Written by Angeline A. De Leon, Staff Writer. Study demonstrates that a higher Omega-3 Index is associated with statistically significant, clinically relevant lower systolic and diastolic blood pressure levels in young and healthy individuals with blood pressure values within normal limits.
Reports suggest that, alarmingly, the prevalence of hypertension (high blood pressure) is on the rise, not only in older adults 1, but in healthy young adults and even athletes 2. Omega-3 polyunsaturated fatty acids (n-3 PUFAs) found in fish oils play a beneficial role in cardiovascular disease (CVD) 3, demonstrating antithrombotic (reducing blood clots) activity 4, anti-inflammatory effects 5, and the ability to improve endothelial function and even heart rate variability 6,7. By directly modulating cardiac ion channel functions in blood vessels, n-3 PUFAs can improve vasodilatory function and arterial compliance 8,9. Meta-analytic studies suggest that at higher doses, n-3 PUFAs can also lower blood pressure (BP) in hypertensive patients 10. In a 2007 observational study of over 2,000 adults with a pre-existing cardiovascular condition, researchers reported an inverse association between total dietary intake of n-3 PUFAS and BP 11. To confirm whether this inverse link between omega-3 index and BP levels is also true for healthy young adults, researchers at the University of Zurich (2018) examined whole blood n-3 PUFA levels in relation to BP in a large population of younger CVD-free individuals 12.
A total of 2036 healthy (excluded for presence of CVD, diabetes, or a BMI greater than 35 kg/m2) young adults (aged 25-41 years) were enrolled in a cross-sectional, cohort-based study. Venous whole blood samples were collected following an overnight fast and measured for fatty acid (FAs) composition using gas chromatography, with relative amounts of eicosapentaenoic acid (EPA) and docosahexaenoic (DHA) expressed as a percentage of a total of 26 FAs (Omega-3 Index). Researchers measured conventional office BP (following at least 5 minutes of sitting time) and ambulatory BP during a 24-hour period (once every 15 minutes between 7:30 am and 10:00 pm and every 30 minutes during the remaining time within 24 hours).
Analyses showed that with increasing Omega-3 Index, all BP indices decreased linearly. Relative to subjects in the lowest Omega-3 Index quartile, those in the highest quartile showed a 4 and 2-mmHg lower 24-hr systolic BP (SBP) and diastolic BP (DBP), respectively (p < 0.01). After adjusting for confounding variables, SBP, DBP, and 24-h BP remained inversely associated with Omega-3 Index. Per 1-U increase in log-transformed Omega-3 Index multivariable adjusted β coefficients were: -2.66 (95% Confidence Interval: -4.83 to –0.51, p = 0.02) for 24-h SBP, -2.30 (95% CI: -3.92 to –0.68, p = 0.005) for 24-h DBP, -2.81 (95% CI: -5.22 to –0.40, p = 0.02) for conventional SBP, and –1.86 (95% CI: -3.68 to –0.04, p = 0.05) for conventional DBP. DHA also showed inverse associations with all BP indices, except for night-time SBP and conventional DBP.
Study findings support the hypothesis that the inverse link between omega-3 fatty acid concentrations and blood pressure is as true for healthy young adults, as it is for the older adult population. Consistent across all measured parameters (for conventional BP as well as 24-h BP), a linear inverse association was evident for CVD-free individuals aged 25-41 years. Researchers conclude that regular omega-3 dietary intake can play an effective preventative role against hypertension, which is becoming increasingly prevalent in today’s younger adult population (2). Due to the cross-sectional nature of the current study, a direct causal relationship between Omega-3 levels and BP cannot be established. Another potential weakness of the study is the lack of data on the source of n-3 PUFAs and documentation of subjects taking supplements. It would be valuable for future trials to examine how these and other dietary and lifestyle factors might influence the relationship between Omega-3 Index and BP levels.
Source: Filipovic MG, Aeschbacher S, Reiner MF, et al. Whole blood omega-3 fatty acid concentrations are inversely associated with blood pressure in young, healthy adults. J Hypertens. 2018; 36: 1548-1554. DOI: 10.1097/HJH. 0000000000001728.
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Posted August 26, 2019.
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- Filipovic MG, Aeschbacher S, Reiner MF, et al. Whole blood omega-3 fatty acid concentrations are inversely associated with blood pressure in young, healthy adults. Journal of hypertension. 2018;36(7):1548.