Abstract
Coffee is rich in phenolic acids, such as caffeic acid and chlorogenic acid (CGA). Polyphenol-rich diets were shown to reduce the risk of metabolic syndrome (MeTS). Background and Objectives: This systematic review and meta-analysis discusses the effects of coffee consumption and its dose-response on MeTS parameters. Materials and Methods: PubMed and Scopus® were searched for relevant articles published between 2015 and 2020. This review focused on randomised controlled trials (RCTs) investigating the effect of coffee consumption on anthropometric measurements, glycaemic indices, lipid profiles, and blood pressure. Data from relevant studies were extracted and analysed using random, fixed, or pooled effects models with 95% confidence intervals (CIs). Results: Green coffee extract (GCE) supplementation (180 to 376 mg) was found to reduce waist circumference (weighted mean difference (WMD) = −0.39; 95% CI: −0.68, −0.10), triglyceride levels (WMD = −0.27; 95% CI: −0.43, −0.10), high−density lipoprotein−cholesterol levels (WMD = 0.62; 95% CI: 0.34, 0.90), systolic blood pressure (WMD = −0.44; 95% CI: −0.57, −0.32), and diastolic blood pressure (WMD = −0.83; 95% CI: −1.40, −0.26). Decaffeinated coffee (510.6 mg) reduced fasting blood glucose levels (WMD = −0.81; 95% CI: −1.65, 0.03). The meta-analysis showed that the intake of GCE containing 180 to 376 mg of CGA (administered in a capsule) and liquid decaffeinated coffee containing 510.6 mg of CGA improved the MeTS outcomes in study participants. Conclusions: The findings of the review suggested that the effect of coffee on MeTS parameters varies depending on the types and doses of coffee administered. A more detailed RCT on specific coffee doses (with adjustment for energy and polyphenol intake) and physical activity is needed to further confirm the observed outcomes.
Highlights
Metabolic syndrome (MeTS) is a cluster of complex metabolic disorders [1] characterised by the presence of any three of the following five medical conditions: abdominal obesity, high serum triglyceride (TG) levels, low high-density lipoprotein cholesterol (HDLc) levels, elevated blood pressure, and elevated fasting blood glucose (FBG) levels [2]
Green coffee extract (GCE) containing 180 mg of chlorogenic acid (CGA) showed the greatest effect size (d = 1.40, 95% confidence intervals (CIs): 1.11, 1.69), followed by that containing 376 mg of CGA, 1000 mg of CGE (CGA dose not specified), 250 mg of CGA, 250 mg of CGA, and 372 mg of CGA
Fourteen high-quality randomised controlled trials (RCTs) were included in this review, and the observation period in the studies ranged from 60 min to 24 weeks; the longer study periods were adequate for evaluating substantial changes in the metabolic syndrome (MeTS) parameters
Summary
Metabolic syndrome (MeTS) is a cluster of complex metabolic disorders [1] characterised by the presence of any three of the following five medical conditions: abdominal obesity, high serum triglyceride (TG) levels, low high-density lipoprotein cholesterol (HDLc) levels, elevated blood pressure, and elevated fasting blood glucose (FBG) levels [2]. The global prevalence of MeTS is approximately 3.3% (range, 0%–19.2%), with a prevalence of 11.9% (range, 2.8%–29.3%) in children with obesity and 29.2% (range, 10%–66%) in adults with obesity [3]. 12%–37% and 12%–26% of the population in Asia and Europe, respectively, are affected by MeTS [4]. Genetic and lifestyle-related factors, such as alcohol intake, smoking, sedentary habits, and poor dietary habits, such as intake of sugar-sweetened beverages, were identified as risk factors in MeTS development. Coffee (Coffea spp., Coffea arabica, Coffea robusta, and Coffea liberica) is one of the most popular beverages worldwide, with an estimated consumption of 500 billion cups per year [5]. Bioactive compounds in coffee, such as chlorogenic acid (CGA), caffeine, niacin, and magnesium, may play a role in reducing the risk of type 2 diabetes mellitus (T2DM)
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