Effects of carotenoid supplementation on liver enzymes in adults: a GRADE-assessed systematic review and dose-response meta-analysis of randomized controlled trials.

ABSTRACT:

Background and aims

Carotenoids are known for their beneficial effects in improving chronic diseases through their antioxidant properties. However, there has been no meta-analysis on the effects of carotenoids on liver enzymes and the evidence is inconsistent. So, this study aimed to evaluate the effects of carotenoid supplementation on liver enzyme levels in adults.

Methods

Through November 2024, the PubMed, Scopus and Web of Science electronic databases were searched for eligible trials evaluating the carotenoid supplementation effects on the Alanine aminotransferase (ALT), Aspartate aminotransferase (AST), Alkaline phosphatase (ALP) and Gamma-glutamyl transferase (GGT). The 95% confidence intervals (CIs) and weighted mean differences (WMDs) were calculated using the random effects model. As part of standard methods, dose-response, meta-regressions, sensitivity, and publication bias analyses were performed. Evidence certainty was assessed using GRADE (Grading of Recommendations for Assessment, Development, and Evaluation).

Results

Of the 15 studies (20 arms; n = 757), 7 included healthy participants, while 8 involved non-healthy individuals, including 4 studies on prediabetes or diabetes. Pooled estimates indicated non-significant effects of carotenoid supplementation on all enzymes including ALT (WMD: -2.25 IU/L, 95%CI: -4.84,0.34, P = 0.089), AST (WMD: -0.46 IU/L, 95%CI: -1.25,0.34, P = 0.259), ALP (WMD: -0.34 IU/L, 95%CI: -6.89,6.21, P = 0.918) and GGT (WMD: -0.43 IU/L, 95%CI: -3.06,2.21, P = 0.751) levels non-significantly. Significant reductions in ALT levels occurred in < 12 weeks (P = 0.028), BMI ≥ 25 (P = 0.045), and among non-healthy participants (P = 0.015). AST levels were significantly reduced in non-healthy participants (P = 0.003) with ages > 50 (P = 0.003) as well as GGT levels (P = 0.011) in non-healthy participants.

Conclusion

Carotenoid supplementation might be beneficial in reducing liver enzymes, especially in non-healthy participants and in those with a BMI ≥ 25 kg/m². However, more trials with standard methods are required.

Prospero registeration code

CRD42024612956.

SUBMITTER: Heydari SS 

PROVIDER: S-EPMC12836767 | biostudies-literature | 2025 Dec

REPOSITORIES: biostudies-literature