J Nutr Health.  2014 Aug;47(4):236-246. 10.4163/jnh.2014.47.4.236.

The effect of walnut (Juglans regia L.) intake on improvement of blood lipid levels and vascular health: A meta-analysis

• Kwak JS
• Park MY
• Kwon O

• KMID: 2327157
• DOI: http://doi.org/10.4163/jnh.2014.47.4.236

Abstract

PURPOSE
Walnut is known to have unique favorable fatty acids, phytochemicals, and other nutrient profiles. As a result, there has been growing interest in evaluation of its health benefit related to cardiovascular disease (CVD). Although inverse associations of nut consumption and risk factors of cardiovascular disease have been reported in many epidemiological studies and qualitative reviews, few meta-analysis studies have been reported. This meta-analysis was conducted in order to evaluate the effect of a walnut-enhanced diet on CVD risk factors.
METHODS
We searched Pubmed, Cochrane, Science Direct, and KISS (Korean studies Information Service System) through July 2014. A random-effects meta-analysis was conducted on 17 trials reporting total cholesterol (TC), 14 trials reporting LDL cholesterol (LDL-C), 15 trials reporting HDL cholesterol (HDL-C), 17 trials reporting triglyceride (TG), and four trials reporting flow-mediated dilation (FMD).
RESULTS
In meta-analysis, intake of a walnut-enhanced diet resulted in significantly lowered TC, LDL-C, and TG by -0.124 mmol/l (95% CI, -0.209, -0.039; p = 0.004), -0.085 mmol/lL (95% CI, -0.167, -0.004; p = l0.039), and -0.080 mmol/l (95% CI, -0.155, -0.004; p = 0.039), respectively. The overall pooled estimate of the effect on FMD was +1.313% (95% CI, 0.744, 1.882, p = 0.000). HDL-C was not affected by walnut intake. No statistical heterogeneity was observed for any analysis. Results of funnel plots and Egger's regression suggested a low likelihood of publication bias in all biomarkers (p > 0.05).
CONCLUSION
Findings of this meta-analysis provide consistent evidence that walnut-enhanced diet intake reduces the CVD risk factors.

Keyword

Meta-analysis; walnut; Juglans regia; blood lipid level; flow-mediated dilation

MeSH Terms

Biomarkers
Cardiovascular Diseases
Cholesterol
Cholesterol, HDL
Cholesterol, LDL
Diet
Fatty Acids
Information Services
Insurance Benefits
Juglans*
Nuts
Phytochemicals
Population Characteristics
Publication Bias
Risk Factors
Triglycerides
Cholesterol
Cholesterol, HDL
Cholesterol, LDL
Fatty Acids

Figure

• 

  Fig. 1 Flow diagram of included and excluded studies.

• 

  Fig. 2 Forest plot results of the effect of walnut intake on A: total cholesterol, B: LDL-cholesterol, C: HDL-cholesterol, D: Triglyceride, E: Flow-mediated dilation.

• 

  Fig. 3 Funnel plot showing the effect of the walnut intake on changes in A: Total cholesterol, B: LDL-cholesterol, C: HDL-cholesterol, D: Triglyceride, E: Flow-mediated dilation.

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