Vitamin D is a hormone-like vitamin that is very important for overall good health and strong, healthy bones. Vitamin D improves the absorption, transport, and use of calcium and phosphorus, which are necessary for bone and tooth formation. It is also a factor in ensuring your muscles, heart, and lungs function optimally.
Why do we need vitamin D?
Vitamin D plays an important role in the body's cell division process and contributes to the normal function of the immune system. It simply helps cells throughout the body communicate properly. People with an adequate level of vitamin D are usually much better equipped to fight colds and other illnesses.
How do we get vitamin D?
Vitamin D is mainly found in fatty fish, wild mushrooms, and egg yolk. However, it is difficult to get enough through diet alone. If you are vegetarian or vegan, it is especially challenging.
Otherwise, vitamin D mainly comes from your skin when it is exposed to sunlight. Your body then goes through a number of chemical processes to convert it so that your body can use it in the best way. However, the amount of vitamin D you get from sunshine depends on:
- The time of day – your skin produces more if exposed during midday.
- Where you live – the closer to the equator you live, the easier it is for you to produce vitamin D from sunlight year-round. In the Nordic countries, we can only absorb vitamin D from the sun during the summer months.
- The color of your skin – lighter skin produces vitamin D faster than darker skin. For example, if you have very light skin, it may take about 15 minutes to produce enough vitamin D, but if you have dark skin, it can take up to 2 hours.
- The amount of skin you expose – the more skin you show to the sun, the more vitamin D your body produces.
- Because the sun’s rays are weaker and the days shorter during autumn and winter in Sweden – and because we spend less time outdoors and wear more clothes – we basically produce no vitamin D from the sun between October and April. Therefore, a vitamin D supplement can be very valuable during this period.
Low levels of vitamin D can affect energy, mood, depression, immune defense, and more. One way to find out your exact need is to measure vitamin D in the blood either through a therapist, at a health center, or privately at places like Werlabs or Blodkollen.
Vitamin D supplements
Vitamin D comes in two forms: D2 and D3.
Both have been shown to be effective in clinical studies for raising vitamin D levels in the blood, but vitamin D3 is preferred because it is much better utilized by the body and is the form that comes from natural sources: the sun and our food.
Vitamin D3 can be extracted in different ways, and today there are mainly two natural sources used in supplements: sheep’s wool or lichen. Both are effective and good sources of active vitamin D3, and which one you choose is entirely up to you. The one from lichen is 100% plant-based, which can be an advantage for many.
A vitamin that can be good to combine with D3 is vitamin K, which is also fat-soluble and works in synergy with vitamin D to build strong bones, as well as being important for blood clotting ability.
How much vitamin D do we need?
The best way to find out exactly how much vitamin D you need is to take a supplement for a couple of months and then have a blood test. The absorption of vitamin D supplements is individual and influenced by several factors. Therefore, it is impossible to give a recommendation that applies to everyone.
The test is called 25-OH-D and can be ordered through a health center or private laboratory.
For most people, the optimal target is a blood level of 50-80 ng/ml or 125-200 nmol/L (there are two different ways to express vitamin D measurements. In Sweden, ng/ml is most common).
That said, we recommend these doses as a starting point during the winter months in the Nordic region:
Adults: 1000-2500 IU daily (or 5000 IU every other day).
Children under 12 years: 500 – 1000 IU daily.
