Karolinska Institutet has established the following vitamin D levels:

< 25 nmol/L = Deficiency
25-49 nmol/L = possible deficiency
50-250 nmol/L = normal
75 - 125 nmol/L = possibly optimal
> 250 nmol/L = possibly toxic

Vitamin D, which is actually a hormone, is important for our bones and teeth because it helps regulate calcium balance in the skeleton and maintain normal calcium levels in the blood. The vitamin also contributes to the normal function of the immune system and plays an important role in many processes in the body. Shop link: Are you deficient? Test at home and get an answer in a few minutes.

Vitamin D deficiency symptoms

Vitamin D deficiency in adults can lead to osteomalacia, which means softening of the bones. One important cause of osteoporosis is vitamin D deficiency. The vitamin is needed for calcium absorption in the intestine, and when calcium levels in the blood are low, calcium begins to be released from the skeleton to raise blood calcium levels.

Research findings also suggest that vitamin D deficiency may contribute to many other diseases. Associations have, for example, been observed with various infectious diseases, diabetes, MS and different forms of cancer. These findings do not show that the deficiency causes these diseases, but rather that it may be an important contributing factor.

Vitamin D deficiency in children can cause rickets, a condition that results in soft and deformed bones.

Certain groups are at risk of getting too little vitamin D and may therefore need supplements. Before starting supplements, it is advisable to check your vitamin D level because excessive amounts can be toxic. Too much vitamin D can cause nausea, bone problems and elevated calcium levels in the blood, which in turn may lead to calcium deposits in the kidneys and, in severe cases, kidney failure. It is not possible to reach excessively high levels through food alone.

According to a 2018 report from the Swedish Food Agency surveys indicate that a significant proportion of the population has vitamin D levels that are too low. The report suggests that around one in ten adolescents may have a deficiency. Recommendations have therefore been reviewed, with particular attention to risk groups and the fortification of certain foods.

Symptoms of vitamin D deficiency

Symptoms may include extreme fatigue, poor appetite, pain in the hands, arms, feet or lower back, and may also be associated with blood clots and obesity. Severe deficiency can cause cramps, although this is uncommon in Sweden. Mild deficiency is more common and can be difficult to detect because the symptoms are often diffuse.

Depression

Depression may in some cases be associated with low vitamin D levels.

Fatigue

A low value may mean that you feel more tired and lack energy.

Low mood and irritability

Low vitamin D levels may affect serotonin, sometimes referred to as a feel-good hormone.

High blood pressure

Vitamin D helps support healthy blood pressure, and high blood pressure may in some cases be associated with low vitamin D levels.

Weak muscles and reduced endurance

Vitamin D deficiency can affect the muscles and may lead to weakness and reduced endurance.

The symptoms may also have completely different causes

These symptoms can have many other causes. It is therefore advisable to test your vitamin D level before starting supplements. A deficiency can develop gradually, and a varied diet remains important.

Who is at risk and what is the daily requirement for vitamin D?

The average daily requirement is around 7.5 micrograms. Swedish recommendations for adults are 10 micrograms per day.

It may be difficult to get enough vitamin D if you are vegetarian or vegan, have allergies, do not eat fish or fortified foods, or get little sunlight. In some cases, a supplement may be needed during the winter months.

How do we get vitamin D?

Our main source of vitamin D is sunlight during the summer. Vitamin D is formed in the skin when it is exposed to sunlight. Around 5-10 micrograms can be produced through direct sun exposure for approximately 15 minutes two to three times per week, for example on the face and inner forearms. During the Swedish winter, sunlight is generally not sufficient for vitamin D production. Vitamin D stored in the body during summer can cover part of the need during winter, although this is relatively uncommon for people living in Sweden.

Vitamin D is also found in food, but often in limited amounts, and it can be difficult to get enough through diet alone. This is why sunlight in summer is so important. The largest amounts of vitamin D are found in fish, especially fatty fish such as salmon, mackerel, herring and tilapia. Other important sources include egg yolk, meat, certain mushrooms and foods fortified with vitamin D, such as dairy products, margarine and blended spreads.

Vitamin D occurs in two forms: vitamin D3, which is produced in our skin and is also found in foods such as fish, meat and eggs, and vitamin D2, which is found in mushrooms and fortified foods.