A high level of long-chain omega-3 polyunsaturated fatty acids (PUFAs) in blood may lower the risk of small infarcts and other brain abnormalities that are linked to cognitive decline in the elderly, according to new research.
The study, published in the Journal of the American Heart Association, investigated the association between plasma phospholipid omega‐3 PUFAs - an objective biomarkers of exposure - and subclinical brain abnormalities on magnetic resonance imaging (MRI). Previous research has linked higher dietary intake of certain fish a reduction in such subclinical brain abnormalities - that can cause loss of thinking skills, and are associated with increased risk of dementia and stroke.
Led by Professor Jyrki Virtanen from the University of Eastern Finland, the analysed data from more than 2,000 elderly people that were followed for five years - finding that those who had a high serum omega-3 status were had around a 40% lower risk of small brain infarcts compared to those with low content.
The study also found that people who had a high omega-3 status also had fewer changes in the white matter in their brains over the five year period.
"Among older men and women, plasma phospholipid long‐chain omega‐3 PUFAs, and in particular DHA, were associated with specific findings consistent with better brain health, including lower risk of prevalent subclinical (lacunar) infarcts, better white matter grade, and lower risk of worsening white matter," wrote Virtanen and his colleagues.
"Our results support the need for additional prospective observational studies using fatty acid biomarkers, as well as randomised intervention studies to evaluate the role of omega‐3 PUFAs in subclinical brain health and disease later in life," they added - noting that the potential role of intermediate‐chain omega‐3s such as plant‐based ALA 'is less evident.'
Virtanen and his team analysed data from the Cardiovascular Health Study in the USA. In this study 3,660 people aged 65 and older underwent brain scans to detect so called silent brain infarcts, or small lesions in the brain that can cause loss of thinking skills, dementia and stroke, in addition to having blood samples taken. Further scans were performed again five years later on 2,313 of the participants.
All MRIs were centrally read by neuroradiologists in a standardised, blinded manner, said the authors - who also noted that participants with recognised transient ischemic attacks or stroke were excluded.
After multivariable adjustment, the odds ratio for having a prevalent subclinical infarct was were found to be 40% lower for those with the highest omega-3 status when compared to those with the lowest levels.
Higher long‐chain omega‐3 PUFA content was also associated with better white matter grade, but not with sulcal or ventricular grades, markers of brain atrophy, or with incident subclinical infarcts, they revealed.
"Our findings in these older men and women suggest that circulating long‐chain omega‐3 PUFA concentrations, a biomarker of regular fish consumption, are associated with lower risk and could be beneficial for the prevention of certain subclinical brain abnormalities that are commonly observed in the elderly," said Virtanen and his colleagues.
Source: Journal of the American Heart Association
Published online ahead of print, doi: 10.1161/JAHA.113.000305
"Circulating Omega‐3 Polyunsaturated Fatty Acids and Subclinical Brain Abnormalities on MRI in Older Adults: The Cardiovascular Health Study"
Authors: Jyrki K. Virtanen , David S. Siscovick , Rozenn N. Lemaitre , et al