Efficacy and safety of dietary polyphenol supplementation in the treatment of non-alcoholic fatty liver disease: A systematic review and meta-analysis

Abstract

BackgroundDietary polyphenol treatment of non-alcoholic fatty liver disease (NAFLD) is a novel direction, and the existing clinical studies have little effective evidence for its therapeutic effect, and some studies have inconsistent results. The effectiveness of dietary polyphenols in the treatment of NAFLD is still controversial. The aim of this study was to evaluate the therapeutic efficacy of oral dietary polyphenols in patients with NAFLD.MethodsThe literature (both Chinese and English) published before 30 April 2022 in PubMed, Cochrane, Medline, CNKI, and other databases on the treatment of NAFLD with dietary polyphenols was searched. Manual screening, quality assessment, and data extraction of search results were conducted strictly according to the inclusion and exclusion criteria. RevMan 5.3 software was used to perform the meta-analysis.ResultsThe RCTs included in this study involved dietary supplementation with eight polyphenols (curcumin, resveratrol, naringenin, anthocyanin, hesperidin, catechin, silymarin, and genistein) and 2,173 participants. This systematic review and meta-analysis found that 1) curcumin may decrease body mass index (BMI), Aspartate aminotransferase (AST), Alanine aminotransferase (ALT), Triglycerides (TG) total cholesterol (TC), and Homeostasis Model Assessment-Insulin Resistance (HOMA-IR) compared to placebo; and curcumin does not increase the occurrence of adverse events. 2) Although the meta-analysis results of all randomized controlled trials (RCTs) did not reveal significant positive changes, individual RCTs showed meaningful results. 3) Naringenin significantly decreased the percentage of NAFLD grade, TG, TC, and low-density lipoprotein cholesterol (LDL-C) and increased high-density lipoprotein cholesterol (HDL-C) but had no significant effect on AST and ALT, and it is a safe supplementation. 4) Only one team presents a protocol about anthocyanin (from Cornus mas L. fruit extract) in the treatment of NAFLD. 5) Hesperidin may decrease BMI, AST, ALT, TG, TC, HOMA-IR, and so on. 6) Catechin may decrease BMI, HOMA-IR, and TG level, and it was well tolerated by the patients. 7) Silymarin was effective in improving ALT and AST and reducing hepatic fat accumulation and liver stiffness in NAFLD patients.ConclusionBased on current evidence, curcumin can reduce BMI, TG, TC, liver enzymes, and insulin resistance; catechin can reduce BMI, insulin resistance, and TG effectively; silymarin can reduce liver enzymes. For resveratrol, naringenin, anthocyanin, hesperidin, and catechin, more RCTs are needed to further evaluate their efficacy and safety.

Association between flavonoid and subclasses intake and metabolic associated fatty liver disease in U.S. adults: Results from National Health and Nutrition Examination Survey 2017–2018

“…Daily intake of 1,500 mg curcumin could reduce serum cholesterol, glucose, and ALT in patients with NAFLD ( 40 ). A study of systematic review and meta-analysis showed that curcumin, naringenin, hesperidin, catechin, and silymarin may have therapeutic efficacy in patients with NAFLD ( 41 ). The result of our study on anthocyanins is complementary to the research on the correlation between polyphenols and MAFLD.…”

Efficacy and Safety of Pentoxifylline on Patients with Non-Alcoholic Steatohepatitis; Randomized Controlled Trial

“…The control group, NASH patients, perceived regular treatment (silymarin, omega 3, and vitamin E) [25,26]. In the treated group, NASH patients received regular treatment plus PTX (400 mg 3 times daily) after meals for 6 months, following the approval of the Ethical Committee and obtained informed consent from recruited subjects.…”

Effects of curcumin/turmeric supplementation on the liver enzymes, lipid profiles, glycemic index, and anthropometric indices in non‐alcoholic fatty liver patients: An umbrella meta‐analysis

“…According to the results of included studies' quality assessment by the AMSTAR2 questionnaire (Table S3), three cases of included studies were of high quality and eight cases were of moderate quality. However, three studies (Fakhri et al, 2022;Mansour-Ghanaei et al, 2019;Yang et al, 2022) did not assess the presence and likely impact of publication bias because of the low number of included studies. Moreover, using the GRADE system, all quality effects were rated as moderate (Table 3).…”

“…The duration of curcumin supplementation ranged from 4 to 24 weeks. The location of the studies was as follows: six in Iran (Baziar & Parohan, 2020;Fakhri et al, 2022;Goodarzi et al, 2019;Jafarirad et al, 2019;Jalali et al, 2020;Mansour-Ghanaei et al, 2019), three in China (Wei et al, 2019;Yang et al, 2022;Zhou et al, 2021), one in Australia (Khalili & Nammi, 2022), and one case in Malaysia (Ngu et al, 2022). As shown in Table 2, all of the included meta-analyses evaluated the quality of their included randomized controlled trials using Cochrane (10 cases) and Jaded scales (one case) and reported a good quality for their included studies.…”