EPA and DHA in cognitive impairment, emotional dysfunction and cerebral atrophy
Age-related cognitive impairment is characterised by progressive and irreversible loss of grey matter in various regions of the brain, together with atrophy of the hippocampus and the prefrontal lobes. The omega-3 long-chain polyunsaturated fatty acids (LG-PUFA) docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA) and docosapentaenoic acid (DPA) are key components of neuron membranes and crucial modulators of neuroinflammation, oxidative stress and neurogenesis; thus they are considered to have a neuroprotective effect on ageing brains.
Longitudinal studies in humans have found that high omega-3 LC-PUFA consumption is associated with better cognitive function, lower risk of dementia, larger grey matter volume and less white matter hyperintensity. However, results have also been published that are inconsistent with these observations, which could be due to faults in study design, such as a lack of control of factors including socio-economic status, genetics, habits and lifestyle. In this context, studies on animal models could provide the methodological control for the variables involved.
Cutuli D. et al. recently carried out a study on a murine model, after another by same authors in which aged mice supplemented with omega-3 LC-PUFA showed better hippocampal-dependent mnesic function, together with greater cellular plasticity and less neurodegeneration. On this occasion, the investigators studied the effect of eight weeks’ supplementation with omega-3 LC-PUFA on cognitive aspects (spacial and social discrimination), emotional aspects (anxiety and stress response capacity) and the volume of grey matter by regions. With respect to their life cycle, the mice were aged.
After the tests, the omega-3-supplemented mice showed:
- Better memory.
- Greater response capacity to stress and no modification to anxiety levels.
- Larger volumes of grey matter in the cortex and hippocampus.
- Greater post-mortem brain concentrations of omega-3 LC-PUFA.
- The cognitive and behavioural improvements correlated positively with the volume of frontal-hippocampal grey matter and post-mortem cerebral concentrations of EPA and DHA.
- Post-mortem cerebral EPA and DHA concentrations correlated positively to the volume of frontal-hippocampal grey matter.
These results would corroborate the protective function of omega-3 LC-PUFA supplementation in cognitive impairment, emotional dysfunction and cerebral atrophy, even when supplementation is started in old age.
Cutuli D, Pagani M, Caporali P et al. Effects of Omega-3 Fatty Acid Supplementation on Cognitive Functions and Neural Substrates: A Voxel-Based Morphometry Study in Aged Mice. Front Aging Neurosci. 2016 Mar 4;8:38. doi: 10.3389/fnagi.2016.00038. eCollection 2016.