Associations and effects of omega-3 polyunsaturated fatty acids on cognitive function and mood in healthy adults: a protocol for a systematic review of observational and interventional studies

Possible antidepressant mechanisms of omega-3 polyunsaturated fatty acids acting on the central nervous system

Omega-3 polyunsaturated fatty acids (PUFAs) can play important roles in maintaining mental health and resistance to stress, and omega-3 PUFAs supplementation can display beneficial effects on both the prevention and treatment of depressive disorders. Although the underlying mechanisms are still unclear, accumulated evidence indicates that omega-3 PUFAs can exhibit pleiotropic effects on the neural structure and function. Thus, they play fundamental roles in brain activities involved in the mood regulation. Since depressive symptoms have been assumed to be of central origin, this review aims to summarize the recently published studies to identify the potential neurobiological mechanisms underlying the anti-depressant effects of omega-3 PUFAs. These include that of (1) anti-neuroinflammatory; (2) hypothalamus-pituitary-adrenal (HPA) axis; (3) anti-oxidative stress; (4) anti-neurodegeneration; (5) neuroplasticity and synaptic plasticity; and (6) modulation of neurotransmitter systems. Despite many lines of evidence have hinted that these mechanisms may co-exist and work in concert to produce anti-depressive effects, the potentially multiple sites of action of omega-3 PUFAs need to be fully established. We also discussed the limitations of current studies and suggest future directions for preclinical and translational research in this field.

Relationship between Dietary Macronutrients Intake and the ATHLOS Healthy Ageing Scale: Results from the Polish Arm of the HAPIEE Study

Background: Despite extensive research, our knowledge on the relationship between nutrition and healthy ageing is limited. The aim of this study was to evaluate the associations between the intake of macronutrients and a single measure of healthy ageing (ATHLOS Healthy Ageing Scale). Methods: A cross-sectional analysis was performed using data from 9906 randomly selected citizens of Krakow (Poland) who were 45–69 years of age and participants of the Health, Alcohol and Psychosocial factors in Eastern Europe (HAPIEE) study. Macronutrient intake was evaluated using a food frequency questionnaire. ATHLOS Health Ageing Scale was estimated from 41 variables in pooled data from 16 cohorts. Standardized beta coefficients were estimated using multivariable linear regression models. Results: In multivariable adjusted models, there were significant positive associations between the ATHLOS Healthy Ageing Scale score and intake of protein (b = 0.030, 95% CI 0.001; 0.059 in men; b = 0.056, 95% CI 0.027; 0.085 in women), monounsaturated fatty acids (MUFA) (b = 0.042, 95% CI 0.013; 0.071 in men; b = 0.035, 95% CI 0.006; 0.064 in women), polyunsaturated fatty acids (PUFA) (b = 0.053, 95% CI 0.024; 0.082 in men; b = 0.063, 95% CI 0.034; 0.092 in women), and omega-3 PUFA (b = 0.031, 95% CI 0.002;0.060 in men; b = 0.054, 95% CI 0.026; 0.082 in women). Carbohydrate intake was inversely associated with the ATHLOS Healthy Ageing Scale in women. Total fat intake was positively associated with the ATHLOS Healthy Ageing Scale in men. Conclusions: A number of nutrients were associated with the healthy ageing score, suggesting that dietary habits may play an important role in healthy ageing. Further research in other settings and with a prospective design is strongly warranted.

The effects of a high eicosapentaenoic acid multinutrient supplement on measures of stress, anxiety and depression in young adults: Study protocol for NutriMOOD, a randomised double-blind placebo-controlled trial

Anxiety disorders affect nearly 20% of young adults aged 18-29 years. First-line treatment for anxiety disorders comprises pharmacotherapy and Cognitive Behavioural Therapy, options often criticised for their low efficacy and safety. In contrast, fish-oil-based supplements comprising omega-3 polyunsaturated fatty acids and supporting nutrients are gaining recognition as safe and effective alternatives. Here we present the protocol for a randomised, double-blind, placebo-controlled trial investigating the effects of a high eicosapentaenoic acid multinutrient supplement on validated measures of anxiety and depression in healthy university students experiencing non-clinical levels of anxiety and depression. The primary outcome is improvement in anxiety compared to the placebo group assessed via the Generalised Anxiety Disorder Assessment-7 scale. The participants will be randomised to active treatment comprising a daily dose of 1125 mg eicosapentaenoic acid, 441 mg docosahexaenoic acid, 330 mg magnesium and 7.5 mg vitamin E, or placebo, for 24 weeks, and will complete validated questionnaires and tablet-based tasks sensitive to mood at baseline and end of intervention. Circulating fatty acids and key biomarkers will also be assessed. The students will be genotyped for polymorphisms thought to influence the relationship between long-chain omega-3 polyunsaturated fatty acids and affect. Trial registration; ClinicalTrials.gov, NCT04844034.

Omega-3 fatty acids are associated with blood-brain barrier integrity in a healthy aging population

In aging populations, omega-3 polyunsaturated fatty acids (PUFAs) have been associated with better cognitive function, slower rates of cognitive decline, and lower risk of developing dementia. Animal studies have shown that diets rich in omega-3 PUFAs reduce blood-brain barrier (BBB) disruption associated with aging, but this has yet to be observed in humans. Forty-five healthy subjects (mean age, 76 years) were recruited and underwent cognitive assessment (verbal learning and memory, language, processing speed, executive function, and motor control) and measurement of PUFAs. Forty of the same subjects also underwent magnetic resonance imaging (MRI) to measure BBB integrity (K_trans using dynamic contrast-enhanced MRI). The long chain omega-3 score (DHA+EPA) was negatively correlated with K_trans values in the internal capsule, indicating higher omega-3 levels were associated with greater BBB integrity in this region (r = -0.525, p = .004). Trends were observed for a positive correlation between the long chain omega-3 score and both memory and language scores, but not with executive function, speed, or motor control. The omega-6 score was not significantly correlated with any cognitive scores or K_trans values. The significant correlations between long chain omega-3 levels and BBB integrity provide a possible mechanism by which omega-3 PUFAs are associated with brain health.

The regulatory role of dietary factors in skeletal muscle development, regeneration and function

Skeletal muscle plays a crucial role in motor function, respiration, and whole-body energy homeostasis. How to regulate the development and function of skeletal muscle has become a hot research topic for improving lifestyle and extending life span. Numerous transcription factors and nutritional factors have been clarified are closely associated with the regulation of skeletal muscle development, regeneration and function. In this article, the roles of different dietary factors including green tea, quercetin, curcumin (CUR), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and resveratrol (RES) in regulating skeletal muscle development, muscle mass, muscle function, and muscle recovery have been summarized and discussed. We also reviewed the potential regulatory molecular mechanism of these factors. Based on the current findings, dietary factors may be used as a potential therapeutic agent to treat skeletal muscle dysfunction as well as its related diseases.