Omega-3 Benefits: Omega-3 and Cognitive Function
Omega-3 benefits to cognitive function
Adequate intake of long-chain omega-3 polyunsaturated fatty acids (LC-PUFA) is essential for the brain to function: they increase fluidity of the neuronal membranes and some of them (mostly AA and omega-3 EPA) act as second messengers in neurotransmission systems, as well as contributing to many other aspects of neuron function.(1,2) Omega-3 DHA is involved in myelination(3) and is important in synaptic efficacy (and the speed of transmission(2)), which may increase the efficiency of information processing. The effects of Omega-3 LC-PUFAs, especially, omega-3 DHA, in visual development and perception and even dyslexia, may be related to the fact that they improve the photoreceptor function of the rods and visual acuity and ensure normal retina development in humans (5,6). These visual potentials in children may be improved with Omega-3 LC-PUFA supplements.(7) With respect to memory, animal investigations have shown that omega-3 DHA significantly affects neuron development of the hippocampus and synaptic function in the developing hippocampus:(8) in neurons supplemented with omega-3 DHA, spontaneous synaptic activity is significantly greater and DHA-deprived rat foetuses show growth and synaptogenesis inhibition in hippocampus neurons. These findings may explain the improvement in cognitive processes after omega-3 DHA supplementation and why dietary Omega-3 LC-PUFA deficiency is associated with a learning deficit.(8) The speed with which information is perceived and acquired depends to a certain extent on the presence of omega-3 DHA.(9)
Cognitive functions in children and Omega-3
Fish consumption by the mother during pregnancy results in better visual memory in recognising new things and better results in verbal or linguistic intelligence scores even after 8 years of age (10, 11). Maternal consumption of supplements with 1,200 mg of omega-3 DHA and 800 mg of EPA is associated with higher scores in standardised children’s intelligence tests (10).
Sub-optimum ingestion of fish by mothers, less than 340 mg/week, is associated with children in the bottom quartile of verbal intelligence and lower scores in pro-social behaviour, motor movements, communication and development of social skills (12).
Omega-3 LC-PUFAs may also be beneficial to children with learning difficulties and help improve reading speed in children with dyslexia (13).
Cognitive functions in adults and Omega-3
Omega-3 fatty acid supplementation (1,600 mg omega-3 EPA and 800 mg DHA/day) in adults (average age 33 years) produces an improvement in sustained attention, reduces errors in attention tests and produces improvements in reaction times measured by electromyography (EMG).(14)
Fish oil ingestion has a protective effect on age-associated cognitive deterioration in patients aged 65 years or over. Compared with people who consumed less than one portion of fish a week, who had a cognitive deterioration of –0.1 standard units/year, those who consumed one portion of fish a week had 10% less deterioration, and for those who consumed 2 or more a week the reduction was 13%.(15)
Epidemiological studies performed over the last decade have shown that people who ingest higher amounts of omega-3 DHA and EPA have a relatively lower risk of incidence and progression of dementia. People consuming an average of 400 mg of Omega-3 a day have less cognitive deterioration than those who consume an average of 20 mg/day.(16)
People with Alzheimer’s disease have a lower concentration of Omega-3 acids in their neurons. It has been suggested that dietary consumption of Omega-3 may reduce the inflammatory processes that cause the neurodegenerative changes produced in Alzheimer’s.(17)
Morris et al. found that people who consume fish once a week have a 60% lower risk of suffering from Alzheimer’s disease.(18)
In patients with Alzheimer’s disease, consumption of Omega-3 fatty acids (1,700 mg DHA and 600 mg EPA/day for 6 months) helps improve cognitive function and slow cognitive decline.(19)
Attention deficit hyperactivity disorder (ADHD) related to learning and behavioural problems and Omega-3
There is evidence that Omega-3 LC-PUFAs can help treat problems related to attention deficit hyperactivity disorder (ADHD), such as lack of attention, hyperactivity and impulsivity, although additional research is required to confirm these findings.(20)
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