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. 2021 May 13;9(7):3563-3572.
doi: 10.1002/fsn3.2309. eCollection 2021 Jul.

Effect of onion on blood lipid profile: A meta-analysis of randomized controlled trials

Wang Huang  1 , Gang Tang  1 , Linyu Zhang  2 , Jie Tao  2 , Zhengqiang Wei  1
Affiliations

Effect of onion on blood lipid profile: A meta-analysis of randomized controlled trials

Wang Huang et al. Food Sci Nutr. .

Abstract

Background: Studies indicate that onion supplementation may be effective in the treatment of dyslipidemia; however, the results remain controversial. This meta-analysis was conducted to evaluate potential benefits of onion on lipid profile.

Methods: Up to 12 October 2020, PubMed, Cochrane Library, Web of Science, and Scopus were searched for randomized controlled trials evaluating the effects of onion on lipid profile. Mean differences (MD) and 95% confidence intervals (CI) were calculated. Meta-analysis was conducted using the fixed-effects model.

Results: Ten trials with 446 participants in total were included in the meta-analysis. The pooled findings of 10 studies suggested that onion supplementation significantly improved high-density lipoprotein cholesterol (HDL) (MD: 2.29 mg/dl; 95% CI: 0.87, 3.72; I 2 = 0%) and low-density lipoprotein cholesterol (LDL) (MD: -6.64 mg/dl; 95% CI: -10.91, -2.36; I 2 = 32%),while onion supplementation did not significantly lower triglycerides (TG) (MD: -6.55 mg/dl; 95% CI: -15.64, 2.53; I 2 = 45%). Analysis of nine trials showed a significant reduction in total cholesterol (TC) (MD: -5.39 mg/dl; 95% CI: -10.68, -0.09; I 2 = 49%) in patients with onion supplementation compared to the control group.

Conclusion: In summary, supplementation of onion was beneficial to control dyslipidemia, including improving levels of HDL, LDL, and TC, but could not reduce TG level. The therapeutic benefits of onion for dyslipidemia need to be treated with caution considering that some of the results are not robust.

Keywords: cholesterol; lipid profiles; meta‐analysis; onion; triglycerides.

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Conflict of interest statement

The authors declare that they do not have any conflict of interest.

Figures

FIGURE. 1
FIGURE. 1
PRISMA flow diagram of the literature retrieval process
FIGURE. 2
FIGURE. 2
Risk of bias for each included study. (a) risk of bias summary; (b) risk of bias graph
FIGURE. 3
FIGURE. 3
Forest plots of the effect of onion on plasma high‐density lipoprotein cholesterol concentrations
FIGURE. 4
FIGURE. 4
Forest plots of the effect of onion on plasma low‐density lipoprotein cholesterol concentrations
FIGURE. 5
FIGURE. 5
Forest plots of the effect of onion on plasma triglycerides concentrations
FIGURE. 6
FIGURE. 6
Forest plots of the effect of onion on plasma total cholesterol concentrations
See this image and copyright information in PMC

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