Marine n-3 Fatty Acids, Sudden Cardiac Death, and Ischemic Heart Disease: Fish or Supplements?

Intake of marine and plant-derived n-3 fatty acids and development of atherosclerotic cardiovascular disease in the Danish Diet, Cancer and Health cohort

PURPOSE

The objective of this study was to investigate the association between intake of seafood and plant-derived n-3 polyunsaturated fatty acids (PUFA) and development of total atherosclerotic cardiovascular disease (ASCVD) and acute major ischemic events.

METHODS

A total of 53,909 men and women were enrolled between 1993 and 1997 into the Danish Diet, Cancer and Health cohort and followed through nationwide Danish registries for development of total ASCVD defined as a first registration of myocardial infarction, peripheral artery disease, or ischemic stroke due to large artery atherosclerosis or small-vessel occlusion. At recruitment, the intake of the major marine n-3 PUFA, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and the plant-derived n-3 PUFA, alpha-linolenic acid (ALA), was assessed using a validated food frequency questionnaire. Statistical analyses were conducted using sex-stratified multivariable Cox proportional hazard regression models.

RESULTS

During a median of 13.5 years of follow-up, 3958 participants developed ASCVD including 3270 patients with an acute major ischemic event. In multivariable analyses including adjustment for established risk factors, we found no associations for intake of ALA, but indications of inverse associations between intake of EPA, DHA and EPA + DHA and the rate of total ASCVD and acute major ischemic events.

CONCLUSIONS

A high intake of marine n-3 PUFA was associated with a lower risk of total ASCVD and acute major ischemic events, whereas no association could be demonstrated for the plant-derived ALA.

Do omega-3 fatty acids increase risk of atrial fibrillation?

PURPOSE OF THE REVIEW

To summarize the findings from recent observational follow-up studies and randomized trials of plant- and marine omega-3 fatty acids on the risk of atrial fibrillation (AF).

RECENT FINDINGS

Recent randomized cardiovascular outcome trials have indicated that supplements with marine omega-3 fatty acids may be associated with a higher risk of AF, and a meta-analysis has suggested that marine omega-3 fatty acid supplements were associated with a 25% higher relative risk of AF. Also, a recent large observational study reported a modest higher risk of AF in habitual users of marine omega-3 fatty acid supplements. However, recent observational biomarker studies of circulating and adipose tissue content of marine omega-3 fatty acids have in contrast reported a lower risk of AF. Very limited knowledge exists on the role of plant-derived omega-3 fatty acids and AF.

SUMMARY

Marine omega-3 fatty acid supplements may increase the risk of AF, whereas biomarkers reflecting consumption of marine omega-3 fatty acids have been linked to a lower risk of AF. Clinicians should inform patients that marine omega-3 fatty acid supplement may increase AF risk, and this should be taking into account when discussing pros and cons of taking supplements with marine omega-3 fatty acids.

Diet and Sudden Death: How to Reduce the Risk

In addition to the association of dietary patterns, specific foods and nutrients with several diseases, including cardiovascular disease and mortality, there is also strong emerging evidence of an association of dietary patterns with the risk of sudden cardiac death (SCD). In this comprehensive review, data are presented and analyzed about foods and diets that mitigate the risk of ventricular arrhythmias (VAs) and SCD, but also about arrhythmogenic nutritional elements and patterns that seem to enhance or facilitate potentially malignant VAs and SCD. The antiarrhythmic or protective group comprises fish, nuts and other foods enriched in omega-3 polyunsaturated fatty acids, the Mediterranean and other healthy diets, vitamins E, A and D and certain minerals (magnesium, potassium, selenium). The arrhythmogenic-food group includes saturated fat, trans fats, ketogenic and liquid protein diets, the Southern and other unhealthy diets, energy drinks and excessive caffeine intake, as well as heavy alcohol drinking. Relevant antiarrhythmic mechanisms include modification of cell membrane structure by n-3 polyunsaturated fatty acids, their direct effect on calcium channels and cardiomyocytes and their important role in eicosanoid metabolism, enhancing myocyte electric stability, reducing vulnerability to VAs, lowering heart rate, and improving heart rate variability, each of which is a risk factor for SCD. Contrarily, saturated fat causes calcium handling abnormalities and calcium overload in cardiomyocytes, while a high-fat diet causes mitochondrial dysfunction that dysregulates a variety of ion channels promoting VAs and SCD. Free fatty acids have been considered proarrhythmic and implicated in facilitating SCD; thus, diets increasing free fatty acids, e.g., ketogenic diets, should be discouraged and replaced with diets enriched with polyunsaturated fatty acids, which can also reduce free fatty acids. All available relevant data on this important topic are herein reviewed, large studies and meta-analyses and pertinent advisories are tabulated, while protective (antiarrhythmic) and arrhythmogenic specific diet constituents are pictorially illustrated.