Feeding old rats with omega-3s for four months had no effect on age-related decline in cognitive function, but the supplements produced some “small but positive” changes in heart function, according to results published in the Journal of Gerontology: Biological Science.
Researchers at Wake Forest University School of Medicine and the University of South Dakota said their observations “data increase the possibility that fish oil supplementation may need to be earlier in life for heart and brain protection purposes”.
The heart health benefits of fish oil and the omega-3 fatty acids it contains are well documented and were first discovered in the early 1970s by Dr. Jorn Dyerberg and his coworkers reported in The Lancet and The American Journal of Clinical Nutrition. So far, polyunsaturated fatty acids (PUFAs) have been associated with improvements in blood lipid levels, a reduced tendency to thrombosis, improvements in blood pressure and heart rate, and improved vascular function.
“From a therapeutic point of view, it is not known whether an effective dosage of omega-3 is available [polyunsaturated fatty acids, or PUFAs] This improvement in heart function as we age would also be effective in improving brain function, ”explained the researchers, led by Leanne Groban, MD of Wake Forest.
“The current study was designed to examine the effects of dietary intervention on brain and heart function in the same subject using a well-established model of cognitive decline in aging,” they added.
Dr. Groban and her coworkers used young and older male rats and fed them a standard diet for five and 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. At the end of this period, all animals were subjected to a range or tests to assess cardiovascular and cognitive function.
The results showed that the older animals benefited from a fish oil supplement, but the benefits were limited to diastolic function or filling the heart with blood after a contraction (systolic).
The younger animals had better spatial memory than the older animals, and the fish oil supplements were not linked to reversing age-related memory deficits or increasing inflammation in the brain, the researchers wrote.
“Future studies are needed to address the hypothesis that supplementation may need to be done prior to the accumulation of inflammatory damage in order to be effective in the brain and almost certainly in the heart,” they wrote.
“If the hypothesis turns out to be correct, it would indicate that supplementation is beneficial when used preventively but is ineffective in reversing damage if started late in the life span after chronic inflammation is established.”
Source: Journal of Gerontology: Biological Science
2011; Volume 66A, issue 5, pages 521-533, doi: 10.1093 / gerona / glr017
“Dietary fish oil modestly mitigates the effects of age on diastolic function, but has no effect on memory or encephalitis in aged rats.”
Authors: S. Sergeant, JA McQuail, DR Riddle, FH Chilton, SB Ortmeier, JA Jessup, L. Groban, MM Nicolle