Abstract

     Introduction: Individuals with bipolar disorder (BD) have higher rates of unhealthy lifestyles and risk for medical comorbidities Research currently suggests that dietary factors may play a role in the development of depression and anxiety. Therefore, nutritional approaches are potential strategies for the treatment of BD. The aim of this review is to summarize the available evidence on nutrition and BD. Materials and Methods: The paper was developed based on PRISMA 2020 guidelines. The search was conducted in Sep-2021 using PubMed and Cochrane Library, augmented by manually checked references lists. The search found 986 studies, of which 47 were included, combined with 13 from reference lists, totaling 60 studies. Results: There were 33 observational trials, of which 15 focused on fatty acids, 9 on micronutrients, 5 on specific foods, 4 on macro and micronutrients. The 27 interventional studies mainly focused on fatty acids, micronutrients and N-acetylcysteine (NAC). Discussion: Dietary intake or supplementation of unsaturated fatty acids, mainly Omega-3 seems to be associated with improved BD symptoms, along with seafood, folic acid and zinc. Studies found variable, mainly non-significant impacts of creatine, carnitine, vitamin D, inositol or NAC supplementation on BD. There are promising results associated with Coenzyme Q10 (Coq10) and probiotics. Taken together, these preliminary findings suggest that dietetic approaches might be included as part of BD treatment. Also considering the high risk of metabolic disorders in individuals with BD, they should be encouraged to choose healthy dietary lifestyles, including daily intake of fruits, vegetables, seafood and whole grains.

Introduction

     Nutritional psychiatry is a rapidly expanding field of study, which has recently benefited from the advances of neurosciences, epidemiological research on risk factors as well as the renewed interest in the role of lifestyle in mental health [1]. Extensive observational evidence consistently demonstrates that diet quality is a predictor of depression risk – independent of other factors, such as education and body weight [2]. Moreover, randomized controlled trials in people with even severe major depressive disorder show efficacy and cost-effectiveness in improving depression symptomatology [3–۷]. Concordantly, meta-analytic data confirms that dietary change improves depression symptoms in both clinical and non-clinical populations [8]. Considering that poor diet and dysfunctional eating behaviors are modifiable risk factors, it is possible that these will be converted into critical interventions for mental health [3,9,10]. Indeed, new clinical practice guidelines for mood disorders include diet, along with other aspects of lifestyle, as foundational and ‘non-negotiable’ treatment targets [1,11].

Results 

Search results

     The final search yielded 986 studies. After removing duplicates (N = 60), studies in other languages and publications prior to 2001 (N = 97), titles and abstracts from 829 studies were screened. Studies that did not clearly meet the inclusion criteria and/or met the exclusion criteria were excluded. The remaining 57 studies were analyzed by full text reading, after which 10 were excluded because they did not meet the full inclusion criteria. This led to 47 included studies, which were combined with 13 studies that were obtained from the bibliography from the included studies and reviews found in the search, totaling 60 studies (Figure 1).