Vitamin D is a hormone-like vitamin that is very important for good overall health and strong, healthy bones. Vitamin D improves absorption, transport and utilization of calcium and phosphorus which in turn 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 appropriate levels of Vitamin D are typically much better equipped to fight colds and other illnesses.
How do we get Vitamin D?
Vitamin D is found primarily in fatty fish, wild mushrooms, and egg yolks. However, it is difficult to get sufficient amounts through diet. If you are vegetarian or vegan, it is especially challenging. Vitamin D otherwise comes mainly from your skin when exposed to sunlight. Your body then goes through a number of chemical processes to transform it so that your body can use it optimally. The amount of vitamin D you get from sunlight depends on:
The time of day – your skin produces more if you expose it during midday.
Where you live – the closer to the equator you live, the easier it is for you to produce vitamin D from sunshine year-round. In the Nordic countries, we can only utilize vitamin D from the sun during summer.
Your skin color – light skin produces vitamin D faster than darker skin. For example, if you have very light skin, it can take about 15 minutes to produce adequate 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 days are shorter during autumn and winter in Sweden – and we spend less time outdoors and wear more clothes – we in Sweden produce virtually no vitamin D from the sun between October and April. Therefore, a vitamin D supplement can be of great value during this period. Low levels of vitamin D can affect energy, mood, depression, immune system, and more. One way to determine your exact needs is to measure vitamin D in your blood either with a therapist, at a health center, or privately through services like Werlabs or Blodkollen.
Vitamin D Supplements
Vitamin D comes in two forms: D2 and D3. Both have proven effective in clinical studies for raising vitamin D levels in the blood, but vitamin D3 is preferable because it is utilized much better in 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 primarily two natural sources used in supplements: cotton grass or lichen. Both are effective and good sources of active vitamin D3, and which one you choose is entirely up to you. The lichen-derived form is 100% vegetarian, which can be an advantage for many. A vitamin that can be beneficial to combine with D3 is vitamin K, which is also fat-soluble and works in synergy with vitamin D to build strong bones, and is important for blood's coagulation ability.
How much Vitamin D do we need?
The best way to determine exactly how much vitamin D you need is to take a supplement for a couple of months and then get a blood test. The absorption of vitamin D supplements is individual and affected by several factors. Therefore, it's impossible to give a recommendation that applies to everyone. The test is called 25-OH-D and can be ordered through your healthcare center or a private laboratory. Optimal for most people is to aim for a blood value of 50-80 ng/ml or 125-200 nmol/L (there are two different ways to express measurement values for vitamin D. In Sweden, ng/ml is most common). That said, we recommend these doses as a starting point during the winter months in the Nordic countries:
Adults:
1000-2500 IU daily (alternatively 5000 IU every other day).
Children under 12 years:
500 – 1000 IU daily.
