Vitamin D is the "sun hormone" that, when produced sufficiently, improves mood and gives a feeling of balance. Vitamin D can be produced by the human body itself, provided that the skin is exposed to sunlight.
The hormone also strengthens the immune system and is important for the health of bones and muscles. Studies suggest that the concentration of vitamin D in the body has an influence on the development of depression and dementia as well as Alzheimer's disease. A vitamin D concentration of over 50 nmol/l would be necessary to avoid dementia.