Arachidonic acid and cognitive function in the elderly

ResearchBlogging.org

Arachidonic acid.  The very word makes most nutritionists cringe.  Many of us are taught to avoid it like the plague.  Americans have developed an egg-phobia because of it (the misinterpretations of egg research will be reviewed in a later post).   How can something that biochemically competes with our beloved omega 3s be good for us?  Like many topics, oversimplification and acceptance of observational research seems to have led us astray.

In a recent study (1) by Ishikura et al. studied the effects of Arachidonic acid (AA) enriched triglyceride on elderly men.  They selected 25 healthy Japanese men of average age 62.77 +/- 2.87 years.  In a crossover design, subjects in the AA group received 600mg/day of AA enriched triglyceride  (contains 240mg AA) for 1 month, while the other group received olive oil.  With a 1 month washout period between, the groups then switched regimens for 1 month.

ERPs (Event-Related Potentials- a non-invasive method to evaluate neurophysiological disturbances associated with ageing and neurodegenerative disorders) were recorded before and after administration periods, and blood collected for hematological and biochemical parameters.  The P300 component of ERPs was tested in this case- P300 latency (reflects changes in neural activity in development and ageing) is positively correlated with ageing in human adults, and P300 amplitude decreases with age.

Fatty acid content of phospholipids in serum were analyzed before and after administration periods.

The results showed that AA content in serum phospholipids increased in the AA group but not the olive oil group.  DHA content in serum phospholipids was unchanged in both groups.  All physical characteristics, hematological and biochemical parameters unchanged in both groups.

In the AA group, P300 latency was shortened, and P300 amplitude was increased, suggesting an improvement of age related declines in cognitive function and learning ability.

Another study suggests that AA may contribute to trigger synaptogenesis, possibly explaining the results of the study.

Importance

The authors highlight the previous research that shows a lower AA content in membrane phospholipids in aged animals when compared to young ones.  In these models, with ageing spatial cognition and learning ability are decreased as well as AA and DHA content of cerebral phospholipids, and recovery of abilities occurs with addition of AA and DHA.

AA is an essential fatty acid in breast milk and required for infant brain development, but this is the first study to show an improvement in cognitive impairment with AA alone in (healthy) human adults.  The authors mention some of the DHA and donepezil (AChE inhibitor)  research as some of the only other treatments for reversing cognitive decline.

The authors announce the following:

“We plan to  examine  the  effects  of  ARA-enriched  triglyceride,  a safe food without adverse drug reactions, on mild cognitive  impairment  or  dementia  due  to  Alzheimer’s  disease”

AA is found mostly in meats, eggs, and fish, and average estimated intake on a Western like diet is 50mg-300mg per day.

In elderly adults who may have difficulty eating these foods because of trouble chewing, swallowing, or preparing, this is a promising simple supplemental addition that may slow cognitive decline with ageing.

We plan
to  examine  the  effects  of  ARA-enriched  triglyceride,  a
safe food without adverse drug reactions, on mild cogni-
tive  impairment  or  dementia  due  to  Alzheimer’s  dis-
ease

References

Ishikura Y, Ikeda G, Akimoto K, Hata M, Kusumoto A, Kidokoro A, Kontani M, Kawashima H, Kiso Y, & Koga Y (2009). Arachidonic Acid Supplementation Decreases P300 Latency and Increases P300 Amplitude of Event-Related Potentials in Healthy Elderly Men. Neuropsychobiology, 60 (2), 73-79 PMID: 19752581