Omega-3 fatty acids support mood and prevent dementia

Experiencing an excess of negative emotions such as anxiety, anger, sadness, and worry is also referred to as neuroticism. Research indicates that neuroticism is associated with low levels of the omega-3 fatty acid DHA, which over time may increase the risk of vascular dementia. This emerges from a large population study, where the authors highlight the particular importance of omega-3 fatty acids for the brain, nervous system, and circulatory system. Overall, ensuring adequate omega-3 intake appears beneficial for both mood and cognitive function.

Neuroticism is a personality trait characterized by a heightened tendency to experience negative emotions such as anxiety, fear, worry, anger, sadness, shame, and guilt - especially in response to stress. These traits are thought to underlie certain psychiatric disorders and cardiovascular diseases. Previous population studies have revealed that a higher tendency toward neuroticism is linked to an increased risk of dementia, particularly vascular dementia, which results from disruptions in the brain’s blood supply or blood vessels. Neuroticism is also associated with the marker named WMH (white matter hyperintensities), which indicates damage to cerebral blood vessels.
Overall, neuroticism may be connected to an unhealthy lifestyle, chronic inflammation, and gut microbiome imbalances, all of which can affect various metabolic processes. Disrupted metabolic processes such as insulin resistance, elevated hemoglobin A1c (long-term blood sugar), and high lipid levels (cholesterol and triglycerides) are known to increase the risk of cardiovascular disease. Similarly, omega-3 deficiency - particularly of DHA - is linked to impaired circulation and cognitive function.
The new study aimed to examine the relationship between blood levels of the omega-3 fatty acid DHA, neuroticism, and the risk of developing dementia. Using data from the UK Biobank, a large British population study conducted from 2006–2010, researchers collected information from over 215,000 participants aged 40–69, none of whom had dementia at baseline. Blood samples collected from 2007-2010 were analyzed for a wide range of metabolites and markers, including different cholesterol types (VLDL, LDL, HDL), lipids, fatty acids, amino acids, and hemoglobin A1c.
Participants’ levels of neuroticism were assessed using a questionnaire with a score ranging from 0-12, where 12 indicated the highest tendency toward neuroticism. The development of different types of dementia, including vascular dementia and Alzheimer’s disease, was tracked using hospital records and diagnoses, while controlling for confounding factors such as sex, age, ethnicity, education, smoking, alcohol consumption, BMI, and medication.
The study found that neuroticism was associated with 119 of the 249 metabolites analyzed. Of these, five were involved in fatty acid metabolism, which directly connects to neuroticism and the risk of developing any type of dementia. Factors particularly associated with a lower risk of neuroticism and dementia included:

• The omega-3 fatty acid DHA (docosahexaenoic acid)
• A higher proportion of DHA relative to total fatty acids
• A higher proportion of omega-3 fatty acids (including DHA and EPA) relative to total fatty acids
• The ratio of omega-3 to omega-6

The researchers conclude that neuroticism is linked to lower blood levels of omega-3 fatty acids, especially DHA. This suggests that neuroticism itself may lead to lower DHA levels, which in turn increases the risk of dementia, particularly vascular dementia. The association with Alzheimer’s disease was less pronounced. The study, published in the Journal of Affective Disorders, also indicates that individuals with neuroticism may have a greater need for DHA. Increased intake of omega-3 from fatty fish or fish oil supplements may help prevent vascular dementia.

• It is estimated that 86% of the global population does not get enough omega-3 from their diet.

Sources of different omega-3 fatty acids

Fatty fish, cod liver, and shellfish provide the two omega-3 forms DHA and EPA. DHA is important for cognitive function, while EPA helps reduce inflammation. Both DHA and EPA support heart and circulatory health. Positive health effects have been observed with a daily intake of 250 mg DHA, which can be obtained from a serving of e.g., herring or a fish oil supplement. Some individuals may require higher amounts.
Certain plant sources such as flaxseed oil, walnuts, rapeseed oil, and chia seeds contain the omega-3 form ALA. However, many people have difficulty converting ALA into the biologically active forms DHA and EPA.

The important balance between omega-3 and omega-6

Omega-3 and omega-6 fatty acids are found in cell membranes, where they regulate numerous metabolic processes. A proper balance between these fatty acids is crucial for healthy metabolism. Modern diets, however, often contain too little omega-3 from fatty fish and too much omega-6 from seed oils, margarine, mayonnaise, fries, dressings, processed foods, and other industrially processed products. This imbalance increases the risk of chronic inflammation, oxidative stress, and other metabolic disturbances. Many people gain health benefits by increasing omega-3 intake and reducing omega-6 intake.

References:

Yaqing Gao et al. Neuroticism, omega-3 fatty acids, and risk of dementia. Journal of Affective Disorders. 2025

Timothy H Ciesielski. Global Access to Uncontaminated Omega-3 Polyunsaturated Fatty Acids Requires Attention. AJPM Focus. 2025