Abstract
n-3 PUFA may exert favourable effects on several processes that may inhibit the atherosclerotic process. However, the role of n-3 PUFA in lowering the risk of atherosclerotic CVD (ASCVD) has been fiercely debated. In the present paper, we summarise the main findings from previous follow-up studies of intake and studies using adipose tissue as an objective biomarker to investigate exposure to n-3 PUFA in relation to ASCVD risk and discuss some perspectives for further research. The majority of previous studies investigating intake of marine- and plant-based n-3 PUFA have focused on CHD while other ASCVD such as ischaemic stroke and peripheral artery disease have been less studied. However, recent data from Danish Diet, Cancer and Health cohort suggest that marine n-3 PUFA may be inversely associated with risk of myocardial infarction, ischaemic stroke and peripheral arterial disease caused by atherosclerosis. The effect of the plant-derived n-3 PUFA α-linolenic acid on ASCVD is less clear and several gaps in the literature remain to be explored.
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Key Points
Atherosclerosis is the underlying disease process that may result in atherosclerotic CVD (ASCVD) including myocardial infarction, ischaemic stroke and peripheral arterial disease (PAD). The typical intake of n-3 PUFA in adults varies substantially by country, but most Western populations consume approximately 0·5 to 2·3 g/d ALA and 0·1 to 0·6 g/d EPA + DHA. ALA has been ascribed anti-inflammatory, antiatherosclerotic and anti-thrombotic effects, but controversy remains whether these suggested mechanisms of action can be attributed to the effects of ALA or its role as a precursor for LC n-3 PUFA and beyond. n-3 PUFA in adipose tissue is believed to represent the long-term exposure during the previous 1–2 years and is considered the gold standard biomarker to investigate the role of n-3 PUFA in relation to chronic diseases such as ASCVD. This paper assesses the main findings from previous follow-up studies of intake and studies using adipose tissue as an objective biomarker to investigate exposure to n-3 PUFA in relation to ASCVD risk. Follow-up studies indicate that intake of LC n-3 PUFA derived mainly from seafood may be inversely associated with the risk of myocardial infarction, ischaemic stroke caused by atherosclerosis and PAD, whereas the role of plant-derived n-3 PUFA ALA in ASCVD is less clear with conflicting results reported.
Endogenous conversion of ALA may contribute to tissue levels of LC n-3 PUFA, predominantly EPA, although the significance of this is not clear because high intakes of linoleic acid relative to ALA in most Western populations may favour conversion of linoleic acid over ALA due to metabolism by shared enzymes. In summary, prospective studies using estimated intakes or adipose tissue content of marine and the plant-derived n-3 PUFA have contributed with important knowledge on the role of these PUFA in relation to development of ASCVD, but according to the authors, several gaps in the literature remains to be elucidated.