Marine Omega-3 PUFAs Improve Arterial Elasticity in 2 Months
With aging and vascular disease, arterial elasticity diminishes, bringing with it increased risk of hypertension, stroke and cardiovascular mortality. The consumption of omega-3 polyunsaturated fatty acids (n-3 PUFAs), both long-chain docosahexaenoic acid (DHA) and medium-chain alpha-linolenic acid, has modest blood pressure-lowering effects, but there is limited information about their effects on arterial elasticity. In a preliminary study, 1.8 g eicosapentaenoic acid (EPA) daily for one year was associated with a slight decrease in pulse wave velocity compared with a significant increase in this measure in the control group. Pulse wave velocity uses ultrasound waves to assess the speed of blood in determining the elasticity of the artery walls. More rigid blood vessels hasten the pulse wave, while a slower velocity reflects greater arterial elasticity. In another study of more than 500 elderly men with hyperlipidemia who consumed 2.4 g n-3 LC-PUFAs daily for 3 years, arterial elasticity measured increased significantly, i.e., pulse wave velocity decreased compared with the control participants.
In the study reported here, Dr. S. Wang and colleagues of Xi’an Jiaotong University in China, used pulse wave velocity to assess arterial elasticity in 43 overweight Chinese patients with hypertension who consumed fish oil or placebo supplements for 8 weeks. Daily n-3 LC-PUFA supplementation provided 900 mg/day of n-3 LC-PUFAs from salmon oil, containing 540 mg EPA and 360 mg DHA. Participants had a body mass index of ≥23 and systolic blood pressure ≥140 with diastolic pressure ≥90. Blood pressure control medications were suspended for 2 weeks prior to the study. Measures of pulse wave velocity, plasma lipids and blood pressure were obtained at baseline and after 56 days.
After 8 weeks of fish oil supplementation, there was a significant 21% increase in arterial elasticity, but no changes in the placebo group. Heart rate, systolic and diastolic blood pressures, plasma lipids and soluble vascular adhesion molecule-1 did not change significantly in either group during the study. As expected, n-3 PUFAs in serum fatty acids increased significantly only in the fish oil group, mainly at the expense of monounsaturated fatty acids.
The primary outcome in this study was a significant increase in arterial elasticity with the consumption of 900 mg/day of n-3 LC-PUFAs for 8 weeks. This change occurred despite the lack of change in blood pressure. Large artery elasticity has a genetic component, but is also blood pressure dependent, with decreased elasticity occurring at high blood pressure. However, hypertension triggers arterial hypertrophy, which reduces arterial stiffness. It is noteworthy that a significant reduction in arterial stiffness occurred in a relatively short time, 8 weeks, with a dose of n-3 LC-PUFAs that has been linked to reduced cardiovascular mortality in survivors of myocardial infarction. These results strengthen previous findings of improved arterial compliance with the consumption of n-3 LC-PUFAs, suggesting another way in which these fatty acids protect heart health.
SOURCE: PUFA Newsletter