We are now learning that vitamin D is a very important substance in the body. Vitamin D is actually a misnomer as it is not actually a vitamin but a hormone.

We think that vitamin D, among other things, plays a role in the immune system. This can be seen in the association between low vitamin D levels and the higher incidence of diseases such as multiple sclerosis and certain types of cancer. If a person has a weaker immune system, and that would happen in someone who has multiple sclerosis and cancer, this would open them up to developing one of these conditions.

Therefore, the role of vitamin D in people who are suffering fatigue and tiredness in order to strengthen the immune system is important. Tiredness and fatigue is a sign that the immune system is not working properly, that it is rundown, for example in the case of a person not getting enough sleep, nutrition and exercise.

So how do we get vitamin D? Vitamin D is obtained through exposure to sunlight, where the vitamin D is converted to vitamin D3 in the skin. It can also be obtained in certain foods such as dairy and oily fish.

What is an appropriate level of vitamin D? The levels of vitamin D are measured in the blood. In Australia, optimal levels of vitamin D are probably about 120-130mmol/l. However, there is still debate about this.

What should we do if vitamin D is low? Firstly, we can get more sunlight. Twenty minutes of morning sunlight is a good start. However, in places where there is little sun, sun exposure throughout the day is advisable also. Vitamin D may also be supplemented, either as tablets or drops. It is difficult to overdose on vitamin D and therefore for most people, doses of 1000 international units to 2000 international units (which is one to 2 capsules or tablets) are quite safe, however it is advisable to test it before vitamin D is supplemented to see what the baseline level is.