Four months of feeding omega-3s to old rats did not affect age-related declines in cognitive function, but the supplements did produce some “small but positive” changes to heart function, according to findings published in the Journal of Gerontology: Biological Science .
Researchers from Wake Forest University School of Medicine and University of South Dakota said that their observations “data raise the possibility that fish oil supplementation for purposes of cardiac and brain protection may need to occur earlier in the life span”.
The heart health benefits of fish oil, and the omega-3 fatty acids it contains, are well-documented, being first reported in the early 1970s by Dr Jorn Dyerberg and his co-workers in The Lancet and The American Journal of Clinical Nutrition. To date, the polyunsaturated fatty acids (PUFAs) have been linked to improvements in blood lipid levels, a reduced tendency of thrombosis, blood pressure and heart rate improvements, and improved vascular function.
“From a therapeutic perspective, it is not known if efficacious dosages of omega-3 [polyunsaturated fatty acids, or PUFAs] that improve cardiac function in aging would also be effective for improving brain function,” explained the researchers, led by Wake Forest’s Leanne Groban, MD.
“The current study was designed to explore the effects of a dietary intervention on both brain and cardiac function in the same subject using a well-established model of cognitive decline in aging,” they added.
Dr Groban and her co-workers used young and older male rats and fed them a standard diet for five or 24 months, respectively. After this time the animals were switched to an experimental diet containing approximately 1.75 mg EPA and 1.17 mg DHA per day per animal for one or four months, respectively. At the end of this period all animals were subjected to a range or tests to assess cardiovascular and cognitive function.
Results showed that the older animals did benefit from fish oil supplementation, but the benefits were limited to diastolic function, or the filling of the heart with blood following contraction (systolic).
The younger animals had better spatial memory than the older animals, and the fish oil supplements were not associated with any reversal of the age-related memory deficits or increases in inflammation in the brain, wrote the researchers.
“Future studies are needed to address the hypothesis that supplementation may need to occur prior to the accumulation of inflammatory damage to be effective in brain, and almost certainly in the heart,” they wrote.
“If the hypothesis were proven correct, it would indicate that supplementation is beneficial when used preventatively but ineffective at reversing damage if begun late in the life span after chronic inflammation has been established.”
Source: Journal of Gerontology: Biological Science
2011; Volume 66A, Issue 5, Pages 521-533, doi:10.1093/gerona/glr017
“Dietary Fish Oil Modestly Attenuates the Effect of Age on Diastolic Function but Has No Effect on Memory or Brain Inflammation in Aged Rats”
Authors: S. Sergeant, J.A. McQuail, D.R. Riddle, F.H. Chilton, S.B. Ortmeier, J.A. Jessup, L. Groban, M.M. Nicolle