Feasibility and Acceptability of a Healthy Nordic Diet Intervention for the Treatment of Depression: A Randomized Controlled Pilot Trial

Adherence to the nordic diet is associated with anxiety, stress, and depression in recovered COVID-19 patients, a case-control study

BACKGROUND

Follow-up of COVID-19 recovered patients to discover important adverse effects on other organs is required. The psychological health of COVID-19 patients may be affected after recovery.

AIM

We aimed to evaluate the association between adherence to the Nordic diet (ND) and psychological symptoms caused by COVID-19 after recovery.

METHOD

Dietary data on 246 qualified adults (123 cases and 123 controls). The dietary intake in this case-control study was calculated by a reliable and valid food frequency questionnaire (FFQ). Depression Anxiety Stress Scale (DASS), Pittsburgh Sleep Quality Index (PSQI), Insomnia Severity Index (ISI), and Short-Form Health Survey (SF-36) were used to analyze participant's anxiety, stress, depression, sleep quality, insomnia, and quality of life of participants.

RESULTS

There was a significant inverse relationship between total anxiety, stress, and depression scores and the intake of whole grains (P < 0.05). Furthermore, there was a significant inverse association between depression and fruit intake (P < 0.05). A significant negative correlation was found between insomnia and sleep quality and the intake of root vegetables (P < 0.05). In the multinomial-regression model, a significant association between the Nordic diet and anxiety, stress, and depression was found only in the case group (OR = 0.719, 95% CI 0.563-0.918, p-value = 0.008; OR = 0.755, 95% CI 0.609-0.934, P-value = 0.010, and, OR = 0.759, 95% CI 0.602-0.956, P-value = 0.019 respectively).

CONCLUSION

Adherence to the Nordic diet might reduce anxiety, stress, and depression in recovered COVID-19 patients.

Nordic diet and its benefits in neurological function: a systematic review of observational and intervention studies

Introduction

Neurological disorders have been considered the major contributors to global long-term disability and lower quality of life. Lifestyle factors, such as dietary patterns, are increasingly recognized as important determinants of neurological function. Some dietary behaviors, such as Nordic diet (ND) were likely to have protective effects on brain function. However, an understanding of the effectiveness of the ND pattern to improve neurological function and brain health is not fully understood. We review the current evidence that supports the ND pattern in various aspects of neurological function and addresses both proven and less established mechanisms of action based on its food ingredients and biochemical compounds.

Methods

In this systematic review, PubMed, Web of Science, and Scopus databases were searched from inception to February 2023. Observational and intervention studies were included.

Results

Of the 627 screened studies, 5 observational studies (including three cohorts and two cross-sectional studies) and 3 intervention studies investigating the association between ND and neurological function. Observational studies investigated the association of ND with the following neurological functions: cognition, stroke, and neuropsychological function. Intervention studies investigated the effects of ND on cognition and depression.

Discussion

Despite the limited literature on ND and its association with neurological function, several aspects of ND may lead to some health benefits suggesting neuroprotective effects. The current state of knowledge attributes the possible effects of characteristic components of the ND to its antioxidant, anti-inflammatory, lipid-lowering, gut-brain-axis modulating, and ligand activities in cell signaling pathways. Based on existing evidence, the ND may be considered a recommended dietary approach for the improvement of neurological function and brain health.

Systematic review registration

[https://www.crd.york.ac.uk/prospero/], identifier [CRD2023451117].

Dietary Patterns of Treatment-Resistant Depression Patients

Depression is a common mental disorder that occurs all over the world with treatment resistance commonly seen in clinical practice. Ketamine exhibits an antidepressant that is more often used in the case of treatment-resistant depression (TRD) in MDD and BP. Research emphasizes that a healthy diet and the nutrients it contains can lower the risk of developing depression and form a strategy that supports conventional treatment. The aim of the study was to evaluate the patients' diet and to analyze the effect of ketamine on food intake among patients with TRD. The study involved 15 patients suffering from treatment-resistant depression and 15 healthy volunteers. The data required for the analysis were collected using the food frequency questionnaire (FFQ) and 4-day food diaries. The study group was statistically significantly less likely to consume milk and plain milk beverages, plain white cheese, wholemeal bread, various vegetables, wine, and drinks. Our results show several disorders in the eating habits of patients with treatment-resistant depression. After the administration of ketamine, the patients consumed significantly less protein, fats, monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA), fiber, tryptophan, vitamins, and minerals compared to the control group. There is a lack of research describing the effects of ketamine on nutrition. In order to confirm the results of the study, more participants are required, and the assessment of food diaries filled in at the patient's home with a longer interval after the last dose of ketamine as well.

A Possible Antidepressive Effect of Dietary Interventions: Emergent Findings and Research Challenges

Purpose

Despite recent advancements in the treatment of depression, the prevalence of affected individuals continues to grow. The development of new strategies has been required and emerging evidence has linked a possible antidepressant effect with dietary interventions. In this review, we discuss recent findings about the possible antidepressant effect of dietary interventions with an emphasis on the results of randomized controlled trials.

Recent findings

A high consumption of refined sugars and saturated fat and a low dietary content of fruits and vegetables has been associated with the development of depression. There is evidence supporting a small to moderate beneficial effect of a Mediterranean-type diet in depression. In addition, new dietary protocols are being studied for their use as possible interventions, such as the ketogenic diet, Nordic diet, and plant-based diet.

Summary

Lifestyle interventions surrounding diet and nutrition are a relatively affordable way to enhance response to treatment and to be employed as an adjunct in mental health care. Most studies, however, are limited by the difficulty in controlling for the placebo effect. Mediterranean-style diets seem to be the most promising as an adjunctive treatment for mood disorders. Larger randomized controlled trials that could assess predictors of response to dietary interventions are needed to establish a clear positive effect of diet and guide clinical care and nutritional recommendations concerning mental health care.