Abstract
Ischemic stroke is a major cause of death and morbidity worldwide. It has been suggested that polyunsaturated fatty acids (PUFAs) may be associated with a lower risk ischemic stroke, but this has been far less studied than their role for coronary heart disease. In this paper, we summarize the main findings from previous follow-up studies investigating associations between intake or biomarkers of the major PUFAs including alpha-linolenic acid (ALA), marine n-3 PUFAs and linoleic acid (LA) and the development of ischemic stroke. Several follow-up studies have suggested that marine n-3 PUFAs may be associated with a lower risk of ischemic stroke although results have not been consistent and limited knowledge exist on the individual marine n-3 PUFAs and ischemic stroke and its subtypes. The role of ALA is less clear, but most studies have not supported that ALA is appreciably associated with ischemic stroke risk. Some studies have supported that LA might be associated with a lower risk of total ischemic stroke, while limited evidence exist on PUFAs and ischemic stroke subtypes. The associations may depend on the macronutrients that PUFAs replace and this substitution aspect together with focus on dietary patterns represent interesting areas for future research.
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Key Points
Ischemic stroke is characterized by an episode of neurological dysfunction attributed to cerebral infarction in the perfusion territory of an stenosed or occluded artery. Several studies have suggested that LC n-3 PUFAs and LA may be associated with a lower risk of coronary heart disease (CHD). CHD and ischemic stroke may share pathophysiological similarities, less is known about the role of PUFAs in relation to risk of ischemic stroke and previous studies have not yielded consistent results.
The objective of this paper was to summarize the main findings from previous follow-up studies investigating associations between intake or biomarkers of exposure of the major PUFAs (ALA, LC n-3 PUFAs, and LA) and ischemic stroke.
The authors indicate that new studies have investigated the association between ALA intake and ischemic stroke. Dietary intake of ALA has been reported to be inversely associated with the rate of total ischemic stroke among Dutch men and women. Indications of a lower rate of total ischemic stroke were observed when comparing the highest quintile of ALA intake with the lowest, but no consistent pattern of association was observed across quintiles of ALA in this cohort of US men and women. They suggest that limited knowledge is available regarding the associations between ALA intake and the risk of ischemic stroke subtypes but no appreciable pattern of associations were observed between intake of ALA and the rate of ischemic stroke subtypes caused by large artery atherosclerosis, small vessel-occlusion or cardioembolism in the DCH cohort.
The findings from previous follow-up and nested-case control studies using biomarkers of ALA to investigate associations with ischemic stroke have not been conclusive. Limited data are available on biomarkers of ALA and ischemic stroke subtypes. However, data from some cohorts suggested a statistically significant U-shaped association between ALA content in adipose tissue and the rate of ischemic stroke due to large artery atherosclerosis with the lowest rate observed around the median content of ALA in adipose tissue.
In summary, previous studies evaluating either intake of ALA or content of ALA in blood components or adipose tissue have shown conflicting results, but most studies does not support that ALA exposure is inversely associated with ischemic stroke risk.