The effect of green-coffee extract supplementation on obesity: A systematic review and dose-response meta-analysis of randomized controlled trials

Impact of coffee and its bioactive compounds on the risks of type 2 diabetes and its complications: A comprehensive review

BACKGROUND

Coffee beans have a long history of use as traditional medicine by various indigenous people. Recent focus has been given to the health benefits of coffee beans and its bioactive compounds. Research on the bioactivities, applications, and effects of processing methods on coffee beans' phytochemical composition and activities has been conducted extensively. The current review attempts to provide an update on the biological effects of coffee on type 2 diabetes (T2D) and its comorbidities.

METHODS

Comprehensive literature search was carried out on peer-reviewed published data on biological activities of coffee on in vitro, in vivo and epidemiological research results published from January 2015 to December 2022, using online databases such as PubMed, Google Scholar and ScienceDirect for our searches.

RESULTS

The main findings were: firstly, coffee may contribute to the prevention of oxidative stress and T2D-related illnesses such as cardiovascular disease, retinopathy, obesity, and metabolic syndrome; secondly, consuming up to 400 mg/day (1-4 cups per day) of coffee is associated with lower risks of T2D; thirdly, caffeine consumed between 0.5 and 4 h before a meal may inhibit acute metabolic rate; and finally, both caffeinated and decaffeinated coffee are associated with reducing the risks of T2D.

CONCLUSION

Available evidence indicates that long-term consumption of coffee is associated with decreased risk of T2D and its complications as well as decreased body weight. This has been attributed to the consumption of coffee with the abundance of bioactive chemicals.

Polyphenols in obesity and weight management: Are they worth further research? An umbrella review

Polyphenols are widely known for their putative antioxidant and anti-inflammatory effects and their potential protective role in several diseases such as type 2 diabetes, cardiovascular disease and cancer. They have also attracted significant interest as 'anti-obesity' agents, although with mechanisms of action that have been exclusively demonstrated in animal and in vitro studies. This umbrella review aims to evaluate current evidence surrounding the role of polyphenols in obesity and weight management and to establish the usefulness of these agents in combatting obesity. A search of systematic reviews and meta-analyses of randomised controlled trials was carried out. Nine systematic reviews (of which eight included a meta-analysis) were included. Evidence of polyphenols' effects on reducing bodyweight is mixed, and where the effects are significant, they are numerically small and unlikely to be of help in reducing bodyweight or preventing weight gain. Future research should focus on establishing the anti-inflammatory and antioxidant effects of polyphenols through well-designed randomised controlled trials. Such research could be more valuable and cost-effective since it has shown potential to improve human health.

Chlorogenic acid in green bean coffee on body weight: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Supplemental green bean coffee extract (GBCE) with caffeine has been shown to prevent weight gain. There are different dosages of GBCE that contain chlorogenic acid (CGA), and the data for their effectiveness in preventing weight gain (500 mg/day) is currently out of date. To better understand the effects of GBCE containing CGA on body weight, the present study sets out to perform a systematic review and meta-analysis of these studies.

METHODS

Using electronic databases, including Scopus, Embase, PubMed, and Cochrane Library databases, literature was searched up to October 13, 2022. For the meta-analysis examining the impact of GBCE containing CGA (500 mg/day) on body weight with a random-effects model, the randomized controlled trials (RCTs) were considered. We calculated weighted mean differences and 95% confidence intervals (CIs). To gauge study heterogeneity, the Cochran Q statistic and I-squared tests (I2) were employed.

RESULTS

The meta-analysis includes three RCTs with 103 individuals (case = 51, control = 52). The combined findings of GBCE with CGA at least 500 mg/day result in body weight reduction (WMD: - 1.30 and 95% CI: - 2.07 to - 0.52, p = 0.001) without study heterogeneity (I2 = 0%, p = 0.904) and without publication bias estimated using Egger's and Begger's test (p = 0.752 and p = 0.602, respectively).

CONCLUSIONS

According to the meta-analysis, GBCE with CGA 500 mg/day lowers body weight. Nevertheless, despite its limited sample size and short-term study, this study was successful. Long-term research on the effectiveness and safety of GBCE and CGA on body weight require more clinical trials.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42021254916.

Weight Loss Supplements

Being overweight or obese can predispose people to chronic diseases and metabolic disorders such as cardiovascular illnesses, diabetes, Alzheimer's disease, and cancer, which are costly public health problems and leading causes of mortality worldwide. Many people hope to solve this problem by using food supplements, as they can be self-prescribed, contain molecules of natural origin considered to be incapable of causing damage to health, and the only sacrifice they require is economic. The market offers supplements containing food plant-derived molecules (e.g., primary and secondary metabolites, vitamins, and fibers), microbes (probiotics), and microbial-derived fractions (postbiotics). They can control lipid and carbohydrate metabolism, reduce appetite (interacting with the central nervous system) and adipogenesis, influence intestinal microbiota activity, and increase energy expenditure. Unfortunately, the copious choice of products and different legislation on food supplements worldwide can confuse consumers. This review summarizes the activity and toxicity of dietary supplements for weight control to clarify their potentiality and adverse reactions. A lack of research regarding commercially available supplements has been noted. Supplements containing postbiotic moieties are of particular interest. They are easier to store and transport and are safe even for people with a deficient immune system.

The effect of green tea supplementation on the anthropometric outcomes in overweight and obese women: a time and dose-response meta-analysis of randomized controlled trials

Inconsistencies are evident within the literature regarding the role of Green Tea (GT) supplementation on women living with obesity. To address this, we conducted to determine the impact of GT supplementation on the weight, body mass index (BMI), and waist circumference (WC) in overweight and obese women using time and dose-response meta-analysis of randomized controlled trials (RCTs). This meta-analysis searched electronic Scopus, Web of Science, Embase, and PubMed/Medline databases from inception to December 1^st, 2022. Data were reported as weighted mean difference (WMD) with 95% confidence interval (CI). A total of 2061 references were identified, and 15 articles with 16 RCT arms on body weight, 17 RCT arms on BMI, and 7 RCT arms on WC were included in the meta-analysis. GT supplementation significantly decreases body weight (WMD: -1.23 kg, 95% CI: -2.13 to -0.33, p = 0.007), BMI (WMD: -0.47 kg/m², 95% CI: -0.87 to -0.07, p = 0.020) and WC (WMD: -3.46 cm, 95% CI: -6.75 to -0.16, p = 0.040). In subgroup analyses, GT consumption demonstrated lowered body weight with dosaes ≥1000 mg/day (WMD: -1.38 kg), in the RCTs, which lasted ≥8 wk (WMD: -1.24 kg). The non-linear dose-response assessment detected a negative correlation between the changes in body weight and BMI in green tea consumption of more than 1000 (mg/day). The GT supplementation reduced the weight, BMI, and WC in overweight and obese women. In clinical practice, healthcare professionals can recommend using GT with dosages ≥ 1000mg/day and duration ≥ 8 wk in obese women.

Coffee consumption, health benefits and side effects: a narrative review and update for dietitians and nutritionists

Coffee is one of the most popular beverages worldwide; however, its impact on health outcomes and adverse effects is not fully understood. The current review aims to establish an update about the benefits of coffee consumption on health outcomes highlighting its side effects, and finally coming up with an attempt to provide some recommendations on its doses. A literature review using the PubMed/Medline database was carried out and the data were summarized by applying a narrative approach using the available evidence based on the literature. The main findings were the following: first, coffee may contribute to the prevention of inflammatory and oxidative stress-related diseases, such as obesity, metabolic syndrome and type 2 diabetes; second, coffee consumption seems to be associated with a lower incidence of several types of cancer and with a reduction in the risk of all-cause mortality; finally, the consumption of up to 400 mg/day (1-4 cups per day) of caffeine is safe. However, the time gap between coffee consumption and some drugs should be taken into account in order to avoid interaction. However, most of the data were based on cross-sectional or/and observational studies highlighting an association of coffee intake and health outcomes; thus, randomized controlled studies are needed in order to identify a causality link.

The Effect of Green Coffee Supplementation on Lipid Profile, Glycemic Indices, Inflammatory Biomarkers and Anthropometric Indices in Iranian Women With Polycystic Ovary Syndrome: A Randomized Clinical Trial

Polycystic ovary syndrome (PCOS) is a heterogeneous clinical syndrome. Recent studies examine different strategies to modulate its related complications. Chlorogenic acid, as a bioactive component of green coffee (GC), is known to have great health benefits. The present study aimed to determine the effect of GC on lipid profile, glycemic indices, and inflammatory biomarkers. Forty-four PCOS patients were enrolled in this randomized clinical trial of whom 34 have completed the study protocol. The intervention group (n = 17) received 400 mg of GC supplements, while the placebo group (n = 17) received the same amount of starch for six weeks. Then, glycemic indices, lipid profiles, and inflammatory parameters were measured. After the intervention period, no significant difference was shown in fasting blood sugar, insulin level, Homeostasis model assessment of insulin resistance index, low-density lipoprotein, high-density lipoprotein, Interleukin 6 or 10 between supplementation and placebo groups. However, cholesterol and triglyceride serum levels decreased significantly in the intervention group (p < 0.05). This research confirmed that GC supplements might improve some lipid profiles in women with PCOS. However, more detailed studies with larger sample sizes are required to prove the effectiveness of this supplement.

Sustained Consumption of a Decaffeinated Green Coffee Nutraceutical Has Limited Effects on Phenolic Metabolism and Bioavailability in Overweight/Obese Subjects

Knowledge on the bioavailability of coffee (poly)phenols mostly come from single dose postprandial studies. This study aimed at investigating the effects of regularly consuming a green coffee phenolic extract (GCPE) on the bioavailability and metabolism of (poly)phenols. Volunteers with overweight/obesity consumed a decaffeinated GCPE nutraceutical containing 300 mg hydroxycinnamates twice daily for two months. Plasma and urinary pharmacokinetics, and fecal excretion of phenolic metabolites were characterized by LC-MS-QToF at weeks 0 and 8. Fifty-four metabolites were identified in biological fluids. Regular consumption of the nutraceutical produced certain changes: reduced forms of caffeic, ferulic and coumaric acids in urine or 3-(3′-hydroxypenyl)propanoic, and 3,4-dihydroxybenzoic acids in feces significantly increased (p < 0.05) after 8 weeks; in contrast, coumaroylquinic and dihydrocoumaroylquinic acids in urine decreased (p < 0.05) compared to baseline excretion. The sum of intestinal and colonic metabolites increased after sustained consumption of GCPE, without reaching statistical significance, suggesting a small overall effect on (poly)phenols’ bioavailability.

Insulin-Related Liver Pathways and the Therapeutic Effects of Aerobic Training, Green Coffee, and Chlorogenic Acid Supplementation in Prediabetic Mice

Background

The liver controls blood glucose levels via regulation of anabolic (glycogen synthesis and gluconeogenesis) and catabolic (glycolysis and glycogenolysis) processes through activation of the PI3K-AKT signalling pathway. The aim of this study was to assess the effect of aerobic training, green coffee, and chlorogenic acid supplementation on glucose metabolism-regulating pathways in prediabetic mice.

Methods

C57BL/6 mice were exposed to a high-fat diet and physical activity limitation to induce a state of prediabetes. After 12 weeks, mice were fed a high-fat diet compared to the control mice. The prediabetic mice were further treated with either green coffee, chlorogenic acid, or training or combinations of the same for 10 weeks. At the end of the experimental period, metabolic data (FBG, GTT, HOMA for IR, plasma level of insulinfrom systematic, AST, and ALT assessed into blood), histopathologic, and analysis of gene and protein expressions were obtained for target tissues.

Results

Training along with green coffee and chlorogenic acid supplementation improved complications of prediabetes including weight gain and elevated fasting blood glucose and plasma insulin levels. These effects were associated with the changes in mRNA levels of genes important in hepatic glycogen synthesis (GYS2), glucogenesis (PCK and G6PC2), and glycolysis (GK, PK, and PFKL).

Conclusion

The training in conjunction with green coffee or chlorogenic acid is effective in the prevention of prediabetes in mice. As these interventions are relatively inexpensive and safe application to individuals with prediabetes appears warranted.

Influence of 8-week daily consumption of a new product combining green coffee hydroxycinnamates and beta-glucans on polyphenol bioavailability in subjects with overweight and obesity

Nutraceuticals based on plant extracts rich in polyphenols, as well as dietary fibres, are new means to fight overweight/obesity and associated diseases. However, to understand the potential effects of polyphenols on health it is critical to study their bioavailability and metabolic fate. Consumption of a green coffee phenolic extract (GCPE) in combination with oat beta-glucan (BG) could affect the pharmacokinetic profile of the main polyphenols present in coffee (hydroxycinnamates). Moreover, the regular intake of the combination could also induce changes. Nine overweight men and women consumed a novel nutraceutical product containing 300 mg of green coffee hydroxycinnamic acids and 2.5 g of BG twice a day for 8 weeks. A pharmacokinetic study was carried out in blood and urine samples taken before (baseline) and at week 8 after the nutraceutical intervention, collecting samples at different times in a 0-24 h interval. Faecal samples were also obtained at 0 and 24 h after the intake of the nutraceutical at baseline and week 8. Phenolic metabolites were analysed by LC-MS-QToF. Results showed that polyphenols were differentially absorbed and extensively metabolized throughout the gastrointestinal tract. An apparent reduction in the excretion of small intestinal metabolites was accompanied by a tendency to increase colonic metabolites after sustained intake (p = 0.052). In conclusion, continued consumption of the GCPE/BG nutraceutical appears to enhance the absorption of hydroxycinnamates by increasing the colonic bioavailability of their derived metabolites compared to baseline, although the regular intake of the nutraceutical did not modify the metabolite profile in any of the biological samples.

Does tibolone treatment have favorable effects on obesity, blood pressure, and inflammation? A meta-analysis of randomized controlled trials

The clinical effects of tibolone on cardiometabolic markers are an underlying question in postmenopausal women. We aimed to meta-analyze the effects of tibolone on anthropometric indicators of obesity, blood pressure (BP), and on C-reactive protein (CRP) levels in postmenopausal women. Two independent reviewers searched Scopus, Web of Science, PubMed/Medline, and Embase up to until 20 April 2021. Weighted mean differences (WMDs) and 95% confidence interval (CI) were calculated through the DerSimonian and Laird random-effect models between the tibolone and the control groups. Data from 20 eligible included showed that tibolone treatment increased the body mass index (BMI) by 0.23 kg/m² (95% CI: 0.017 to 0.45, p = 0.03) but did not significantly increase body weight (WMD: 1.128 kg, 95% CI: -1.76 to 4.02, p = 0.44) or waist circumference (WC) (WMD: 0.64 cm, 95% CI: -3.18 to 4.48, p = 0.74). Also, tibolone treatment neither changed the systolic BP (WMD: 2.60 mmHg, 95% CI: -2.52 to 7.72, p = 0.31) nor the diastolic BP (WMD: 0.711 mmHg, 95% CI: -2.52 to 3.94, p = 0.66), but increased CRP levels by 0.44 mg/L (95% CI: 0.10 to 0.78, p = 0.01). Tibolone treatment administered in postmenopausal women increased BMI and CRP but did not change body weight, WC, and SBP. Diastolic BP decreased after the tibolone intervention only in the studies lasting 26 weeks versus ˃26 weeks.

Evaluation of novel nutraceuticals based on the combination of oat beta-glucans and a green coffee phenolic extract to combat obesity and its comorbidities. A randomized, dose-response, parallel trial

Obesity and its associated comorbidities are a major public health concern worldwide. Reduced energy intake and increased physical activity interventions have limited success in the long term. Nutraceuticals might be an alternative means to help lose weight and reduce obesity-associated cardiometabolic risk factors without changes in the habitual diet. The objective of the present study was to comparatively evaluate the efficiency of nutraceuticals based on the combination of a decaffeinated green coffee bean extract (GCBE) and two types of oat beta-glucans (BG) with different physiochemical properties on obesity related biomarkers in overweight/obese subjects. A randomized, dose-response, parallel, blind study was carried out in four groups of subjects (n = 15 each) who consumed for 6 weeks, twice a day, a nutraceutical containing 3 g d^-1 or 5 g d^-1 doses of 35% or 70% BG and a fixed amount of GCBE providing 600 mg d^-1 of phenols. 35% BG showed a 10 and 100 times higher molecular weight and viscosity, respectively, compared to 70% BG. Food intake, anthropometry and different cardiometabolic markers were assessed at the beginning and end of the intervention. According to the general model of variance with repeated measure analysis, the intervention caused positive changes in the levels of total cholesterol, LDL cholesterol, VLDL cholesterol, triglycerides, alanine aminotransferase, aspartate aminotransferase, haemoglobin A1c, insulin, systolic blood pressure (SBP), total body fat percentage (TBF%), visceral fat percentage, and waist and hip circumferences without differences among the treatments, except for SBP and TBF%. Looking into the rates of change [(end value - beginning value)/beginning value] of these parameters, 5 g - 70% BG was the treatment that lowered TBF% the most. In conclusion, 5 g - 70% BG may be more effective in helping to lose weight and additionally, it produced the least bloating according to participants' subjective perception.

Vaccinium bracteatum Thunb. fruit extract reduces high-fat diet-induced obesity with modulation of the gut microbiota in obese mice

Vaccinium bracteatum Thunb. fruits have been used as traditional food. This study investigated the effects of a polyphenol-rich Vaccinium bracteatum Thunb. fruit extract (VBTE) on obesity and obesity-related diseases in mice, and the potential role of the gut microbiota in the bioactivity of VBTE was also determined. Chemical constituents of the VBTE were analyzed by liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS/MS). C57BL/6J mice (weighing 17.8-21.6 g) were fed a low-fat diet (LFD) or high-fat diet (HFD) with or without VBTE treatment for 14 weeks. The gut microbial changes were determined using 16S rRNA sequencing. Our results showed that VBTE mainly contains 36 kinds of polyphenols. VBTE reduced HFD-induced body weight gain by 33.42% (p < .05), steatosis scores by 56.25% (p < .05), and insulin resistance index by 51.49% (p < .05). Moreover, VBTE altered the composition of the gut microbiota. The correlation analysis indicated that Akkermansia, Alistipes, Bacteroides, Alloprevotella, Ruminiclostridium, Ruminiclostridium_9, and Rikenellaceae_RC9_gut_group were negatively correlated with serum lipids, glucose, and insulin, while Escherichia-Shigella was positively associated with these clinical indicators. In conclusion, VBTE supplement could reduce obesity and be a treatment option for obesity-related diseases by influencing the gut microbiota in mice. PRACTICAL APPLICATIONS: Plant extracts are widely used to treat obesity and related metabolic disorders. Polyphenols, the well-known natural antioxidants present in fruits, are consumed as a dietary supplement to prevent many diseases. Recent pharmacological studies have reported that Vaccinium bracteatum Thunb. fruits have many physiological functions, such as anti-proliferative, anti-inflammatory, and antidepressant-like effects. Despite these properties of Vaccinium bracteatum Thunb. fruits, their anti-obesity effect has not been studied to date. The findings of this study will support VBTE could be used as an important therapeutic application for preventing obesity and related metabolic diseases by modulating the gut microbiota.

Diet-Derived Antioxidants and Their Role in Inflammation, Obesity and Gut Microbiota Modulation

It is generally accepted that gut microbiota, inflammation and obesity are linked to the development of cardiovascular diseases and other chronic/non-communicable pathological conditions, including cancer, neurodegenerative diseases and ageing-related disorders. In this scenario, oxidative stress plays a pivotal role. Evidence suggests that the global dietary patterns may represent a tool in counteracting oxidative stress, thus preventing the onset of diseases related to oxidative stress. More specifically, dietary patterns based on the regular consumption of fruits and vegetables (i.e., Mediterranean diet) have been licensed by various national nutritional guidelines in many countries for their health-promoting effects. Such patterns, indeed, result in being rich in specific components, such as fiber, minerals, vitamins and antioxidants, whose beneficial effects on human health have been widely reported. This suggests a potential nutraceutical power of specific dietary components. In this manuscript, we summarize the most relevant evidence reporting the impact of dietary antioxidants on gut microbiota composition, inflammation and obesity, and we underline that antioxidants are implicated in a complex interplay between gut microbiota, inflammation and obesity, thus suggesting their possible role in the development and modulation of chronic diseases related to oxidative stress and in the maintenance of wellness. Do all roads lead to Rome?

Supplementation of green coffee bean extract in healthy overweight subjects increases lean mass/fat mass ratio: A randomized, double-blind clinical study

Objective

In this study, we have demonstrated that supplementation of a complex of chlorogenic acid isomers (CGA-7^TM) could significantly mitigate the risk of obesity in healthy overweight subjects.

Method

In a double-blind, placebo-controlled clinical study, healthy overweight (body mass index ⩾ 25 to <30 kg/m²) male and female subjects (N = 71) were randomly allocated to receive 500 mg CGA-7 or placebo daily for 12 weeks. Changes in body weight and body mass index were recorded alongside vital signs and anthropometric measurements at week 4, 8 and 12. Body composition was assessed at baseline and the end of treatment using dual-energy X-ray absorptiometry. Safety analysis included serum biochemical and haematological assessments and measurement of vital signs. In addition, any adverse or serious adverse events were recorded during the study.

Results

Sixty subjects completed the study. Mean body weight and body mass index were significantly reduced in CGA-7 group as compared to placebo (p < 0.001). CGA-7 group showed significant changes in body fat (%), fat mass and lean mass in comparison with placebo group (1.38% ± 1.4% vs -0.22% ± 0.86%, 1.97 ± 1.44 kg vs -0.39 ± 1.31 kg; 0.81 ± 1.20 kg vs -0.13 ± 0.97 kg, p < 0.001). Consumption of CGA-7 significantly improved the serum lipid profile. Importantly, CGA-7 consumption in humans had no adverse effects and was well tolerated during the study. The blood biochemical and haematological parameters marginally varied in the treatment groups throughout the study.

Conclusion

To conclude, this study provides scientific validation of the functionality of green coffee bean extract and recommends the safety of the supplementation in healthy individuals.

Polyphenols in foods: Classification, methods of identification, and nutritional aspects in human health

Polyphenols widely exists in various foods, including main crops, fruits, beverages and some wines. Famous representatives of polyphenols, such as resveratrol in red wine, (-)-epigallocatechin gallate in green tea, chlorogenic acid in coffee, anthocyanins in colored fruits, procyanidins in grape seed have become hot research topics in food science and nutrition. There have been thousands of papers on the biochemistry, chemistry, nutritional values and population-based investigations of dietary polyphenols. In this chapter, we reviewed the published articles and database of dietary polyphenols to draw a profile for the classification, structural identification, and biological activities mainly based on enzymes, cell bioassay and animal models, as well as the population-based investigation results. The typical compound and its health benefits for each category of polyphenols was also introduced. The identification of dietary polyphenols could be solved by combined spectroscopy methods, of which the liquid chromatography tandem mass spectrometry is highlighted to greatly increase the efficiency on structural identification. Although the population-based investigation showed some controversial results for health benefits, the multi-functions of dietary polyphenols on preventing metabolic syndromes, various cancers and neurodegenerative disease have attracted much attention.

The effect of paleolithic diet on glucose metabolism and lipid profile among patients with metabolic disorders: a systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

Several randomized clinical trials (RCTs) have investigated the effects of the Paleolithic diet (PD) in adult patients suffering from metabolic disorders. However, the results of these RCTs are conflicting. Therefore, we conducted a systematic review and meta-analysis to assess the effects of the PD in patients with metabolic disorders.

METHODS

We searched the PubMed/Medline, Scopus, Cochrane Databases, Google Scholar, Web of Science, and Embase databases up to June, 2020. The data were pooled using a random-effects model. From the eligible publications, 10 articles were selected for inclusion in this systematic review and meta-analysis. The meta-analysis was performed using a random-effects model. The heterogeneity was determined using the I² statistics and the Cochrane Q test.

RESULTS

The pooled results from the random-effects model showed a significant reduction of the homeostatic model assessment of insulin resistance (HOMA-IR) (weighted mean difference, WMD: -0.39, 95% CI: -0.70, -0.08), fasting insulin (WMD: -12.17 μU/mL, 95% CI: -24.26, -0.08), total cholesterol (WMD: -0.32 mmol/l, 95% CI: -0.49, -0.15), triglycerides (WMD: -0.29 mmol/L, 95% CI: -0.42, -0.16), low-density lipoprotein cholesterol (WMD: -0.35 mmol/L, 95% CI: -0.67, -0.03), blood pressure (BP)(WMD - 5.89 mmHg; 95% CI - 9.973 to - 1.86 for the systolic BP and WMD - 4.01 mmHg; 95% CI - 6.21 to - 1.80 for the diastolic BP values) and C-reactive protein (CRP) levels (WMD: -0.84, mg/L, 95% CI: -1.62, -0.06) in the PD group versus control group.

CONCLUSIONS

Our findings provide better insights into the effect of the PD on the modulation of the glucose and lipid metabolism factors in patients with metabolic disorders, providing comprehensive information for the development of future RCTs with a high quality design.

The effect of Bertholletia excelsa on body weight, cholestrol, and c-reactive protein: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND & OBJECTIVE(S)

Bertholletia excelsa is a rich herbal source of anti-oxidants and phenols. The goal of this study is to evaluation the effect of bertholletia excelsa nut on body weight, C-reactive protein (CRP) and lipid profile.

METHODS

A literature search was conducted in PubMed, Scopus and Web of sciences databases by two reviewers up to October 2019. Random effect model used to combine results.

RESULTS

Six studies included in analysis with 71 participants. The population was public population. Pooled results showed Bertholletia excelsa have reduction effect on triglyceride weighted mean difference (WMD: -8.23 mg/dl, 95 % CI -15.09, -1.38, I² = 0%), Cholesterol (WMD: -14.31 mg/dl, 95 % CI -23.38, -5.24, I² = 47 %), Low-density lipoprotein (LDL) (WMD: -9.27 mg/dl, 95 % CI -13.48, -5.06, I² = 0%).

CONCLUSION

This study provided an evidence that Bertholletia excelsa nuts have reduction effect on triglyceride, cholesterol, and LDL levels.

The effects of lycopene supplementation on serum insulin-like growth factor 1 (IGF-1) levels and cardiovascular disease: A dose-response meta-analysis of clinical trials

BACKGROUND

The results of human studies assessing the efficacy of lycopene on insulin-like growth factor 1 (IGF-1) levels are inconsistent. Thus, we performed a systematic review and meta-analysis to examine the effects of lycopene supplementation on serum IGF-1 levels and cardiovascular disease.

METHODS

The literature published up to January 2020 was searched using the electronic databases Scopus, PubMed/Medline, Web of Science, Embase and Google Scholar.

RESULTS

Seven qualified trials were included in the current meta-analysis. IGF-1 levels were non-significantly decreased in lycopene group compared to the control (WMD: -6.74 ng/mL, 95 % CI: -23.01 to 9.52, p = 0.42; I² = 94.3 %). Subgroup analysis revealed a significantly decrease in IGF-1 levels upon lycopene supplementation at doses ≥15 mg/d (WMD: -6.40 ng/mL), intervention period <12 weeks (WMD: -6.49 ng/mL), and subjects aged ≥60 years (WMD: -24.98 mg/dl). In addition, lycopene intake significantly reduced IGF-1 levels upon healthy conditions (WMD: -25.59 ng/mL) when compared with cancer patients (WMD: 0.35 ng/mL). In addition, the effect of lycopene supplementation was significant in patients diagnosed with cardiac disorders.

CONCLUSION

Overall, lycopene intake was not associated with reduced serum IGF-1 levels. However, association was significant when lycopene was administrated at doses >15 mg/d, for <12 weeks, as well as for healthy conditions and patients aged ≥60 years. In addition, lycopene supplementation exhibited potential health benefits in the management of patients with cardiac disorders.

Effects of green coffee bean extract on C-reactive protein levels: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND & OBJECTIVE

The effects of green coffee bean extract (GCBE) supplementation on inflammatory biomarkers have been widely spread. The purpose of this article was to assess the impact of GCBE supplementation on C-reactive protein (CRP) levels.

METHODS

The literature search was performed in four databases (Scopus, PubMed, the Cochrane Library, and Google Scholar) to identify studies that examined the influence of GCBE supplementation on CRP levels up to August 2019. Mean and standard deviation (SD) of the outcomes were used to estimate the weight mean difference (WMD) between intervention and control groups for the follow-up period.

RESULTS

Five (5) studies, with 6 arms, reported CRP as an outcome. Statistically, the use of GCBE supplements resulted in a significant change in CRP levels (WMD: -0.017 mg/dL, 95 % CI: -0.032, -0.003, p = 0.018), whose overall findings were obtained from random-effects model. In addition, a significantly greater reduction in CRP was noted for studies with doses of GCBE supplements ≥ 1000 mg/d (WMD: -0.015 mg/dL, 95 % CI: -0.020, -0.010, p < 0.000), length of intervention < 4 weeks (WMD: -0.015 mg/dL, 95 % CI: -0.020, -0.010, p < 0.001), and for non-healthy subjects (WMD: -0.019 mg/dL, 95 % CI: -0.027, -0.011, p < 0.001). Dyslipidemia, hypertension and non-alcoholic fatty liver disease were the ailments of the studies that encompassed non-healthy patients.

CONCLUSIONS

This meta-analysis shows that the use of GCBE supplements resulted in a statistical decrease in CRP levels, mainly for non-healthy subjects. However, due to the limited number of studies, further randomized clinical trials are crucial in this regard.

The effect of green coffee extract supplementation on anthropometric measures in adults: A comprehensive systematic review and dose-response meta-analysis of randomized clinical trials

BACKGROUND AND AIM

Two meta-analyses summarized data on the effects of green coffee extract (GCE) supplementation on anthropometric measures. However, the accuracy of those meta-analyses is uncertain due to several methodological limitations. Therefore, we aimed to conduct a comprehensive systematic review and dose-response meta-analysis to summarize all available evidence on the effects of GCE supplementation on anthropometric measures by considering the main limitations in the previous meta-analyses.

METHODS

We searched available online databases for relevant publications up to January 2020, using relevant keywords. All randomized clinical trials (RCTs) investigating the effects of GCE supplementation, compared with a control group, on anthropometric measures [including body weight, body mass index (BMI), body fat percentage, waist circumference (WC) and waist-to-hip ratio (WHR)] were included.

RESULTS

After identifying 1871 studies from our initial search, 15 RCTs with a total sample size of 897 participants were included in the systematic review and meta-analysis. We found a significant reducing effect of GCE supplementation on body weight (weighted mean difference (WMD): -1.23, 95 % CI: -1.64, -0.82 kg,P < 0.001), BMI (WMD: -0.48, 95 % CI: -0.78, -0.18 kg/m², P = 0.001), and WC (WMD: -1.00, 95 % CI: -1.70, -0.29 cm, P = 0.006). No significant effect of GCE supplementation on body fat percentage and WHR was seen. In the dose-response analyses, there was no significant association between chlorogenic acid (CGA) dosage, as the main polyphenol in green coffee, and changes in anthropometric measures.

CONCLUSION

We found that GCE supplementation had a beneficial effect on body weight, BMI and WC. It provides a cost-effective and safe alternative for the treatment of obesity. Additional well-designed studies are required to further confirm our findings.

A Critical Review on the Role of Food and Nutrition in the Energy Balance

The mass media has increasingly frequently suggested to the general population that specific foods or nutritional schemes are able to affect both human metabolism and energy expenditure, thus facilitating weight loss. This critical review is aimed at assessing available evidence on the roles of nutrients, food and dietary regimens in energy intake and energy expenditure. We queried the National Library of Medicine, the Cochrane Library, Excerpta Medica dataBASEand the Cumulative Index to Nursing and Allied Health Literature database, and a search strategy was performed by using database-specific subject headings and keywords. We found that available scientific evidence on these topics is scarce, and that the limited number of available studies often have poor methodological quality. Only a few foods show beneficial effects on metabolism and energy expenditure, as the human energy balance is complex and multifactorial. Finally, microbiota may interfere with the intake, use and expenditure of energy in the human body. Conclusive evidence is still lacking, and, at present, it is not possible to identify a food or a diet with a significant impact on human energy expenditure.

The influence of green coffee bean extract supplementation on blood glucose levels: A systematic review and dose-response meta-analysis of randomized controlled trials

Studies regarding the influence of green coffee extract (GCE) on blood glucose levels are conflicting. Thus, we sought to conduct a meta-analysis and systematic review of all available randomized controlled trials (RCTs) to quantify the effects of GCE and CGA intervention on blood glucose and insulin levels. We performed systematic online searches in Scopus, Web of science, and PubMed databases, from inception to July 2019. Data were combined analyzed using a random effects model (Der Simonian-Laird method) and reported as weighted mean differences (WMD). Ten trials reported the influences of GCE on FBS and insulin and were subsequently entered into the meta-analysis. Combined results highlighted that FBS was significantly altered after GCE consumption (WMD: -1.791 mg/dl, 95% CI -3.404, -0.177), with no significant heterogeneity among the studies (I² = 35.0%, p = .128). However, overall results demonstrated that GCE administration did not result in any significant alteration in insulin levels (WMD: -0.925 μU/ml, 95% CI:-1.915, 0.064), with significant heterogeneity found across studies (I² = 87.9%). In sub-group analysis, insulin levels were significantly reduced when GCE was supplemented in dosages of ≥400 mg/day (WMD:-1.942 mg/dl, 95% CI:-1.184, -0.975; I² = 0.0%). The results of present study support the use of GCE for the enhancement of blood glucose, while subgroup analysis highlighted significant improvements in insulin levels when GCE is supplemented in doses ≥400 mg/day.

The effects of green coffee bean extract supplementation on lipid profile in humans: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND AND AIM

This systematic review and meta-analysis aimed to assess the effects of green coffee bean extract (GCBE) supplementation on lipid profile in adults.

METHODS AND RESULTS

The PubMed/Medline, Scopus, Web of sciences, and Google Scholar were systematically searched for randomized controlled trials available in English and published before February 2019. The meta-analysis was conducted using fixed effects models, and between-study heterogeneity was assessed by Cochran's Q test and I². A total of 17 effect sizes were included in the meta-analysis. Combined effect sizes on serum total cholesterol concentrations revealed significant effects of GCBE supplementation on serum total cholesterol [weighted mean difference (WMD): -4.51 mg/dL, 95% confidence interval (CI): -6.89, -2.12, p < 0.001], low density lipoprotein-cholesterol (LDL-C) (WMD: -4.38 mg/dL, 95% CI: -6.44, -2.31, p < 0.001), and high density lipoprotein-cholesterol (HDL-C) (WMD: 2.63 mg/dL, 95% CI: 2.20, 3.07, p < 0.001) compared to controls. Nevertheless, no significant changes were observed in serum triglycerides levels (WMD: -4.34 mg/dL, 95% CI: -9.00, 0.32, p = 0.068).

CONCLUSION

The evidence from available studies suggests that the GCBE supplementation leads to significant reductions in total cholesterol, HDL-C, and LDL-C levels, and has modest, but, non-significant effects on triglycerides levels.