In the News: Recent Omega-3 Research Findings

Omega-3 Reduces Risk of Irregular Heartbeat In Older Individuals

Atrial fibrillation (AF) is the most common type of chronic arrhythmia in adults, and the risk for AF increases considerably with age.

Animal studies and short-term clinical trials suggest that increased intake of omega-3 fatty acids might improve cardiac function by influencing blood pressure, systemic vascular resistance, and myocardial efficiency, and/or via anti-inflammatory and anti-fibrotic effects. Omega-3 may also increase electrical stability by modulating ion channels.

Although some studies have assessed the association of omega-3s with incident AF, nearly all have estimated dietary intake via dietary questionnaires – with inconsistent results. Also, prior studies have focused on predominantly middle-aged populations rather than older adults, who are most at risk.

Now, findings from the Harvard School of Public Health provide evidence that omega-3 fatty acids may also protect against onset of atrial fibrillation (AF) later in life (1). The researchers looked at circulating levels of omega-3 – a more objective and accurate measure of omega-3 intake – among 3326 participants over 65 and free of AF or heart failure at baseline.

The highest average levels of total omega-3 fatty acids as well as DHA were associated with a reduction in AF risk of about 25%. Additionally, when evaluated as percent of all fatty acids, each 1% higher level of total omega-3s was linked to a 9% lower risk of AF.

Omega-3 May Reduce Key Inflammatory Biomarker Linked to Cardiovascular Disease & Cancer Risks

Two new studies published in the American Journal of Nutrition suggest that higher intakes of omega-3s may confer both cardiac and anti-cancer benefits through decreasing levels of an inflammatory biomarker, soluble intercellular adhesion molecule-1 or sICAM-1. Accumulating evidence suggests that low circulating levels of sICAM-1 contribute to a decrease in atherosclerosis risk.

The first study (2), a meta-analysis, analyzed 18 randomized trials that involved omega-3 supplementation and provided data on sICAM-1 concentrations. Results showed that supplemental omega-3 was associated with sICAM-1 reductions in both healthy individuals and people with abnormal levels of blood lipids.

According to the researchers, the findings suggest that omega-3s reduce inflammation by selectively inhibiting monocyte activation rather than endothelial activation. Since the protective effects were observed in both healthy subjects and those with dyslipidemia, it’s possible that supplemental omega-3 may help prevent the development of atherosclerosis as well as slow its progression.

In the second study (3), a team from the National Institute of Health and Medical Research in Paris investigated whether omega-3 intakes might alter sICAM-1 concentrations and cancer risk by comparing 408 cancer cases with 760 healthy people with similar characteristics.

Levels of sICAM-1 were indeed related to omega-3 levels, and this association was seen for different types of cancer, including prostate and breast cancer. In addition, sICAM-1 was positively linked with cancer risk in people who had below average omega-3 intakes.

Two mechanisms may explain the observations. First, the omega-3s may be decreasing the expression of adhesion molecules like sICAM-1. Secondly, the omega-3s may act by intervening in the pro-cancer pathway stimulated by sICAM-1.

While more research is needed, the two studies taken together support the idea that supplemental omega-3 can reduce the biomarker sICAM-1, resulting in potential cardiovascular and anti-cancer benefits.

References

1. Wu JHY, et al. Association of plasma phospholipid long-chain omega-3 fatty acids with incident atrial fibrillation in older adults: The Cardiovascular Health Study. Circulation 125:1084-93, 2012.
2. Yang Y, et al. Effects of n-3 PUFA supplementation on plasma soluble adhesion molecules: a meta-analysis of randomized controlled trials. Am J Clin Nutr 95:972-80; Epub Feb 29, 2012.
3. Touvier M, et al. Modulation of the association between plasma intercellular adhesion molecule-1 and cancer risk by n-3 PUFA intake: a nested case-control study. Am J Clin Nutr 95:944-50; Epub Feb 29, 2012.