Vitamin D is a fat-soluble vitamin that has long been known to help the body absorb and retain calcium and phosphorus - both of which are vital for bone building. Also, laboratory studies show that vitamin D can reduce cancer cell growth, help control infections and reduce inflammation. Many of the body's organs and tissues have receptors for vitamin D, which suggests how important it is to our bodies, in addition to bone health.

Few foods naturally contain vitamin D, although some foods are fortified with it. For most people, the best way to get enough vitamin D is to take a supplement, because it is difficult to consume enough through food. Vitamin D production in the skin is the main natural source of vitamin D, but many people have insufficient levels because they live in places where sunlight is limited in winter or because they have limited sun exposure due to staying indoors much of the year. Also, people with darker skin tend to have lower blood levels of vitamin D because the pigment (melanin) acts as a shade, reducing vitamin D production (and also reducing the harmful effects of sunlight on the skin, including skin cancer).

Vitamin D and health

Low levels of vitamin D in the blood have been linked to an increased risk of several diseases including:

Multiple sclerosis

Multiple sclerosis (MS)

Rheumatoid arthritis

Hypertension

Reduction of cancer incidence by 50%

Cardiological diseases

Depression

Obesity

According to researchers, the need for vitamin D increases in conditions such as:

Rheumatoid arthritis

Lupus erythematosus

Leukemia

Colon cancer

The darker our hair colour, the darker our hair colour, the browner our skin and the taller our height, the higher our height, the higher our vitamin D needs increase.

Food sources

Few foods are naturally rich in vitamin D3. The best sources are fatty fish flesh and fish oils. Smaller amounts are found in egg yolks, cheese and beef liver. Some mushrooms contain little vitamin D2; in addition, some mushrooms sold commercially contain higher amounts of D2 due to deliberate exposure to high amounts of ultraviolet light. Many foods and supplements are fortified with vitamin D, such as dairy products and cereals.

Cod liver oil

Salmon

Swordfish

Tuna

Orange juice fortified with vitamin D

Dairy and vegetable milks fortified with vitamin D

Sardines

Beef liver

Egg yolk

Fortified cereals

Sources:

https://www.hsph.harvard.edu/nutritionsource/vitamin-d/

https://www.flowmagazine.gr/vitamin_