your average element!