Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Meta-Analysis
. 2022 Oct 23;14(21):4460.
doi: 10.3390/nu14214460.

The Effect of Walnut Intake on Lipids: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Saeed Mastour Alshahrani  1 , Reham M Mashat  2 , Diaa Almutairi  3 , Alaa Mathkour  4 , Sahar Saad Alqahtani  1 , Amirah Alasmari  4 , Abdullah Hassan Alzahrani  4 , Reem Ayed  5 , Mohammed Yahya Asiri  4 , Alsanussi Elsherif  6 , Abdullah Alsabaani  7
Affiliations
Meta-Analysis

The Effect of Walnut Intake on Lipids: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Saeed Mastour Alshahrani et al. Nutrients. .

Abstract

Cardiovascular diseases (CVD) are the leading causes of death worldwide. Dyslipidemia is a cardiometabolic risk factor of CVD, yet it can be modifiable. Walnuts have been suggested as a dietary intervention to improve the lipid profile. Therefore, we reviewed the literature to assess the evidence linking walnut intake to the improvement of blood lipids, including total cholesterol (TC), low-density lipoprotein (LDL-C) cholesterol, high-density lipoprotein (HDL-C) cholesterol, and triglycerides (TG). PubMed and Embase databases were searched from 2010 up to March 2022. We limited our search to randomized controlled trials conducted on humans and published in English during the specified period. Cochrane's risk of bias tool for interventional studies was used. A random-effects model was used for the meta-analysis, and weighted mean differences were obtained (WMD) Thirteen trials from the U.S., Europe, and Asia were included. Walnut intake was associated with significant reductions in TC (WMD: -8.58 mg/dL), LDL-C (WMD: -5.68 mg/dL), and TG (WMD: -10.94 mg/dL). Walnut consumption was not associated with HDL-C. Subgroup analysis showed that overweight/obese and those with comorbidities had more lipid improvement. A longer trial duration did result in further improvements. However, our results may be prone to bias due to extraneous confounding factors. Additionally, levels of heterogeneity were considerable for some outcomes of interest. Results from this meta-analysis provide evidence for the health benefits of walnuts on blood lipids. Walnuts possibly reduce the risk of CVD; thus, they can be successfully added to a dietary pattern to enhance health benefits.

Keywords: dyslipidemia; low density lipoprotein cholesterol (LDL-C); meta-analysis; randomized controlled trials; total cholesterol (TC); triglyceride (TG); walnuts.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
PRISMA flowchart of study selection process for the meta-analysis.
Figure 2
Figure 2
Quality assessment of included studies according to Cochrane risk of bias tool.
Figure 3
Figure 3
Forest plot presenting mean difference (MD) and 95% confidence intervals for the effect of walnut consumption on (A) TC (mg/dL), (B) LDL−C (mg/dL), (C) HDL−C (mg/dL), and (D) TG (mg/dL) [34,35,36,37,38,39,40,41,42,43,44,45,46].
Figure 3
Figure 3
Forest plot presenting mean difference (MD) and 95% confidence intervals for the effect of walnut consumption on (A) TC (mg/dL), (B) LDL−C (mg/dL), (C) HDL−C (mg/dL), and (D) TG (mg/dL) [34,35,36,37,38,39,40,41,42,43,44,45,46].
See this image and copyright information in PMC

References

    1. Finegold J.A., Asaria P., Francis D.P. Mortality from ischaemic heart disease by country, region, and age: Statistics from World Health Organisation and United Nations. Int. J. Cardiol. 2013;168:934–945. doi: 10.1016/j.ijcard.2012.10.046. - DOI - PMC - PubMed
    1. Dahlöf B. Cardiovascular disease risk factors: Epidemiology and risk assessment. Am. J. Cardiol. 2010;105:3A–9A. doi: 10.1016/j.amjcard.2009.10.007. - DOI - PubMed
    1. Cannon C.P. Cardiovascular disease and modifiable cardiometabolic risk factors. Clin. Cornerstone. 2007;8:11–28. doi: 10.1016/S1098-3597(07)80025-1. - DOI - PubMed
    1. Ginsberg H.N., Zhang Y.-L., Hernandez-Ono A. Metabolic syndrome: Focus on dyslipidemia. Obesity. 2006;14:41S. doi: 10.1038/oby.2006.281. - DOI - PubMed
    1. Ponce O.J., Larrea-Mantilla L., Hemmingsen B., Serrano V., Rodriguez-Gutierrez R., Spencer-Bonilla G., Alvarez-Villalobos N., Benkhadra K., Haddad A., Gionfriddo M.R. Lipid-lowering agents in older individuals: A systematic review and meta-analysis of randomized clinical trials. J. Clin. Endocrinol. Metab. 2019;104:1585–1594. doi: 10.1210/jc.2019-00195. - DOI - PubMed

LinkOut - more resources