Coffee Consumption and Non-alcoholic Fatty Liver Disease: An Umbrella Review and a Systematic Review and Meta-analysis

Abstract

Background: The effects of coffee consumption on hepatic outcomes are controversial. This study investigated the associations between coffee consumption and the incidence of non-alcoholic fatty liver disease (NAFLD) in the general population and the reduction of liver fibrosis among patients with NAFLD.Methods: The study consisted of two parts: an umbrella review and a systematic review and meta-analysis (SRMA). The searches for each part were performed separately using PubMed, EMBASE, Cochrane, Scopus, and CINAHL databases. All articles published up to September 2021 were reviewed. To be eligible, studies for the umbrella review were required to report outcomes that compared the risks of NAFLD in the general population and/or liver fibrosis in patients with NAFLD who did and did not drink coffee. Our SRMA included primary studies reporting the effects of coffee consumption on NAFLD-related outcomes. The outcomes were pooled using a random-effects model and reported in both qualitative and quantitative terms (pooled risk ratio, odds ratio, and weighted mean difference).Results: We identified four published SRMAs during the umbrella review. Most studies showed that individuals in the general population who regularly drank coffee were significantly associated with a lower NAFLD incidence than those who did not. Our SRMA included nine studies on the effects of coffee consumption on NAFLD incidence. Pooled data from 147,875 subjects showed that coffee consumption was not associated with a lower NAFLD incidence in the general population. The between-study heterogeneity was high (I2, 72–85%). Interestingly, among patients with NAFLD (5 studies; n = 3,752), coffee consumption was significantly associated with a reduction in liver fibrosis (odds ratio, 0.67; 95% CI, 0.55 to 0.80; I2, 3%). There were no differences in the coffee consumption of the general population and of those with NAFLD (4 studies; n = 19,482) or by patients with no/mild liver fibrosis and those with significant fibrosis (4 studies; n = 3,331).Conclusions: There are contrasting results on the effects of coffee on NAFLD prevention in the general population. Benefits of coffee consumption on liver fibrosis were seen among patients with NAFLD.Systematic Review Registration: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021226607, identifier CRD42021226607

Crosstalk between dietary patterns, obesity and nonalcoholic fatty liver disease

“…NAFLD patients who drink three to four cups of coffee per day will have more health benefits than harm, with the reduction in risk for various health outcome[ 109 ]. Nevertheless, a recent meta-analysis of 11 epidemiological studies confirmed association with regular coffee consumption and decreased risk of NAFLD[ 110 ].…”

“…It was noted that decaffeinated coffee has the same helpful effect on NAFLD[ 114 ]. It was considered that two cups of coffee/day helped in the prevention of hepatocellular carcinoma[ 115 ], while three cups of coffee/day prevented steatohepatitis and fibrosis[ 109 ]. As observations have so far been based on epidemiological studies, future clinical studies need to confirm whether coffee consumption can be considered a preventative factor for NAFLD.…”

Increased Intake of Both Caffeine and Non-Caffeine Coffee Components Is Associated with Reduced NAFLD Severity in Subjects with Type 2 Diabetes

“…Anty et al found that regular coffee, but not espresso, was protective against fibrosis in a group of morbidly obese European women [ 34 ]. Recent meta-analyses show a consensus that coffee intake protects against fibrosis for subjects with NAFLD [ 6 , 39 , 40 , 41 , 42 , 43 ], but there is a lack of agreement on whether coffee intake has any effect on NAFLD incidence in the general population, with three of these studies supporting an effect [ 40 , 42 , 43 ] and the other three concluding that there is no effect [ 6 , 39 , 41 ]. Our study found a significantly higher level of caffeine metabolites in subjects without fibrosis compared to those with fibrosis ( Figure 3 ), but failed to find significant correlation between coffee metabolites and fibrosis, when studied as a continuous variable ( Table 2 ).…”

Extrahepatic morbidities and mortality of NAFLD: an umbrella review of meta‐analyses

“…An umbrella review is an increasing popular approach that systematic collects and evaluates information from systematic reviews and meta-analyses, which is used to consolidate the highest level of evidence on a given topic (usually clinical associations), and inform clinical practice as well as public health policies. 8 Previously, several umbrella reviews related to NAFLD have been published to summarise the quality of evidence regarding the associations between nutritional, lifestyle, metabolic factors and NAFLD, [9][10][11] and effects of sodium glucose co-transporter 2 (SLGT2) 12 and resveratrol supplementation 13 in patients with NAFLD. However, no umbrella review was conducted for issue of the extra-hepatic morbidities and mortality of NAFLD currently.…”