DHA but not EPA lowers Ambulatory Blood Pressure

Objective

Earlier animal studies have reported that the 2 major omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), might have differential effects on blood pressure BP and heart rate (HR).

This particular study was conducted to assess the differences in the effects of EPA or DHA on ambulatory (BP) and HR in humans.

Study population

57 men and women, 21-80 years of age, with fasting HDL levels of ≤ 44 mg/dl (in men) and ≤ 54 mg/dl (in women).

Study design

A double-blind, placebo-controlled parallel design trial

Length of study

6 weeks

Intervention

4 g/day of DHA, EPA or placebo respectively

Results

• DHA therapy significantly reduced the 24-hour and daytime (awake) ambulatory BP (p<0.05).
• The 24 h and daytime BP values were found to be reduced by 5.8/3.3.
• DHA supplementation reduced 24-h heart rate (HR), daytime HR and nighttime HR by 3. 5±0.8 bpm, 3.7±1.2 bpm, and 2. 8±1.2, respectively.
• The EPA supplementation did not show any significance in controlling ambulatory BP or HR.

Conclusion

DHA is the principal omega-3 fatty acid and is associated with significant reductions in ambulatory blood pressure and heart rate. Thus, these results indicate the important implications of DHA for human nutrition and the food industry.

Source

Maki KC, et al. Lipid responses to a dietary docosahexaenoic acid supplement in men and women with below average levels of high density lipoprotein cholesterol. J Am Coll Nutr. 2005; 24(3):189-199.

Algal DHA Significantly Reduces the Lipid and Triglyceride levels

Objective

The aim of the study was to assess fasting lipid responses to DHA supplement in men and women with below-average levels of high-density lipoprotein (HDL) cholesterol.

Study design

A randomized, double-blind, controlled clinical trial.

Number of subjects

57 men and women with fasting HDL levels of ≤ 44 mg/dl (in men) and ≤ 54 mg/dl (in women) were enrolled into the study.

Study intervention

The subjects were randomized to receive 1.52 g/day DHA from DHA rich algal triglycerides or olive oil as a control respectively.

Duration of the study

The study was carried out for a period of 6 weeks.

Results

• DHA supplement showed a significant change in the triglyceride levels, total and low density cholesterol levels in comparison with placebo [-43(DHA) vs. -14 (controls) mg/dL, p=0.015], [12 vs. 3 mg/dL; p=0.021] and [17 vs. 3 mg/dL; p=0.001], respectively.
• Furthermore the percentage changes were also found to be significantly higher in DHA group in comparison to the placebo group and [-21%(DHA) vs. -7% (controls), p=0.009] in triglycerides, total [6% vs. 2%; p=0.018] and low-density lipoprotein [12% vs. 3%; p=0.001] cholesterol concentrations
• The triglyceride to HDL cholesterol ratio [-1.33 vs. -0.50, p=0.010], also significantly reduced in DHA supplemented group in comparison to the control group.
• A significant reduction in the percentage of LDL cholesterol carried by small, dense particles was found in the DHA supplemented group (changes =-10% vs. -3%, p=0.025) in comparison to the placebo group.

• DHA supplementation significantly reduces trigly- ceride level and triglyceride/HDL cholesterol ratio

Conclusion

In patients with below-average HDL cholesterol concentrations, supplementation with DHA raised the LDL cholesterol level but showed favorable effects on triglycerides, the triglyceride/HDL cholesterol ratio and the fraction of LDL cholesterol carried by small, dense particles.

Source

Maki KC, Van Elswyk ME, McCarthy D, et al. Lipid responses to a dietary docosahexaenoic acid supplement in men and women with below average levels of high-density lipoprotein cholesterol. J Am Coll Nutr. 2005;24(3):189-199.

DHA Leads to Significant Reduction in Deaths from Cardiac Causes

Objective

The primary objective of this systemic review was to assess the effects of DHA and EPA on mortality and arrhythmias and to explore dose response and formulation effects.

Number of subjects

32779 patients from total of 12 randomized, controlled trials were enrolled into the review.

Death due to cardiac causes was evaluated in 11 studies involving 32519 patients and showed a significant 20% decrease in events

Results

• The analysis of the data revealed that a neutral effect was found in 3 studies (n =1148) for appropriate implantable cardiac defibrillator intervention (odds ratio {OR} 0.90, 95% CI 0.55-1.46) and in 6 studies (n =31 111) for sudden cardiac death (0.81, 0.52 to 1.25).
•  Furthermore, a total of 11 studies (n =32,439 and n =32,519) showed that the DHA /EPA offered a significant reduction in all-cause mortality (0.92, 0.82 to 1.03) and in deaths from cardiac causes (0.80, 0.69 to 0.92).
•  The analysis of the dose-response relation for DHA and EPA on reduction in deaths from cardiac causes was found to be non-significant.

Conclusion

The supplementation with DHA/EPA was associated with a significant reduction in deaths from cardiac causes however, had no effect on arrhythmias or all-cause mortality.

Source

Leon H, Shibata MC, Sivakumaran S, et al. Effect of fish oil on arrhythmias and mortality: systematic review. BMJ. 2008;337:a2931. Published online 2008 December 23.

Blood omega-3 Fatty Acid levels were inversely associated with Total Mortality

Objective

Several studies found that the consumption and blood levels of omega-3 fatty acids are inversely associated with the risk for sudden cardiac death. However, their relationship with all-cause mortality was unclear.

The aim of the study was to assess the association between baseline blood omega-3 FA levels and reduced risk for all-cause mortality in patients with stable coronary heart disease (CHD).

Study design

The Heart and Soul study is a prospective cohort design study with a median follow-up of 5.9 years.

Number of subjects

A total of 956 patients were enrolled into the study.

Results

• In comparison to the patients with baseline EPA+DHA levels below the median (<3.6%), the patients with higher ≥ 3.6% had a 27% decreased risk of death [Hazard Ratio {HR} 0.73, 95% CI 0.56-0.94].
•  Furthermore, this association was unchanged by adjustment for age, sex, ethnicity, center, socioeconomic status, traditional cardiovascular risk factors, and inflammatory markers (HR 0.74, 95% CI 0.55-1.00, p<0.05).

In patients with stable CHD, higher baseline blood levels of DHA+EPA were associated with increased survival time

Conclusion

The significant blood levels of blood omega-3 FA levels were inversely associated with total mortality and were independent of standard and emerging risk factors in outpatients with stable CHD. Thus these results suggested that the decreased tissue omega-3 FA levels might adversely impact metabolism.

Source

Pottala JV, Garg S, Cohen BE, et al. Blood EPA and DHA Independently Predict All-Cause Mortality in Patients with Stable Coronary Heart Disease. The Heart and Soul Study. Circ Cardiovasc Qual Outcomes. 2010;3(4):406–412.