Lipid profile and glucose changes after supplementation with astaxanthin: a systematic review and meta-analysis of randomized controlled trials

Abstract

Introduction: Many studies have shown that oral supplementation with astaxanthin may be a novel potential treatment for inflammation and oxidative stress in cardiovascular diseases, but evidence of the effects on lipid profile and glucose is still inconclusive. Therefore, we performed a meta-analysis to evaluate the efficacy of astaxanthin supplementation on plasma lipid and glucose concentrations.

Material and methods: The search included PubMed, Cochrane Library, Scopus, and EMBASE (up to November 27, 2014) to identify randomized controlled trials (RCTs) investigating the effects of astaxanthin supplementation on lipid profile and glucose levels. Two independent reviewers extracted data on study characteristics, methods and outcomes.

Results: Seven studies meeting inclusion criteria with 280 participants were selected for this meta-analysis; 163 participants were allocated to the astaxanthin supplementation group and 117 to the control group. A random-effect meta-analysis of data from 7 RCTs (10 treatment arms) did not show any significant effect of supplementation with astaxanthin on plasma concentrations of total cholesterol (weighted mean difference (WMD): -1.52 mg/dl, 95% CI: -8.69 to -5.66, p = 0.679), LDL-C (WMD: +1.25 mg/dl, 95% CI: -6.70 to +9.21, p = 0.758), HDL-C (WMD: +1.75 mg/dl, 95% CI: -0.92 to +4.42, p = 0.199), triglycerides (WMD: -4.76 mg/dl, 95% CI: -21.52 to +12.00, p = 0.578), or glucose (WMD: -2.65 mg/dl, 95% CI: -5.84 to +0.54, p = 0.103). All these effect sizes were robust, and omission of any of the included studies did not significantly change the overall estimate.

Conclusions: This meta-analysis of data from 10 RCT arms did not indicate a significant effect of supplementation with astaxanthin on plasma lipid profile, but a slight glucose-lowering effect was observed. Further, well-designed trials are necessary to validate these results.

Keywords: antioxidants; astaxanthin; glucose; lipids.

Figure 1

Flow diagram of the study selection procedure showing the number of eligible randomized controlled trials for the meta-analysis of the impact of astaxanthin supplementation on plasma lipid concentrations

Figure 2

Plots showing the risk of bias of the included trials according to Cochrane quality assessment tool

Figure 3

Forest plot detailing weighted mean difference and 95% confidence intervals for the impact of astaxanthin supplementation on plasma total cholesterol concentrations (upper graph). Leave-one-out sensitivity analysis is shown in the lower graph

Figure 4

Forest plot detailing weighted mean difference and 95% confidence intervals for the impact of astaxanthin supplementation on plasma LDL-C concentrations. Leave-one-out sensitivity analysis is shown in the lower graph

Figure 5

Forest plot detailing weighted mean difference and 95% confidence intervals for the impact of astaxanthin supplementation on plasma HDL-C concentrations. Leave-one-out sensitivity analysis is shown in the lower graph

Figure 6

Forest plot detailing weighted mean difference and 95% confidence intervals for the impact of astaxanthin supplementation on plasma triglyceride concentrations. Leave-one-out sensitivity analysis is shown in the lower graph

Figure 7

Forest plot detailing weighted mean difference and 95% confidence intervals for the impact of astaxanthin supplementation on plasma glucose concentrations. Leave-one-out sensitivity analysis is shown in the lower graph

Figure 8

Meta-regression plots of the association between mean changes in plasma lipids and glucose concentrations and administered astaxanthin dose. The size of each circle is inversely proportional to the variance of change.

Figure 9

Funnel plots detailing publication bias in the studies selected for analysis. Trim and fill method was used to impute for potentially missing studies. Open circles represent observed published studies; closed circles represent imputed unpublished studies