Coffee consumption and risk of type 2 diabetes, cardiovascular diseases, and cancer

A Narrative Review on Strategies for the Reversion of Prediabetes to Normoglycemia: Food Pyramid, Physical Activity, and Self-Monitoring Innovative Glucose Devices

In 2019, "Nutrition Therapy for Adults with Diabetes or Prediabetes: A Consensus Report" was published. This consensus report, however, did not provide an easy way to illustrate to subjects with prediabetes (SwPs) how to follow a correct dietary approach. The purpose of this review is to evaluate current evidence on optimum dietary treatment of SwPs and to provide a food pyramid for this population. The pyramid built shows that everyday consumption should consist of: whole-grain bread or potatoes eaten with their skins (for fiber and magnesium) and low glycemic index carbohydrates (GI < 55%) (three portions); fruit and vegetables (5 portions), in particular, green leafy vegetables (for fiber, magnesium, and polyphenols); EVO oil (almost 8 g); nuts (30 g, in particular, pistachios and almonds); three portions of dairy products (milk/yogurt: 300-400 g/day); mineral water (almost 1, 5 L/day for calcium intake); one glass of wine (125 mL); and three cups of coffee. Weekly portions should include fish (four portions), white meat (two portions), protein plant-based food (four portions), eggs (egg portions), and red/processed meats (once/week). At the top of the pyramid, there are two pennants: a green one means that SwPs need some personalized supplementation (if daily requirements cannot be satisfied through diet, vitamin D, omega-3, and vitamin B supplements), and a red one means there are some foods and factors that are banned (simple sugar, refined carbohydrates, and a sedentary lifestyle). Three to four times a week of aerobic and resistance exercises must be performed for 30-40 min. Finally, self-monitoring innovative salivary glucose devices could contribute to the reversion of prediabetes to normoglycemia.

Chlorogenic acid improves anti-lipogenic activity of metformin by positive regulating of AMPK signaling in HepG2 cells

Metformin improves lipid profile, however, combination therapy is developing to increase its effectiveness and reduce the deleterious effects of metformin. Chlorogenic acid (CGA) has exhibited lipid-lowering effects. This study aimed to investigate the combined effect of metformin and CGA on lipid accumulation, as well as to elucidate the engaged mechanism in HepG2 cells. To find the non-lethal doses of metformin and CGA, MTT assay was performed. High Glucose (HG) at 33 mM was used to induce lipogenesis in HepG2 cells. Following treatment with different concentrations of metformin and CGA, total lipid content (Oil Red O-staining), triglyceride level, the genes expression of SREBP-1c and FAS, and phosphorylation of AMPK and ACC were measured. Both Metformin and CGA decreased HG-induced lipid accumulation individually, by decreasing total lipid content and triglyceride level. The lowest effective doses of metformin and CGA were 0.25 mM and 5 μM, respectively, which significantly reduced SREBP-1c and FAS genes expression. The combination of these concentrations reinforced these effects. The phosphorylation of AMPK and ACC were more increased by metformin in combination with CGA than both individually. Our findings suggest that CGA synergistically enhances metformin lipid reducing action via the regulating of involved factors in fatty acid synthesis. Therefore, co-administration of metformin with CGA may have further medical value in treating lipid metabolism disorders.

Coffee Chlorogenic Acids Incorporation for Bioactivity Enhancement of Foods: A Review

The demand of foods with high antioxidant capacity have increased and research on these foods continues to grow. This review is focused on chlorogenic acids (CGAs) from green coffee, which is the most abundant source. The main CGA in coffee is 5-O-caffeoylquinic acid (5-CQA). Coffee extracts are currently the most widely used source to enhance the antioxidant activity of foods. Due to the solubility of CGAs, their extraction is mainly performed with organic solvents. CGAs have been associated with health benefits, such as antioxidant, antiviral, antibacterial, anticancer, and anti-inflammatory activity, and others that reduce the risk of cardiovascular diseases, type 2 diabetes, and Alzheimer's disease. However, the biological activities depend on the stability of CGAs, which are sensitive to pH, temperature, and light. The anti-inflammatory activity of 5-CQA is attributed to reducing the proinflammatory activity of cytokines. 5-CQA can negatively affect colon microbiota. An increase in anthocyanins and antioxidant activity was observed when CGAs extracts were added to different food matrices such as dairy products, coffee drinks, chocolate, and bakery products. The fortification of foods with coffee CGAs has the potential to improve the functionality of foods.

Light to moderate coffee consumption is associated with lower risk of death: a UK Biobank study

AIMS

To study the association of daily coffee consumption with all-cause and cardiovascular (CV) mortality and major CV outcomes. In a subgroup of participants who underwent cardiovascular magnetic resonance (CMR) imaging, we evaluated the association between regular coffee intake and cardiac structure and function.

METHODS AND RESULTS

UK Biobank participants without clinically manifested heart disease at the time of recruitment were included. Regular coffee intake was categorized into three groups: zero, light-to-moderate (0.5-3 cups/day), and high (>3 cups/day). In the multivariate analysis, we adjusted for the main CV risk factors. We included 468 629 individuals (56.2 ± 8.1 years, 44.2% male), of whom 22.1% did not consume coffee regularly, 58.4% had 0.5-3 cups per day, and 19.5% had >3 cups per day. Compared to non-coffee drinkers, light-to-moderate (0.5-3 cups per day) coffee drinking was associated with lower risk of all-cause mortality [multivariate hazard ratio (HR) = 0.88, 95% confidence interval (CI): 0.83-0.92; P < 0.001] and CV mortality (multivariate HR = 0.83, 95% CI: 0.74-0.94; P = 0.006), and incident stroke (multivariate HR = 0.79, 95% CI: 0.63-0.99 P = 0.037) after a median follow-up of 11 years. CMR data were available in 30 650 participants. Both light-to-moderate and high coffee consuming categories were associated with dose-dependent increased left and right ventricular end-diastolic, end-systolic and stroke volumes, and greater left ventricular mass.

CONCLUSION

Coffee consumption of up to three cups per day was associated with favourable CV outcomes. Regular coffee consumption was also associated with a likely healthy pattern of CMR metrics in keeping with the reverse of age-related cardiac alterations.

Coffee Consumption May Mitigate the Risk for Acute Kidney Injury: Results from the Atherosclerosis Risk in Communities (ARIC) Study

Introduction

Coffee is one of the most frequently consumed beverages worldwide and has been found to have a wide assortment of health benefits. Although habitual coffee consumption is associated with a lower incidence of chronic kidney disease, an association between coffee and acute kidney injury (AKI) has not yet been revealed.

Methods

In the Atherosclerosis Risk in Communities (ARIC) Study, a prospective cohort study of 14,207 adults aged 45 to 64 years, coffee consumption (cups/d) was assessed at a single visit via food frequency questionnaires and compared with incident AKI defined by hospitalization with an AKI-related International Classification of Diseases code.

Results

In ARIC, there were 1694 cases of incident AKI in a median of 24 follow-up years. Higher coffee consumption was associated with lower AKI risk versus no consumption (hazard ratio [HR] <1 cup/d: 0.92 [95% CI: 0.79–1.08]; 1 cup/d: 1.08 [95% CI: 0.94–1.24]; 2 to 3 cups/d: 0.83 [95% CI: 0.72–0.95]; >3 cups/d: 0.83 [95% CI: 0.71–0.96]; reference: never, P = 0.003). Trends for AKI risk across coffee categories remained significant after multivariable adjustment for age, sex, race-center, education, total daily energy intake, physical activity, smoking, alcohol intake, diet quality (Dietary Approaches to Stop Hypertension [DASH] score), systolic blood pressure (BP), diabetes status, use of antihypertensive agents, estimated glomerular filtration rate (eGFR), and body mass index (BMI) (P = 0.02).

Conclusion

Higher coffee intake was associated with a lower risk of incident AKI and could present an opportunity for cardiorenal protection through diet. Further evaluation of the physiological mechanisms underlying the cardiorenal protective effects of coffee consumption is necessary.

The role of sugar-sweetened beverages in the global epidemics of obesity and chronic diseases

Sugar-sweetened beverages (SSBs) are a major source of added sugars in the diet. A robust body of evidence has linked habitual intake of SSBs with weight gain and a higher risk (compared with infrequent SSB consumption) of type 2 diabetes mellitus, cardiovascular diseases and some cancers, which makes these beverages a clear target for policy and regulatory actions. This Review provides an update on the evidence linking SSBs to obesity, cardiometabolic outcomes and related cancers, as well as methods to grade the strength of nutritional research. We discuss potential biological mechanisms by which constituent sugars can contribute to these outcomes. We also consider global trends in intake, alternative beverages (including artificially-sweetened beverages) and policy strategies targeting SSBs that have been implemented in different settings. Strong evidence from cohort studies on clinical outcomes and clinical trials assessing cardiometabolic risk factors supports an aetiological role of SSBs in relation to weight gain and cardiometabolic diseases. Many populations show high levels of SSB consumption and in low-income and middle-income countries, increased consumption patterns are associated with urbanization and economic growth. As such, more intensified policy efforts are needed to reduce intake of SSBs and the global burden of obesity and chronic diseases.

The Effect of Green Coffee Bean Extract on Cardiovascular Risk Factors: A Systematic Review and Meta-analysis

BACKGROUND AND AIM

Cardiovascular disease remains the primary cause of noncommunicable disease- related death. The present systematic review and meta-analysis was performed to assess the possible benefit of the green coffee bean extract on cardio-metabolic markers.

METHODS

PubMed, Scopus, Web of Science, and Cochrane Library were systematically searched to identify clinical trials that examined the effect of green coffee bean extract on cardio-metabolic risk factors including serum lipid profiles, glycemic status-related markers, blood pressure, and anthropometric indices. Since the included RCTs were carried out in different settings, random effect models were used to conduct all meta-analyses.

RESULTS

Fifteen studies (19 arms) consisting of 637 participants were included. The results indicated that green coffee bean extract significantly reduced levels of total cholesterol (-5.93 mg/dl; 95% CI: -9.21, -2.65; I²: 0%), fasting plasma glucose (-2.21 mg/dl; 95% CI: -3.94, -0.48; I²: 32%), systolic blood pressure (-3.08 mmHg; 95% CI: -4.41, -1.75; I²: 26%), diastolic blood pressure (-2.27 mmHg; 95% CI: -3.82, -0.72; I²: 61%), body weight (-1.24 kg; 95% CI: -1.82, -0.66; I²: 15%), and BMI (-0.55 kg/m²; 95% CI: -0.88, -0.22; I²: 73%). Although the pooled effect size of LDL-C, fasting insulin, and waist circumstance were significant, the results were significantly influenced by individual studies. No significant effect was detected for triglycerides, HDL-C, HbA1C, and HOMA-IR. However, the nonsignificant pooled effect size for triglyceride levels was influenced by one individual study.

CONCLUSION

The present study suggests that green coffee been extract consumption can improve total cholesterol, triglycerides, body weight, blood pressure, and fasting plasma glucose.

Caffeine as a Factor Influencing the Functioning of the Human Body-Friend or Foe?

Nowadays, caffeine is one of the most commonly consumed substances, which presents in many plants and products. It has both positive and negative effects on the human body, and its activity concerns a variety of systems including the central nervous system, immune system, digestive system, respiratory system, urinary tract, etc. These effects are dependent on quantity, the type of product in which caffeine is contained, and also on the individual differences among people (sex, age, diet etc.). The main aim of this review was to collect, present, and analyze the available information including the latest discoveries on the impact of caffeine on human health and the functioning of human body systems, taking into account the role of caffeine in individual disease entities. We present both the positive and negative sides of caffeine consumption and the healing properties of this purine alkaloid in diseases such as asthma, Parkinson's disease, and others, not forgetting about the negative effects of excess caffeine (e.g., in people with hypertension, children, adolescents, and the elderly). In summary, we can conclude, however, that caffeine has a multi-directional influence on various organs of the human body, and because of its anti-oxidative properties, it was, and still is, an interesting topic for research studies including those aimed at developing new therapeutic strategies.

Effect of Serum Ferritin on the Association Between Coffee Intake and Hyperuricemia Among American Women: The National Health and Nutrition Examination Survey

Background

Accruing evidence suggests an inverse relationship between coffee intake and serum uric acid. The mechanism(s) explaining this inverse relationship remains elusive. The aim of this study was to assess if the association between coffee intake and hyperuricemia is mediated via serum ferritin in women.

Methods

We pooled data from the 2003 to 2006 National Health and Nutrition Examination Survey (NHANES). We included women with complete information on all key variables. Coffee intake was classified as none, <1 cup/day, 1-3 cups/day, and ≥4 cups/day. Hyperuricemia was defined as serum uric acid >5.7 mg/dL. We assessed the association between coffee intake and hyperuricemia using logistic regression. Path analysis was used to examine whether serum ferritin mediated the effect of coffee on hyperuricemia.

Results

Among 2,139 women (mean age: 31.2 years [SD: 9.2]), mean serum uric acid was 4.4 mg/dL (SD: 1.0), and 227 (10.6%) had hyperuricemia. In multivariate logistic regression models, intake of ≥4 cups/day of coffee was associated with lower odds of hyperuricemia (OR 0.28 [95% CI: 0.09, 091], P=0.035). The total direct and indirect effect of coffee on hyperuricemia via serum ferritin was −0.16, P=0.009 and −8.1 × 10⁻³, P=0.204, respectively.

Conclusion

Among women, moderate coffee consumption was inversely related to hyperuricemia by direct effect, rather than indirectly through the effects of serum ferritin. These findings suggest that serum ferritin does not mediate the inverse association between coffee and hyperuricemia in women.

Effect of green coffee bean extract supplementation on liver function and inflammatory biomarkers: A meta-analysis of randomized clinical trials

Inflammation is considered a major contributor to non-alcoholic fatty liver disease (NAFLD) and several chronic diseases such as, cardiovascular disease and type two diabetes. Green coffee bean extract (GCBE) supplementation has been suggested to enhancing antioxidant capacity in people with obesity but results across studies are mixed. We conducted a meta-analysis of randomized controlled trials of GCBE supplementation in overweight/obese with normal liver function and NAFLD adults with ALT, AST, γ-GTP, ALP, LDH, CRP, IL-6, and TNF-α as outcomes by searching PubMed and other databases. Eight studies were included, totaling 330 participants randomized to GCBE supplementation or placebo ranging from 50 mg/day to 1200 mg/day for 8-12 weeks. GCBE supplementation resulted in lower levels of TNF-α (mean difference = 1.37 pg/mL [95% CI = 0.97-1.76]; p < 0.00001). No significant difference was found in the remaining markers. In conclusion, GCBE supplementation attenuated TNF-α, a circulating inflammatory marker mediator which may be linked with lower systemic inflammation. However, potential cellular and molecular mechanisms by which GCBE exerts this positive effect warrants further investigations in human model studies.

Safety of coffee consumption after myocardial infarction: A systematic review and meta-analysis

BACKGROUND AND AIMS

This systematic review aims to evaluate the impact of coffee consumption in patients with previous myocardial infarction (MI), in relation to all-cause and cardiovascular mortality, as well as other major cardiovascular events (MACE) such as stroke, heart failure, recurrent MI and sudden death.

METHODS AND RESULTS

MEDLINE, Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science Core Collection, SciELO Citation Database, Current Contents Connect®, KCI Korean Journal Database, African Index Medicus, and LILACS were searched for longitudinal studies evaluating the impact of coffee consumption in patients with previous myocardial infarction. We performed a random-effects meta-analysis to estimate the pooled hazard ratios (HR) with 95% confidence intervals (CI). The statistical heterogeneity was measured by I². A dose-response analysis was also conducted. Six prospective cohort studies were included in the primary meta-analysis. Consumption of coffee was associated with lower risk of cardiovascular mortality (HR = 0.70; 95% CI 0.54-0.91, I² = 0%; 2 studies) and was not associated with an increased risk of all-cause mortality (HR = 0.85; 95% CI 0.63-1.13; I² = 50%; 3 studies), recurrent MI (HR = 0.99; 95% CI 0.80-1.22; I² = 0%; 3 studies), stroke (HR = 0.97; 95% CI 0.63-1.49; I² = 39%; 2 studies) and MACE (HR = 0.96; 95% CI 0.86-1.07; I² = 0%; 2 studies). A significant non-linear inverse dose-response association was found for coffee consumption and all-cause mortality.

CONCLUSIONS

Consumption of coffee was not associated with an increased risk of all-cause mortality and cardiovascular events in patients with previous myocardial infarction.

Effect of Coffee Consumption on Renal Outcome: A Systematic Review and Meta-Analysis of Clinical Studies

OBJECTIVE

Drinking coffee is one of the most common daily habits, especially in the developed world. Along with caffeine, coffee has various ingredients that have been suggested to have beneficial effects, including antioxidant, antiinflammatory, anticarcinogenic, antithrombotic and antifibrotic effects. In this systematic review and meta-analysis, we investigated the relationship between coffee intake and chronic kidney disease (CKD) related outcomes.

DESIGN AND METHODS

Literature search was performed through PubMed/Medline, Web of Science, Embase (Elsevier), and the Cochrane Central Register of Controlled Trials (Wiley) from 1960 to February 2020. Incidence of CKD, the progression of CKD, and CKD-associated mortality have been evaluated in relation to coffee consumption and the amount of consumption. The Newcastle-Ottawa scale was used for quality assessment of included studies.

RESULTS

12 studies were included in the analysis (7 prospective, 5 cross-sectional) involving 505,841 subjects. 7 studies investigated the relationship between coffee consumption and incident CKD and showed that coffee consumption was associated with a significant decrease in the risk for incident CKD outcome (RR 0.86, 95% CI 0.76 to 0.97, P = .01) with a greater decrease in individuals taking ≥2 cups/day compared to those who drank ≤1 cup/day. There was a significantly lower risk of incident end stage kidney disease (ESKD) in coffee users (HR 0.82, 95% CI 0.72 to 0.94, P = .005). Coffee consumption was also associated with a lower risk of albuminuria (OR 0.81, 95% CI 0.68 to 0.97, P = .02). Overall, the risk of death related to CKD was lower in coffee users (HR 0.72, 95% CI 0.54 to 0.96, P = .02).

CONCLUSION

Coffee intake was dose-dependently associated with lower incident CKD, ESKD, and albuminuria.

Effect of one time coffee fragrance inhalation on working memory, mood, and salivary cortisol level in healthy young volunteers: a randomized placebo controlled trial

Background

Olfactory system regulates the brain which controls emotional memory. Coffee is one of the most consumed beverages in the world. Drinking coffee shows beneficial effects for mood, memory, and psychomotor performance. This work aimed to determine the effects of inhaling coffee fragrance on memory, mood, and salivary cortisol level in healthy young volunteers.

Methods

Eighty young males and females, aged between 18–22 years old, were randomly assigned into two groups: a placebo group inhaling scent from carbon powder and a coffee fragrance group inhaling coffee fragrance. Subjects were assigned to inhale either placebo or coffee fragrance for five minutes. Before and after inhalation period, the clinical assessments were assigned to each subject including computerized assessment battery test for cognitive performance, and self-related visual analogue mood scales for evaluation of mood score. The salivary cortisol level was assessed with cortisol ELISA kit. In addition, the blood pressure and heart rate were also evaluated.

Results

Inhalation of coffee fragrance enhanced cognitive parameters, including continuity of attention, quality of memory, and speed of memory, and also increased the mood score of alertness. However, there were no significant changes in salivary cortisol level, blood pressure, and heart rate between pre-and post-inhalation.

Conclusion

One time of coffee fragrance inhalation may enhance working memory and stimulates alertness. However, inhaling coffee fragrance does not reduce stress or modulate autonomic response to stress.

A Metabolomic Study of Biomarkers of Habitual Coffee Intake in Four European Countries

SCOPE

The goal of this work is to identify circulating biomarkers of habitual coffee intake using a metabolomic approach, and to investigate their associations with coffee intake in four European countries.

METHODS AND RESULTS

Untargeted mass spectrometry-based metabolic profiling is performed on serum samples from 451 participants of the European Prospective Investigation on Cancer and Nutrition (EPIC) originating from France, Germany, Greece, and Italy. Eleven coffee metabolites are found to be associated with self-reported habitual coffee intake, including eight more strongly correlated (r = 0.25-0.51, p < 10E-07 ). Trigonelline shows the highest correlation, followed by caffeine, two caffeine metabolites (paraxanthine and 5-Acetylamino-6-amino-3-methyluracil), quinic acid, and three compounds derived from coffee roasting (cyclo(prolyl-valyl), cyclo(isoleucyl-prolyl), cyclo(leucyl-prolyl), and pyrocatechol sulfate). Differences in the magnitude of correlations are observed between countries, with trigonelline most highly correlated with coffee intake in France and Germany, quinic acid in Greece, and cyclo(isoleucyl-prolyl) in Italy.

CONCLUSION

Several biomarkers of habitual coffee intake are identified. No unique biomarker is found to be optimal for all tested populations. Instead, optimal biomarkers are shown to depend on the population and on the type of coffee consumed. These biomarkers should help to further explore the role of coffee in disease risk.

The Effect of Fermented Soybean Meal on Performance, Biochemical and Immunological Blood Parameters in Turkeys

The aim of the present study was to assess the effect of different levels of fermented soybean meal on growth performance, intestinal morphology, metabolic indicators, and immunity in turkeys. The material for the study consisted of day-old BIG 6 turkeys raised to the age of 112 days. The experiment was carried out on 800 turkey hens (10 replications of 20 individuals each), assigned to 4 experimental groups of 200 birds each. The feed for the control group (FSBM0) was a standard mix without fermented soybean meal. For turkeys from groups FSBM7, FSBM9 and FSBM10 the diet contained 70, 90 or 100 g fermented soybean meal (FSBM) per kg of feed, respectively. The study showed that including fermented soybean meal in feed for turkeys at 7% improved intestinal histology and stimulated the immune and antioxidant systems. The use of higher level of FSBM (9% and 10%) in the diet of the turkeys improved growth performance and had a beneficial effect on the histology of the small intestine. The dietary inclusion of 10% FSBM had beneficial effect on red-blood-cell parameters, but caused negative impact on liver and kidney function (an increase of aminotransferases activity, content of glucose and creatinine in turkeys’ blood). Ten percent share of FSBM in feed contributed to an adverse intensification of oxidation and inflammatory reactions which were reflected by an increase of malonyldialdehyde, lipid peroxides level and proinflammatory inteleukine-6 contents.

Sugar-Sweetened Beverages and Cardiometabolic Health: An Update of the Evidence

Sugar-sweetened beverages (SSBs) have little nutritional value and a robust body of evidence has linked the intake of SSBs to weight gain and risk of type 2 diabetes (T2D), cardiovascular disease (CVD), and some cancers. Metabolic Syndrome (MetSyn) is a clustering of risk factors that precedes the development of T2D and CVD; however, evidence linking SSBs to MetSyn is not clear. To make informed recommendations about SSBs, new evidence needs to be considered against existing literature. This review provides an update on the evidence linking SSBs and cardiometabolic outcomes including MetSyn. Findings from prospective cohort studies support a strong positive association between SSBs and weight gain and risk of T2D and coronary heart disease (CHD), independent of adiposity. Associations with MetSyn are less consistent, and there appears to be a sex difference with stroke with greater risk in women. Findings from short-term trials on metabolic risk factors provide mechanistic support for associations with T2D and CHD. Conclusive evidence from cohort studies and trials on risk factors support an etiologic role of SSB in relation to weight gain and risk of T2D and CHD. Continued efforts to reduce intake of SSB should be encouraged to improve the cardiometabolic health of individuals and populations.

Effects of coffee consumption on glucose metabolism: A systematic review of clinical trials

Epidemiological studies indicate an inverse association of coffee consumption with risk of type 2 diabetes mellitus. However, studies to determine the clinical effects of coffee consumption on the glucose metabolism biomarkers remain uncertain. The aim of this systematic review was to evaluate the effects of coffee consumption on glucose metabolism. A search of electronic databases (PubMed and Web of Science) was performed identifying studies published until September 2017. Eight clinical trials (n = 247 subjects) were identified for analyses. Participants and studies characteristics, main findings, and study quality (Jadad Score) were reported. Short-term (1-3 h) and long-term (2-16 weeks) studies were summarized separately. Short-term studies showed that consumption of caffeinated coffee may increase the area under the curve for glucose response, while for long-term studies, caffeinated coffee may improve the glycaemic metabolism by reducing the glucose curve and increasing the insulin response. The findings suggest that consumption of caffeinated coffee may lead to unfavourable acute effects; however, an improvement on glucose metabolism was found on long-term follow-up.

Coffee, caffeine, chlorogenic acid, and the purinergic system

Coffee is a drink prepared from roasted coffee beans and is lauded for its aroma and flavour. It is the third most popular beverage in the world. This beverage is known by its stimulant effect associated with the presence of methylxanthines. Caffeine, a purine-like molecule (1,3,7 trymetylxantine), is the most important bioactive compound in coffee, among others such as chlorogenic acid (CGA), diterpenes, and trigonelline. CGA is a phenolic acid with biological properties as antioxidant, anti-inflammatory, neuroprotector, hypolipidemic, and hypoglicemic. Purinergic system plays a key role inneuromodulation and homeostasis. Extracellular ATP, other nucleotides and adenosine are signalling molecules that act through their specific receptors, namely purinoceptors, P1 for nucleosides and P2 for nucleotides. They regulate many pathological processes, since adenosine, for instance, can limit the damage caused by ATP in the excitotoxicity from the neuronal cells. The primary purpose of this review is to discuss the effects of coffee, caffeine, and CGA on the purinergic system. This review focuses on the relationship/interplay between coffee, caffeine, CGA, and adenosine, and their effects on ectonucleotidases activities as well as on the modulation of P1 and P2 receptors from central nervous system and also in peripheral tissue.

The acute effect of coffee on endothelial function and glucose metabolism following a glucose load in healthy human volunteers

A diet rich in plant polyphenols has been suggested to reduce the incidence of cardiovascular disease and type 2 diabetes mellitus, in part, via improvements in endothelial function. Coffee is a rich source of phenolic compounds including the phenolic acid, chlorogenic acid (CGA). The aim of the study was to investigate the effect of coffee as a whole beverage on endothelial function, blood pressure and blood glucose concentration. Twelve healthy men and women were recruited to a randomised, placebo-controlled, cross-over study, with three treatments tested: (i) 18 g of ground caffeinated coffee containing 300 mg CGA in 200 mL of hot water, (ii) 18 g of decaffeinated coffee containing 287 mg CGA in 200 mL of hot water, and (iii) 200 mL of hot water (control). Treatment beverages were consumed twice, two hours apart, with the second beverage consumed simultaneously with a 75 g glucose load. Blood pressure was recorded and the finger prick glucose test was performed at time = 0 and then every 30 minutes up to 2 hours. Endothelial function, assessed using flow-mediated dilatation (FMD) of the brachial artery, was measured at 1 hour and a blood sample taken at 2 hours to measure plasma nitrate/nitrite and 5-CGA concentrations. The FMD response was significantly higher in the caffeinated coffee group compared to both decaffeinated coffee and water groups (P < 0.001). There was no significant difference in the FMD response between decaffeinated coffee and water. Blood glucose concentrations and blood pressure were not different between the three treatment groups. In conclusion, the consumption of caffeinated coffee resulted in a significant improvement in endothelial function, but there was no evidence for benefit regarding glucose metabolism or blood pressure. Although the mechanism has yet to be elucidated the results suggest that coffee as a whole beverage may improve endothelial function, or that caffeine is the component of coffee responsible for improving FMD.

Vanillic acid activates thermogenesis in brown and white adipose tissue

Anthocyanins have a positive effect on resistant obesity; however they cannot usually be absorbed directly but, instead, are metabolized by gut microbiota.

Coffee Consumption and the Risk of Obesity in Korean Women

Instant coffee mixes that contain sugar and non-dairy creamer account for 80-90% of the total coffee market in Korea. The objective of this study was to investigate the relationship between coffee consumption and obesity in Korean women. We included 5995 women who participated in a health screening examination at the Korean National Cancer Center between 2007 and 2016. Daily coffee consumption and the use of sugar and creamer in coffee was evaluated using a 106-item food frequency questionnaire. Obesity was assessed by body mass index (BMI), and abdominal obesity was assessed by waist circumference (WC). A multiple logistic regression model was used to calculate the odds ratio (OR) of obesity according to coffee consumption. After multivariate adjustment, high coffee consumption was positively associated with obesity as measured by BMI (≥3 cups vs. no drinks, OR = 2.52; 95% confidence interval (CI) = 1.91-3.34; p for the trend < 0.001) and abdominal obesity as measured by WC (≥3 cups vs. no drinks, OR = 2.11; 95% CI = 1.59-2.79; p for the trend < 0.001). The positive association between daily coffee consumption and obesity prevalence was not altered by menopause. The amount of coffee with additives consumed per day by Korean women was positively correlated with the prevalence of obesity, but causation cannot be determined due to the cross-sectional nature of the study design. The mechanism underlying the observed relationship is yet to be elucidated.

The potential effects of chlorogenic acid, the main phenolic components in coffee, on health: a comprehensive review of the literature

Chlorogenic acid (CGA), an important biologically active dietary polyphenol, is produced by certain plant species and is a major component of coffee. Reduction in the risk of a variety of diseases following CGA consumption has been mentioned in recent basic and clinical research studies. This systematic review discusses in vivo animal and human studies of the physiological and biochemical effects of chlorogenic acids (CGAs) on biomarkers of chronic disease. We searched PubMed, Embase, Amed and Scopus using the following search terms: ("chlorogenic acid" OR "green coffee bean extract") AND (human OR animal) (last performed on April 1st, 2015) for relevant literature on the in vivo effects of CGAs in animal and human models, including clinical trials on cardiovascular, metabolic, cancerogenic, neurological and other functions. After exclusion of editorials and letters, uncontrolled observations, duplicate and not relevant publications the remaining 94 studies have been reviewed. The biological properties of CGA in addition to its antioxidant and anti-inflammatory effects have recently been reported. It is postulated that CGA is able to exert pivotal roles on glucose and lipid metabolism regulation and on the related disorders, e.g. diabetes, cardiovascular disease (CVD), obesity, cancer, and hepatic steatosis. The wide range of potential health benefits of CGA, including its anti-diabetic, anti-carcinogenic, anti-inflammatory and anti-obesity impacts, may provide a non-pharmacological and non-invasive approach for treatment or prevention of some chronic diseases. In this study, the effects of CGAs on different aspects of health by reviewing the related literatures have been discussed.

Nonalcoholic steatohepatitis in morbid obese patients: coffee consumption vs. disease severity

INTRODUCTION

Obesity correlates with nonalcoholic fatty liver disease (NAFLD) and occurs in 90 to 100% of severely obese individuals (body mass index [BMI] > 35 kg/m2). Coffee consumption (CC) has been associated with reduced progression of fibrosis in both hepatitis C infection and NAFLD; however, this topic is still under discussion when this liver disease affects severely obese individuals.

OBJECTIVE

To assess the association between CC, insulin resistance (IR) and histological NAFLD morbid obese patients.

MATERIAL AND METHODS

Cross-sectional study, including obese individuals undergoing bariatric surgery, liver biopsy and histological diagnosis between September 2013 and August 2014. The patients were classified into 3 groups according to their weekly CC: 0- 239.9 mL; 240-2099.9 mL and ≥ 2100 mL.

RESULTS

A total of 112 obese individuals were included (BMI = 41.9 ± 4.3 kg/m2), with a mean age of 34.7 ± 7.4 years; 68.6% were women. CC was reported by 72.3% of patients. There were no statistical significant differences between groups regarding the presence of IR (84.8% vs. 74.2% vs. 75.9%; p = 0.536). Progressively higher percentages of individuals with normal liver histology were observed (14.7% vs. 21.9% vs. 24.3%). NASH (65.7% vs. 70.3% vs. 57.5%) were observed among those who consumed greater coffee volumes (p = 0.812). In conclusion, obese individuals with elevated CC exhibited lower frequencies of NASH, although with no statistical significance in this sample.

Computational analysis of the solvation of coffee ingredients in aqueous ionic liquid mixtures

In this paper, we investigate the solvation of coffee ingredients including caffeine, gallic acid as representative for phenolic compounds and quercetin as representative for flavonoids in aqueous mixtures of the ionic liquid 1-ethyl-3-methylimidazolium acetate [C2mim][OAc] at various concentrations. Due to the anisotropy of the solutes we show that classical Kirkwood-Buff theory is not appropriate to study solvation effects with increasing ionic liquid content. However, excess coordination numbers as well as the mean residence time of solvent molecules at the surface of the solutes can be determined by Voronoi tessellation. Since the volume of the hydration shells is also available by this method, solvation free energies will be discussed as a function of the ionic liquid concentration to yield a physical meaningful picture of solvation for the anisotropic solutes. Hydrogen bonding capabilities of the solutes and their relevance for experimental extraction yields from spent coffee grounds are also discussed.

Guest-matrix interactions affect the solvation of cyclodextrin-based polymeric hydrogels: a UV Raman scattering study

The focus of the present work is to shed light on possible modifications of the molecular properties of polysaccharide hydrogels induced by the establishment of specific non-covalent interactions during the loading of a guest compound inside the gel phase. With this aim, a case study of the encapsulation of caffeine (Caf) inside cyclodextrin-based hydrogels, namely, cyclodextrin nanosponges (NS), is systematically investigated here by using UV Raman scattering experiments. The UV Raman spectra of the hydrogels, analysed as a function of temperature, concentration of the guest molecule loaded in the gel phase and pH, prove particularly informative both on the structural rearrangements of the hydrophobic/hydrophilic groups of the polymeric network and on the breaking/formation of specific guest-matrix interactions. Analysis of the temperature dependence of dynamical parameters, i.e., the dephasing time associated with specific vibrational modes of the polymer backbone, enables the proposal of a molecular picture in which the loading of Caf in NS hydrogels tends to favour access of the water solvent to the more hydrophobic portions of the polymer matrix, which is in turn reflected in a marked increase in the solvation of the whole system. The achievements of this work appear of interest with respect to the design of new possible strategies for controlling the diffusion/release of bioactive molecules inside hydrogel networks, besides corroborating the potential of UV Raman scattering experiments to give new molecular insights into complex phenomena affecting hydrogel phases.

Effects of Caffeine and Lycopene in Experimentally Induced Diabetes Mellitus

OBJECTIVES

Diabetes mellitus (DM) is a global epidemic with increasing prevalence. The disease is chronic in nature, and patients must use antidiabetic drugs or insulin during their lifespan. Because of the difficulty of using injectable insulin preparations, patients and practitioners prefer to use oral antidiabetic drugs for prophylaxis and treatment. There are, however, numerous adverse effects of antidiabetic drugs and rapidly increasing attention is being paid to new nutraceutical drugs with fewer adverse effects. The purpose of this study was to evaluate the effects of caffeine and lycopene on streptozotocin (STZ)-induced DM in rats.

METHODS

Caffeine and lycopene were administered to the study groups by oral gavages for 1 month whereafter experimental diabetes was induced in 90 rats in 6 groups.

RESULTS

There were no pathological effects of lycopene and caffeine on the pancreas. Marked vacuolization and degeneration were observed in STZ-treated groups. Caffeine and lycopene decreased the pathological findings and lowered the blood and urine glucose levels in the rats with STZ-induced DM, whereas these compounds increased serum insulin levels.

CONCLUSIONS

This study showed that caffeine and lycopene provided protective effects against experimentally induced DM. The protective effects of lycopene were observed to be much greater than those of caffeine.

Fructose and Cardiometabolic Health: What the Evidence From Sugar-Sweetened Beverages Tells Us

Recent attention has focused on fructose as having a unique role in the pathogenesis of cardiometabolic diseases. However, because we rarely consume fructose in isolation, the major source of fructose in the diet comes from fructose-containing sugars, sucrose and high fructose corn syrup, in sugar-sweetened beverages and foods. Intake of sugar-sweetened beverages has been consistently linked to increased risk of obesity, type 2 diabetes, and cardiovascular disease in various populations. Putative underlying mechanisms include incomplete compensation for liquid calories, adverse glycemic effects, and increased hepatic metabolism of fructose leading to de novo lipogenesis, production of uric acid, and accumulation of visceral and ectopic fat. In this review we summarize the epidemiological and clinical trial evidence evaluating added sugars, especially sugar-sweetened beverages, and the risk of obesity, diabetes, and cardiovascular disease and address potential biological mechanisms with an emphasis on fructose physiology. We also discuss strategies to reduce intake of fructose-containing beverages.

Stacking of purines in water: the role of dipolar interactions in caffeine

Concentration dependence of the NCE and the dephasing time show that caffeine molecules aggregate at 80 °C by planar stacking with a relevant contribution of dipole interactions.

Antidiabetic Effects of Simple Phenolic Acids: A Comprehensive Review

Diabetes mellitus (DM) has become a major public health threat across the globe. Current antidiabetic therapies are based on synthetic drugs that very often have side effects. It has been widely acknowledged that diet plays an important role in the management of diabetes. Phenolic acids are widely found in daily foods such as fruits, vegetables, cereals, legumes, and wine and they provide biological, medicinal, and health properties. Simple phenolic acids have been shown to increase glucose uptake and glycogen synthesis, improve glucose and lipid profiles of certain diseases (obesity, cardiovascular diseases, DM, and its complication). The current review is an attempt to list out the antidiabetic effects of simple phenolic acids from medicinal plants and botanical foods.

Methodological and metabolic considerations in the study of caffeine-containing energy drinks

Caffeine-containing energy drinks are popular and widely available beverages. Despite large increases in consumption, studies documenting the nutritional, metabolic, and health implications of these beverages are limited. This review provides some important methodological considerations in the examination of these drinks and highlights their potential impact on the gastrointestinal system, liver, and metabolic health. The gastrointestinal system is important as it comes into contact with the highest concentration of energy drink ingredients and initiates a chain of events to communicate with peripheral tissues. Although energy drinks have diverse compositions, including taurine, ginseng, and carnitine, the most metabolically deleterious ingredients appear to be simple sugars (such as glucose and fructose) and caffeine. In combination, these last two ingredients have the greatest metabolic impact and potential influence on overall health.

Performance effects and metabolic consequences of caffeine and caffeinated energy drink consumption on glucose disposal

This review documents two opposing effects of caffeine and caffeine-containing energy drinks, i.e., their positive effects on athletic performance and their negative impacts on glucose tolerance in the sedentary state. Analysis of studies examining caffeine administration prior to performance-based exercise showed caffeine improved completion time by 3.6%. Similar analyses following consumption of caffeine-containing energy drinks yielded positive, but more varied, benefits, which were likely due to the diverse nature of the studies performed, the highly variable composition of the beverages consumed, and the range of caffeine doses administered. Conversely, analyses of studies administering caffeine prior to either an oral glucose tolerance test or insulin clamp showed a decline in whole-body glucose disposal of ~30%. The consequences of this resistance are unknown, but there may be implications for the development of a number of chronic diseases. Both caffeine-induced performance enhancement and insulin resistance converge with the primary actions of caffeine on skeletal muscle.

Inhibitory activities of caffeoylquinic acid derivatives from Ilex kudingcha C.J. Tseng on α-glucosidase from Saccharomyces cerevisiae

Polyphenols and caffeoylquinic acid (CQA) derivatives (3-CQA, 4-CQA, 5-CQA, 3,4-diCQA, 3,5-diCQA, and 4,5-diCQA) were prepared from Ilex kudingcha C.J. Tseng, and their effects and mechanisms on the activities of α-glucosidase from Saccharomyces cerevisiae were investigated in the present study. As results, the IC50 values for CQA derivatives were 0.16-0.39 mg/mL, and the inhibition mode of CQA derivatives was noncompetitive. On the basis of fluorescence spectroscopy and circular dichroism spectroscopy data, the binding constants and number of binding sites were calculated to be 10(6)-10(8) M(-1) and 1.42-1.87, respectively. CQA derivatives could bind to the enzyme mainly through hydrophobic interaction, altering the microenvironment and molecular conformation of the enzyme, thus decreasing the catalytic activity. To the authors' knowledge, this is the first report on α-glucosidase inhibitory mechanism by CQA derivatives from I. kudingcha, and the findings suggest a potential use of kudingcha as functional foods for the prevention and treatment of diabetes and related symptoms.

Instant coffee consumption may be associated with higher risk of metabolic syndrome in Korean adults

AIMS

Cumulative evidence suggests that coffee consumption may have beneficial effects on metabolic diseases; however, few previous studies have considered the types of coffee consumed and the additives used. We investigated the relationship between coffee consumption and metabolic syndrome (MetSyn) and its components.

METHODS

We analyzed 17,953 Korean adults, aged 19-65 years, using cross-sectional data from the Korean National Health and Nutrition Examination Survey (KNHANES, 2007-2011). Coffee consumption level, types of coffee consumed, and the additives used were assessed based on a food frequency questionnaire and 24-h recall. Demographic and lifestyle factors were assessed using self-administered questionnaires. Data on metabolic biomarkers were obtained from a health examination. Multivariable logistic regression was used to determine the odds ratios of prevalent metabolic syndrome and its components according to frequency and type of coffee consumption.

RESULTS

We found that 76% of the subjects were habitual coffee drinkers, most of whom consumed instant coffee mix containing sugar and powder creamer. After multivariable adjustment, the odds ratios (95% CI) comparing those who consumed coffee ≥3 times/day with those who consumed coffee <1 time/week were 1.37 (1.15-1.63) for obesity, 1.33 (1.11-1.59) for abdominal obesity, 1.28 (1.09-1.51) for hypo-HDL cholesterolemia, and 1.37 (1.10-1.72) for metabolic syndrome. Instant-coffee drinkers were observed to have elevated risks of these metabolic conditions.

CONCLUSIONS

Consumption of coffee, particularly instant coffee mix, may have harmful effects on MetSyn, perhaps partly deriving from excessive intake of sugar and powder creamer.

Chlorogenic acid improves high fat diet-induced hepatic steatosis and insulin resistance in mice

PURPOSE

Chlorogenic acid (CGA), the most abundant component in coffee, has exhibited many biological activities. The objective of this study is to assess preventive and therapeutic effects of CGA on obesity and obesity-related liver steatosis and insulin resistance.

METHODS

Two sets of experiments were conducted. In set 1, 6-week old C57BL/6 mice were fed a regular chow or high-fat diet (HFD) for 15 weeks with twice intra-peritoneal (IP) injection of CGA (100 mg/kg) or DMSO (carrier solution) per week. In set 2, obese mice (average 50 g) were treated by CGA (100 mg/kg, IP, twice weekly) or DMSO for 6 weeks. Body weight, body composition and food intake were monitored. Blood glucose, insulin and lipid levels were measured at end of the study. Hepatic lipid accumulation and glucose homeostasis were evaluated. Additionally, genes involved in lipid metabolism and inflammation were analyzed by real time PCR.

RESULTS

CGA significantly blocked the development of diet-induced obesity but did not affect body weight in obese mice. CGA treatment curbed HFD-induced hepatic steatosis and insulin resistance. Quantitative PCR analysis shows that CGA treatment suppressed hepatic expression of Pparγ, Cd36, Fabp4, and Mgat1 gene. CGA treatment also attenuated inflammation in the liver and white adipose tissue accompanied by a decrease in mRNA levels of macrophage marker genes including F4/80, Cd68, Cd11b, Cd11c, and Tnfα, Mcp-1 and Ccr2 encoding inflammatory proteins.

CONCLUSION

Our study provides direct evidence in support of CGA as a potent compound in preventing diet-induced obesity and obesity-related metabolic syndrome. Our results suggest that drinking coffee is beneficial in maintaining metabolic homeostasis when on a high fat diet.

Chlorogenic acid improves high fat diet-induced hepatic steatosis and insulin resistance in mice

PURPOSE

Chlorogenic acid (CGA), the most abundant component in coffee, has exhibited many biological activities. The objective of this study is to assess preventive and therapeutic effects of CGA on obesity and obesity-related liver steatosis and insulin resistance.

METHODS

Two sets of experiments were conducted. In set 1, 6-week old C57BL/6 mice were fed a regular chow or high-fat diet (HFD) for 15 weeks with twice intra-peritoneal (IP) injection of CGA (100 mg/kg) or DMSO (carrier solution) per week. In set 2, obese mice (average 50 g) were treated by CGA (100 mg/kg, IP, twice weekly) or DMSO for 6 weeks. Body weight, body composition and food intake were monitored. Blood glucose, insulin and lipid levels were measured at end of the study. Hepatic lipid accumulation and glucose homeostasis were evaluated. Additionally, genes involved in lipid metabolism and inflammation were analyzed by real time PCR.

RESULTS

CGA significantly blocked the development of diet-induced obesity but did not affect body weight in obese mice. CGA treatment curbed HFD-induced hepatic steatosis and insulin resistance. Quantitative PCR analysis shows that CGA treatment suppressed hepatic expression of Pparγ, Cd36, Fabp4, and Mgat1 gene. CGA treatment also attenuated inflammation in the liver and white adipose tissue accompanied by a decrease in mRNA levels of macrophage marker genes including F4/80, Cd68, Cd11b, Cd11c, and Tnfα, Mcp-1 and Ccr2 encoding inflammatory proteins.

CONCLUSION

Our study provides direct evidence in support of CGA as a potent compound in preventing diet-induced obesity and obesity-related metabolic syndrome. Our results suggest that drinking coffee is beneficial in maintaining metabolic homeostasis when on a high fat diet.

Do sugar-sweetened beverages cause adverse health outcomes in adults? A systematic review protocol

BACKGROUND

Chronic diseases, such as cardiovascular disease and type 2 diabetes, impose significant burden to public health. Most chronic diseases are associated with underlying preventable risk factors, such as elevated blood pressure, blood glucose, and lipids, physical inactivity, excessive sedentary behaviours, overweight and obesity, and tobacco usage. Sugar-sweetened beverages are known to be significant sources of additional caloric intake, and given recent attention to their contribution in the development of chronic diseases, a systematic review is warranted. We will assess whether the consumption of sugar-sweetened beverages in adults is associated with adverse health outcomes and what the potential moderating factors are.

METHODS/DESIGN

Of interest are studies addressing sugar-sweetened beverage consumption, taking a broad perspective. Both direct consumption studies as well as those evaluating interventions that influence consumption (e.g. school policy, educational) will be relevant. Non-specific or multi-faceted behavioural, educational, or policy interventions may also be included subject to the level of evidence that exists for the other interventions/exposures. Comparisons of interest and endpoints of interest are pre-specified. We will include randomized controlled trials, controlled clinical trials, interrupted time series studies, controlled before-after studies, prospective and retrospective comparative cohort studies, case-control studies, and nested case-control designs. The MEDLINE, Embase, The Cochrane Library, CINAHL, ERIC, and PsycINFO databases and grey literature sources will be searched. The processes for selecting studies, abstracting data, and resolving conflicts are described. We will assess risk of bias using design-specific tools. To determine sets of confounding variables that should be adjusted for, we have developed causal directed acyclic graphs and will use those to inform our risk of bias assessments. Meta-analysis will be conducted where appropriate; parameters for exploring statistical heterogeneity and effect modifiers are pre-specified. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach will be used for determining the quality of evidence for outcomes.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42014009638.

Do sugar-sweetened beverages cause adverse health outcomes in children? A systematic review protocol

BACKGROUND

Cardiovascular disease and type 2 diabetes are examples of chronic diseases that impose significant morbidity and mortality in the general population worldwide. Most chronic diseases are associated with underlying preventable risk factors, such as elevated blood pressure, high blood glucose or glucose intolerance, high lipid levels, physical inactivity, excessive sedentary behaviours, and overweight/obesity. The occurrence of intermediate outcomes during childhood increases the risk of disease in adulthood. Sugar-sweetened beverages are known to be significant sources of additional caloric intake, and given recent attention to their contribution in the development of chronic diseases, a systematic review is warranted. We will assess whether the consumption of sugar-sweetened beverages in children is associated with adverse health outcomes and what the potential moderating factors are.

METHODS/DESIGN

Of interest are studies addressing sugar-sweetened beverage consumption, taking a broad perspective. Both direct consumption studies as well as those evaluating interventions that influence consumption (e.g. school policy, educational) will be relevant. Non-specific or multi-faceted behavioural, educational, or policy interventions may also be included subject to the level of evidence that exists for the other interventions/exposures. Comparisons of interest and endpoints of interest are pre-specified. We will include randomized controlled trials, controlled clinical trials, interrupted time series studies, controlled before-after studies, prospective and retrospective comparative cohort studies, case-control studies, and nested case-control designs. The MEDLINE®, Embase, The Cochrane Library, CINAHL, ERIC, and PsycINFO® databases and grey literature sources will be searched. The processes for selecting studies, abstracting data, and resolving conflicts are described. We will assess risk of bias using design-specific tools. To determine sets of confounding variables that should be adjusted for, we have developed causal directed acyclic graphs and will use those to inform our risk of bias assessments. Meta-analysis will be conducted where appropriate; parameters for exploring statistical heterogeneity and effect modifiers are pre-specified. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach will be used to determine the quality of evidence for outcomes.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42014009641.

Validation of caffeine dehydrogenase from Pseudomonas sp. strain CBB1 as a suitable enzyme for a rapid caffeine detection and potential diagnostic test

Excess consumption of caffeine (>400 mg/day/adult) can lead to adverse health effects. Recent introduction of caffeinated products (gums, jelly beans, energy drinks) might lead to excessive consumption, especially among children and nursing mothers, hence attracting the Food and Drug Administration's attention and product withdrawals. An "in-home" test will aid vigilant consumers in detecting caffeine in beverages and milk easily and quickly, thereby restricting its consumption. Known diagnostic methods lack speed and sensitivity. We report a caffeine dehydrogenase (Cdh)-based test which is highly sensitive (1-5 ppm) and detects caffeine in beverages and mother's milk in 1 min. Other components in these complex test samples do not interfere with the detection. Caffeine-dependent reduction of the dye iodonitrotetrazolium chloride results in shades of pink proportional to the levels in test samples. This test also estimates caffeine levels in pharmaceuticals, comparable to high-performance liquid chromatography. The Cdh-based test is the first with the desired attributes of a rapid and robust caffeine diagnostic kit.

New biomarkers of coffee consumption identified by the non-targeted metabolomic profiling of cohort study subjects

Coffee contains various bioactives implicated with human health and disease risk. To accurately assess the effects of overall consumption upon health and disease, individual intake must be measured in large epidemiological studies. Metabolomics has emerged as a powerful approach to discover biomarkers of intake for a large range of foods. Here we report the profiling of the urinary metabolome of cohort study subjects to search for new biomarkers of coffee intake. Using repeated 24-hour dietary records and a food frequency questionnaire, 20 high coffee consumers (183–540 mL/d) and 19 low consumers were selected from the French SU.VI.MAX2 cohort. Morning spot urine samples from each subject were profiled by high-resolution mass spectrometry. Partial least-square discriminant analysis of multidimensional liquid chromatography-mass spectrometry data clearly distinguished high consumers from low via 132 significant (p-value<0.05) discriminating features. Ion clusters whose intensities were most elevated in the high consumers were annotated using online and in-house databases and their identities checked using commercial standards and MS-MS fragmentation. The best discriminants, and thus potential markers of coffee consumption, were the glucuronide of the diterpenoid atractyligenin, the diketopiperazine cyclo(isoleucyl-prolyl), and the alkaloid trigonelline. Some caffeine metabolites, such as 1-methylxanthine, were also among the discriminants, however caffeine may be consumed from other sources and its metabolism is subject to inter-individual variation. Receiver operating characteristics curve analysis showed that the biomarkers identified could be used effectively in combination for increased sensitivity and specificity. Once validated in other cohorts or intervention studies, these specific single or combined biomarkers will become a valuable alternative to assessment of coffee intake by dietary survey and finally lead to a better understanding of the health implications of coffee consumption.

Coffee and non-alcoholic fatty liver disease: brewing evidence for hepatoprotection?

Coffee is one of the most popular beverages in the world. Several studies consistently show that coffee drinkers with chronic liver disease have a reduced risk of cirrhosis and a lower incidence of hepatocellular carcinoma regardless of primary etiology. With the increasing prevalence of non-alcoholic fatty liver disease (NAFLD) worldwide, there is renewed interest in the effect of coffee intake on NAFLD severity and positive clinical outcomes. This review gives an overview of growing epidemiological and clinical evidence which indicate that coffee consumption reduces severity of NAFLD. These studies vary in methodology, and potential confounding factors have not always been completely excluded. However, it does appear that coffee, and particular components other than caffeine, reduce NAFLD prevalence and inflammation of non-alcoholic steatohepatitis. Several possible mechanisms underlying coffee's hepatoprotective effects in NAFLD include antioxidative, anti-inflammatory, and antifibrotic effects, while a chemopreventive effect against hepatocarcinogenesis seems likely. The so-far limited data supporting such effects will be discussed, and the need for further study is highlighted.

Caffeinated and decaffeinated coffee consumption and risk of type 2 diabetes: a systematic review and a dose-response meta-analysis

OBJECTIVE

Previous meta-analyses identified an inverse association of coffee consumption with the risk of type 2 diabetes. However, an updated meta-analysis is needed because new studies comparing the trends of association for caffeinated and decaffeinated coffee have since been published.

RESEARCH DESIGN AND METHODS

PubMed and Embase were searched for cohort or nested case-control studies that assessed the relationship of coffee consumption and risk of type 2 diabetes from 1966 to February 2013. A restricted cubic spline random-effects model was used.

RESULTS

Twenty-eight prospective studies were included in the analysis, with 1,109,272 study participants and 45,335 cases of type 2 diabetes. The follow-up duration ranged from 10 months to 20 years. Compared with no or rare coffee consumption, the relative risk (RR; 95% CI) for diabetes was 0.92 (0.90-0.94), 0.85 (0.82-0.88), 0.79 (0.75-0.83), 0.75 (0.71-0.80), 0.71 (0.65-0.76), and 0.67 (0.61-0.74) for 1-6 cups/day, respectively. The RR of diabetes for a 1 cup/day increase was 0.91 (0.89-0.94) for caffeinated coffee consumption and 0.94 (0.91-0.98) for decaffeinated coffee consumption (P for difference = 0.17).

CONCLUSIONS

Coffee consumption was inversely associated with the risk of type 2 diabetes in a dose-response manner. Both caffeinated and decaffeinated coffee was associated with reduced diabetes risk.