In recent years it has been increasingly indicated that diet/nutrition is important in the pathogenesis, course and effectiveness of treatment of various mental disorders. Most of the research published so far has focused on the role of nutrition and nutrients in the development and treatment of depression. The results indicated a relationship between diet and risk of depression. Few studies have examined the relationship between diet and bipolar disorder (BD), although it can be assumed that some of the observations related to people with depression may be related to BD. The authors present an overview of the relationship between diet and bipolar disorder and the use of dietary interventions in the treatment of BD. They also discuss the use of nutrients, including polyunsaturated fatty acids, N-acetylcysteine, vitamin D, folic acid, and zinc, in the treatment of BD. For patients, the supplementation of mood disorders treatment with dietary recommendations, supplementation with selected nutrients, supplementation of micronutrients, may provide – in addition to indirect and direct effect on brain function – the possibility of greater co-participation in the treatment, enhancing the sense of control, coping, which may have a significant effect on the course of BD and the effectiveness of its treatment.