Cafestol and kahweol, two coffee specific diterpenes with anticarcinogenic activity

Terpenoids as Potential Geroprotectors

Terpenes and terpenoids are the largest groups of plant secondary metabolites. However, unlike polyphenols, they are rarely associated with geroprotective properties. Here we evaluated the conformity of the biological effects of terpenoids with the criteria of geroprotectors, including primary criteria (lifespan-extending effects in model organisms, improvement of aging biomarkers, low toxicity, minimal adverse effects, improvement of the quality of life) and secondary criteria (evolutionarily conserved mechanisms of action, reproducibility of the effects on different models, prevention of age-associated diseases, increasing of stress-resistance). The number of substances that demonstrate the greatest compliance with both primary and secondary criteria of geroprotectors were found among different classes of terpenoids. Thus, terpenoids are an underestimated source of potential geroprotectors that can effectively influence the mechanisms of aging and age-related diseases.

New trends in coffee diterpenes research from technological to health aspects

The coffee oil is rich in diterpenes, mainly cafestol and kahweol, which are predominantly present in the esterified form with different fatty acids. Despite their beneficial effects including anti-angiogenic and anti-carcinogenic properties, they have been also associated with negative consequences such as elevation of blood cholesterol. Considering the coffee, it is an important human beverage with biological effects, including potentially health benefits or risks. Therefore, it may have important public health implications due to its widespread massive consumption, with major incidence in the varieties Arabica and Robusta. According to literatures, cafestol (182-1308 mg/100 g), kahweol (0-1265 mg/100 g) and 16-O-methycafestol (0-223 mg/100 g) are the main diterpenes in green and roasted coffee beans. Nevertheless, the coffee species, genetic background, and technological parameters like roasting and brewing have a clear effect on coffee diterpene content. Besides that, bibliographic data indicated that limited studies have specifically addressed the recent analytical techniques used for determination of this class of compounds, being HPLC and GC the most common approaches. For these reasons, this review aimed to actualize the occurrence and the profile of diterpenes in coffee matrices, focusing on the effect of species, roasting and brewing and on the other hand, introduce the current state on knowledge regarding coffee diterpenes determination which are nowadays highly regarded and widely used. In general, since diterpenes exhibit different health effects depending on their consumption dosage, several parameters needs to be carefully analyzed and considered when comparing the results.

Chemical composition and health properties of coffee and coffee by-products

Coffee can be an ally in the fight against diseases such as type 2 diabetes, cancer, hepatic injury, cirrhosis, depression, suicidal behavior, and neurological and cardiovascular disorders. The properties of coffee also favor gastrointestinal tract and gut microbiota establishment. Coffee bioactive components include phenolic compounds (chlorogenic acids, cafestol and kahweol), alkaloids (caffeine and trigonelin), diterpenes (cafestol and kahweol) and other secondary metabolites. The image of coffee as a super functional food has helped to increase coffee consumption across the globe. This chapter addresses the main health promotion mechanisms associated with coffee consumption. Related topics on coffee production chain, world consumption and reuse of coffee by-products in the production of high-value-adding molecules with potential applications in the food industry are addressed and discussed.

Acute and subacute (28 days) toxicity of green coffee oil enriched with diterpenes cafestol and kahweol in rats

Green coffee oil enriched with cafestol and kahweol was obtained by supercritical fluid extraction using carbon dioxide while its safety and possible effects from acute and subacute treatment were evaluated in rats. For acute toxicity study, single dose of green coffee oil (2000 mg/kg) was administered by gavage in female rats. For subacute study (28 days), 32 male rats received different doses of green coffee oil extract (25, 50, and 75 mg/kg/day). In the acute toxicity study, main findings of this treatment indicated no mortality, body weight decrease, no changes in hematological and biochemical parameters, and relative weight increase in heart and thymus, without histopathological alterations in all assessed organs. All these findings suggest that LD₅₀ is higher than aforesaid dose. In the subacute toxicity, main findings showed body weight decrease mainly at the highest dose without food consumption change, serum glucose and tryglicerides levels decrease, and relative weight increase in liver. As evidenced in histopathological pictures, no changes were observed at all treated doses. Our study suggest that green coffee oil can be explored to clinically develop new hypocholesteromic and hypoglycemic agents. However, further studies evaluating long-term effects are needed in order to have sufficient safety evidence for its use in humans.

Association between coffee consumption and overall risk of being diagnosed with or dying from cancer among >300 000 UK Biobank participants in a large-scale Mendelian randomization study

BACKGROUND

Previous observational studies have suggested that coffee intake may be associated with a reduction in cancer risk. Mendelian randomization (MR) studies can help clarify whether the observed associations are likely to be causal. Here we evaluated whether coffee intake is associated with: (i) overall risk of being diagnosed with/dying from any cancer; and (ii) risk of individual cancers.

METHODS

We identified 46 155 cases (of which 6998 were fatal) and 270 342 controls of White British ancestry from the UK Biobank cohort (UKB), based on ICD10 diagnoses. Individuals with benign tumours were excluded. Coffee intake was self-reported and recorded based on cup/day consumption. We conducted both observational and summary data MR analyses.

RESULTS

There was no observational association between coffee intake and overall cancer risk [odds ratio (OR) per one cup/day increase = 0.99, 95% confidence interval (CI) 0.98, 1.00] or cancer death (OR = 1.01, 0.99, 1.03); the estimated OR from MR is 1.01 (0.94, 1.08) for overall cancer risk and 1.11 (0.95, 1.31) for cancer death. The relationship between coffee intake and individual cancer risks were consistent with a null effect, with most cancers showing little or no associations with coffee. Meta-analysis of our MR findings with publicly available summary data on various cancers do not support a strong causal relationship between coffee and risk of breast, ovarian, lung or prostate cancer, upon correction for multiple testing.

CONCLUSIONS

Taken together, coffee intake is not associated with overall risk of being diagnosed with or dying from cancer in UKB. For individual cancers, our findings were not statistically inconsistent with earlier observational studies, although for these we were unable to rule out a small effect on specific types of cancer.

Association between coffee consumption and risk of bladder cancer in a meta-analysis of 16 prospective studies

Background

Current evidence remains equivocal as to whether and how consumption of coffee may be associated with risk of bladder cancer, and potential influence of confounding by smoking on this association is yet to be elucidated. We conducted an updated meta-analysis of prospective studies to address these issues.

Methods

Relevant studies were identified by searching PubMed and EMBASE databases from inception to April 2019. A random-effects model was used to estimate summary relative risk (RR) with corresponding 95% confidence interval (CI) of bladder cancer associated with coffee consumption.

Results

The final analysis included 16 prospective studies comprising 2,122,816 participants and 11,848 bladder cancer cases. Overall, coffee consumption was not associated with risk of bladder cancer (RR _high-vs-low = 1.07, 95% CI: 0.96–1.20). The lack of association persisted in the strata defined by sex or participants’ smoking status. Meta-regression analyses identified the number cases (P_difference = 0.06) and the degree of adjustment for smoking (P_difference = 0.04) as potential sources of heterogeneity. There was an increased risk of bladder cancer related to higher coffee consumption among studies with fewer cases (RR _high-vs-low = 1.38, 95% CI: 1.05–1.81) and among those with poorer adjustment for smoking (RR _high-vs-low = 1.48, 95% CI: 1.14–1.93). Results were similar in the dose-response analyses (RR _{1 cup/d} = 1.01, 95% CI: 0.98–1.03).

Conclusion

Best evidence available to date does not support an independent association between coffee consumption and bladder cancer risk. Some direct associations observed in individual studies may be a result of residual confounding by smoking.

Supplementary information

Supplementary information accompanies this paper at 10.1186/s12986-019-0390-3.

Associations between Coffee Products and Breast Cancer Risk: a Case-Control study in Hong Kong Chinese Women

Coffee contains caffeine and diterpenes that were associated with decreased breast cancer risk, but results remained inconsistent. The study purpose was to investigate the associations between coffee products and breast cancer risk among Hong Kong Chinese women. We conducted a hospital-based case-control study in three public hospitals. 2169 Chinese women aged 24-84 years old were interviewed using a standardized questionnaire with questions asking types, cups and duration on coffee drinking. We used unconditional multivariate logistic regression to calculate the adjusted odds ratio (AOR) and 95% confidence interval (95% CI) for breast cancer risk with different coffee products. 238 (20.6%) cases and 179 (17.7%) controls are habitual coffee drinkers. No association was found between overall coffee drinking and breast cancer risk. Compared to the non-habitual coffee drinkers, women who consumed instant coffee (AOR = 1.50, 95% CI = 1.10-2.03) were significantly associated with an increased breast cancer risk. Women who drank brewed coffee (AOR = 0.48, 95% CI = 0.28-0.82) were negatively associated with breast cancer risk. A positive association between instant coffee and breast cancer risk was observed, contradicted to the outcomes of drinking brewed coffee. Larger studies are warranted to ascertain the role of different types of coffee products in breast cancer risk.

Cafestol and Kahweol: A Review on Their Bioactivities and Pharmacological Properties

Cafestol and kahweol are natural diterpenes extracted from coffee beans. In addition to the effect of raising serum lipid, in vitro and in vivo experimental results have revealed that the two diterpenes demonstrate multiple potential pharmacological actions such as anti-inflammation, hepatoprotective, anti-cancer, anti-diabetic, and anti-osteoclastogenesis activities. The most relevant mechanisms involved are down-regulating inflammation mediators, increasing glutathione (GSH), inducing apoptosis of tumor cells and anti-angiogenesis. Cafestol and kahweol show similar biological activities but not exactly the same, which might due to the presence of one conjugated double bond on the furan ring of the latter. This review aims to summarize the pharmacological properties and the underlying mechanisms of cafestol-type diterpenoids, which show their potential as functional food and multi-target alternative medicine.

Common habitual behaviors and synchronous colorectal cancer risk: a retrospective case-control study

PURPOSE

The association of habitual behaviors with the prevalence of synchronous colorectal cancer (sCRC) is unknown. Here, we investigated whether these behaviors, which are known risk factors for colorectal polyps, may be related to sCRC risk.

METHODS

We enrolled 17,093 patients who underwent cancer treatment between January 1995 and December 2016 and examined the association of age, sex, familial history of hereditary colorectal cancer (CRC), and status of three common habitual behaviors (smoking and alcohol and coffee consumption) with the prevalence of sCRC.

RESULTS

Of the enrolled patients, 960 (5.6%) patients had sCRC. The independent risk factors for sCRC prevalence included advanced age, male sex, hereditary CRC, smoking, and daily alcohol consumption of more than one bottle (> 600 mL). Contrary to these factors, daily coffee consumption of more than one cup seemed to provide a protection from sCRC. In the Kaplan-Meier test, the significantly worse 5-year overall survival (OS) was noted in smokers with stage 0-III CRC. The effect of alcohol consumption on 5-year OS was significant in stages II and III. Compared with those without daily coffee consumption, patients with daily coffee consumption had significantly higher 5-year OS in stages I (93.0% vs. 86.4%), II (87.1% vs. 77.2%), III (71.5% vs. 61.9%), and IV (18.0% vs. 13.0%).

CONCLUSIONS

sCRC prevalence was significantly associated with habitual behaviors. Patients with smoking or with daily alcohol consumption of one bottle had higher sCRC prevalence than did those without these habits. Coffee consumption could be a protective factor for lowering sCRC risk.

Dose-response meta-analysis of coffee consumption and risk of colorectal adenoma

BACKGROUND

The association between coffee and colorectal adenoma risk remains controversial. We conducted a meta-analysis of cohort and case-control studies to sum up the existing proof about this matter.

METHODS

We searched Pubmed, Medline, and Embase for studies published before 1 September 2018 on coffee consumption and colorectal adenoma in any language. The different ORs were calculated for cohort and case-control studies in this study, and we use a random-effects model to aggregate the relative risks of individual studies and conduct dose response, heterogeneity, and publication bias.

RESULTS

A total of 8 studies (6 case-control studies, 2 cohort studies) were identified, including 7090 subjects. In a summary analysis of all studies, high coffee intake (compared the highest with the lowest categories) was associated with a reduced risk of colorectal adenoma (odds ratio [OR] = 0.70, 95% confidence interval [CI] = 0.55-0.90). The results of subgroup analysis of adenoma location were similar with the pooled analysis, except for rectal adenoma. In the dose-response meta-analysis study, the estimated total odds ratio for increasing coffee consumption by 150 ml per day (about one cup) was 0.91 (95% CI = 0.87-0.95).

CONCLUSIONS

The meta-analysis demonstrates possible evidence that increased coffee intake is related to a reduced risk of colon adenoma. However, because of latent confusion and different exposure classification, this finding should be carefully considered.

The association between coffee consumption and bladder cancer in the bladder cancer epidemiology and nutritional determinants (BLEND) international pooled study

Background

Inconsistent results for coffee consumption and bladder cancer (BC) risk have been shown in epidemiological studies. This research aims to increase the understanding of the association between coffee consumption and BC risk by bringing together worldwide case–control studies on this topic.

Methods

Data were collected from 13 case–control comprising of 5,911 cases and 16,172 controls. Pooled multivariate odds ratios (ORs), with corresponding 95% confidence intervals (CIs), were obtained using multilevel logistic regression models. Furthermore, linear dose–response relationships were examined using fractional polynomial models.

Results

No association of BC risk was observed with coffee consumption among smokers. However, after adjustment for age, gender, and smoking, the risk was significantly increased for never smokers (ever vs. never coffee consumers: OR_model2 1.30, 95% CI 1.06–1.59; heavy (> 4 cups/day) coffee consumers vs. never coffee consumers: OR_model2 1.52, 95% CI 1.18–1.97, p trend = 0.23). In addition, dose–response analyses, in both the overall population and among never smokers, also showed a significant increased BC risk for coffee consumption of more than four cups per day. Among smokers, a significant increased BC risk was shown only after consumption of more than six cups per day.

Conclusion

This research suggests that positive associations between coffee consumption and BC among never smokers but not smokers.

Association between coffee intake and the risk of oral cavity cancer: a meta-analysis of observational studies

The association between coffee intake and the risk of oral cavity cancer has been inconsistent in previous studies. Therefore, we conducted a meta-analysis to summarize the evidence regarding the strength of association between coffee intake and oral cavity cancer. PubMed, Embase, and Cochrane Library were searched to select studies on the relationship between coffee intake and oral cavity cancer conducted up to September 2018. Case-control or cohort studies and those that have reported about the effect estimates with 95% confidence intervals (CIs) of oral cavity cancer according to the different categories of coffee intake were included. The odds ratio (OR) and its corresponding 95% CI were calculated using the random-effects model. Fourteen case-control and five cohort studies that recruited 6456 patients with oral cavity cancer were included in the final quantitative meta-analysis. High versus low coffee intake was associated with a reduced risk of oral cavity cancer (OR: 0.68; 95% CI: 0.56-0.82; P < 0.001) in case-control studies (OR: 0.70; 95% CI: 0.55-0.90; P = 0.006) and cohort studies (OR: 0.65; 95% CI: 0.48-0.87; P = 0.004). Moreover, intermediate coffee intake was significantly associated with a reduced risk of oral cavity cancer (OR: 0.85; 95% CI: 0.77-0.94; P = 0.002), and such associations were mainly observed in case-control studies (OR: 0.86; 95% CI: 0.76-0.98; P = 0.021) but not in cohort studies (OR: 0.83; 95% CI: 0.67-1.02; P = 0.071). High or intermediate coffee intake might have protective effects against oral cavity cancer. However, the underlying mechanisms must be further evaluated in large-scale prospective cohort studies.

Coffee and tea drinking and risk of cancer of the urinary tract in male smokers

PURPOSE

We evaluated the association of coffee and tea drinking with risk of the urinary tract cancer in Finnish men, with high coffee consumption, using data from the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study.

METHODS

The ATBC trial conducted from 1985 to 1993 enrolled 29,133 male smokers. We used Cox proportional hazards regression models to estimate hazard ratios (HRs) and confidence intervals (CIs), using men who drank more than 0 but less than 1 cup coffee/d and tea nondrinkers as our referent group for coffee and tea analyses, respectively.

RESULTS

During 472,402 person-years of follow-up, 835 incident cases of bladder cancer and 366 cases of renal cell carcinoma were ascertained. For bladder cancer, we observed no association for coffee consumption (HR ≥4 vs. >0 to <1 cups/d = 1.16, 95% CI = 0.86-1.56) and a borderline statistically significant inverse association for tea consumption (HR ≥1 vs. 0 cup/d = 0.77, 95% CI = 0.58-1.00). For renal cell carcinoma, we observed no association for coffee (HR ≥4 vs. >0 to <1 cups/d = 0.85, 95% CI = 0.55-1.32) or tea consumption (HR ≥1 vs. 0 cup/d = 1.00, 95% CI = 0.68-1.46). We found no impact of coffee preparation on coffee-cancer associations.

CONCLUSIONS

Coffee drinking was not associated with urinary tract cancers risk. Further research on tea and bladder cancer is warranted.

Association between tea and coffee consumption and brain cancer risk: an updated meta-analysis

Background

Previous studies had demonstrated some associations between coffee and tea consumption and brain cancer risk resulted in an inconsistent relationship. We therefore performed this study to further explore the association between them.

Method

By searching PubMed, Embase, and Web of Science, we retrieved up to 1 November 2018, 11 relevant literature of publications were collected by 2 people eventually. Stata 14.0 software was used for data analysis.

Results

In total, 11 articles (11 articles for coffee, 8 articles for tea, and 4 articles for coffee plus tea) were used in this meta-analysis. A statistically significant protective effect of coffee consumption and brain cancer risk was found (RR = 0.785, 95% CI = 0.580–0.984, I² = 65.6%, P_{for heterogeneity} = 0.001), especially in Asian populations (RR = 0.217, 95% CI = 0.042–0.896). However, the association between the risk of brain cancer and tea consumption was non-significant in the whole result (RR = 0.897, 95% CI = 0.739–1.088, I² = 29.9%, P_{for heterogeneity} = 0.189), but significant in American populations (RR = 0.798, 95% CI = 0.646–0.986). Interestingly, the RR was 0.684 (95% CI = 0.481–0.975) for the risk of brain cancer when compared the highest versus the lowest category consumption of coffee plus tea.

Conclusion

Findings from this study suggested that higher consumption of coffee may contribute to the lower development of brain cancer in Asian populations. Tea consumption had an inverse association for the risk of brain cancer in American populations, instead of other populations.

Electronic supplementary material

The online version of this article (10.1186/s12957-019-1591-y) contains supplementary material, which is available to authorized users.

Protective effects of coffee consumption following liver transplantation for hepatocellular carcinoma in cirrhosis

BACKGROUND

Increasing evidence suggests that coffee consumption might protect against hepatocellular carcinoma (HCC) and liver cirrhosis-associated death risk. Caffeine is a natural antagonist to extracellular adenosine and exhibits experimental tumoricidal activity.

AIM

To evaluate if coffee consumption has beneficial effects on HCC recurrence after orthotopic liver transplantation (OLT).

METHODS

Coffee consumption of patients before and after OLT for HCC was assessed and correlated with HCC recurrence. HepG2 cells were analysed for proliferation and metastasis potential after treatment with adenosine, in the presence or absence of adenosine receptor antagonists. Expression of adenosine receptors was determined, and known adenosine-mediated cancer pathways inclusive of MAPK and NF-kappa B were tested.

RESULTS

Ninety patients underwent OLT for HCC. Sixteen (17.8%) patients experienced HCC recurrence after median time of 11.5 months (range 1-40.5). For overall survival postoperative coffee intake emerged as major factor of hazard reduction in a multivariate analysis (HR = 0.2936, 95% CI = 0.12-0.71, P = 0.006). Those with such postoperative coffee intake (≥3 cups per day) had a longer overall survival than those who consumed less or no coffee: M = 11.0 years, SD = 0.52 years vs. M = 7.48 years, SD = 0.76 years = 4.7, P = 0.029).

CONCLUSIONS

Coffee consumption is associated with a decreased risk of HCC recurrence and provides for increased survival following OLT. We suggest that these results might be, at least in part, associated with the antagonist activity of caffeine on adenosine-A2AR mediated growth-promoting effects on HCC cells.

Potential nutraceutical and food additive properties and risks of coffee: a comprehensive overview

Coffee is a composite mixture of more than a thousand diverse phytochemicals like alkaloids, phenolic compounds, vitamins, carbohydrates, lipids, minerals and nitrogenous compounds. Coffee has multifunctional properties as a food additive and nutraceutical. As a nutraceutical, coffee has anti-inflammatory, anti-oxidant, antidyslipidemic, anti-obesity, type-2 diabetes mellitus (DM), and cardiovascular diseases (CVD), which can serve for the treatment and prevention of metabolic syndrome and associated disorders. On the other hand, as a food additive, coffee has antimicrobial activity against a wide range of microorganisms, inhibits lipid peroxidation (LPO), and can function as a prebiotic. The outcomes of different studies also revealed that coffee intake may reduce the incidence of numerous chronic diseases, like liver disease, mental health, and it also overcomes the all-cause mortality, and suicidal risks. In some studies, high intake of coffee is linked to increase CVD risk factors, like cholesterol, plasma homocysteine and blood pressure (BP). There is also a little evidence that associated the coffee consumption with increased risk of lung tumors in smokers. Among adults who consume the moderate amount of coffee, there is slight indication of health hazards with strong indicators of health benefits. Moreover, existing literature suggests that it may be cautious for pregnant women to eliminate the chances of miscarriages and impaired fetal growth. The primary purpose of this narrative review is to provide an overview of the findings of the positive impacts and risks of coffee consumption on human health. In conclusion, to date, the best available evidence from research indicates that drinking coffee up to 3-4 cups/day provides health benefits for most people.

Reduction of βN-alkanoyl-5-hydroxytryptamides and diterpenes by yeast supplementation to green coffee during wet processing

Coffee is one of the most consumed non-alcoholic beverages in the world. It is well known that some compounds present in coffee beans have important biological activities. In this study, evidence was turned to ^βN-alkanoyl-5-hydroxytryptamides (C-5HTs) and to the furokaurane diterpenes cafestol and kahweol, associated with gastric irritation and increasing of blood cholesterol, respectively. Fermentation in coffee post-harvest wet process was induced by three Saccharomyces cerevisiae yeasts (for bakery, white and sparkling wines) as starter cultures. Variations in mass, time, temperature and pH (56 experiments under fractional factorial and mixture experimental designs) were tested. Substantial reductions for C-5HTs (up to 38% reduction for C20-5HT and 26% for C22-5HT) as well as for diterpenes (54% for cafestol and 53% for kahweol) were obtained after treating green coffee beans with 0.6 g of a 1:1:1 mixture the three yeasts for 12 h at 15 °C and pH 4. Caffeine and 5-CQA content, monitored in the green coffee beans, did not change. Therefore, the use of starter cultures during coffee post-harvest wet process has influence on the amount of some important compounds related to health and improves the sensory quality of the beverage.

In vivo protein expression changes in mouse livers treated with dialyzed coffee extract as determined by IP-HPLC

Background

Coffee extract has been investigated by many authors, and many minor components of coffee are known, such as polyphenols, diterpenes (kahweol and cafestol), melanoidins, and trigonelline, to have anti-inflammatory, anti-oxidant, anti-angiogenic, anticancer, chemoprotective, and hepatoprotective effects. Therefore, it is necessary to know its pharmacological effect on hepatocytes which show the most active cellular regeneration in body.

Methods

In order to determine whether coffee extract has a beneficial effect on the liver, 20 C57BL/6J mice were intraperitoneally injected once with dialyzed coffee extract (DCE)-2.5 (equivalent to 2.5 cups of coffee a day in man), DCE-5, or DCE-10, or normal saline (control), and then followed by histological observation and IP-HPLC (immunoprecipitation high performance liquid chromatography) over 24 h.

Results

Mice treated with DCE-2.5 or DCE-5 showed markedly hypertrophic hepatocytes with eosinophilic cytoplasms, while those treated with DCE-10 showed slightly hypertrophic hepatocytes, which were well aligned in hepatic cords with increased sinusoidal spaces. DCE induced the upregulations of cellular proliferation, growth factor/RAS signaling, cellular protection, p53-mediated apoptosis, angiogenesis, and antioxidant and protection-related proteins, and the downregulations of NFkB signaling proteins, inflammatory proteins, and oncogenic proteins in mouse livers. These protein expression changes induced by DCE were usually limited to the range ± 10%, suggesting murine hepatocytes were safely reactive to DCE within the threshold of physiological homeostasis. DCE-2.5 and DCE-5 induced relatively mild dose-dependent changes in protein expressions for cellular regeneration and de novo angiogenesis as compared with non-treated controls, whereas DCE-10 induced fluctuations in protein expressions.

Conclusion

These observations suggested that DCE-2.5 and DCE-5 were safer and more beneficial to murine hepatocytes than DCE-10. It was also found that murine hepatocytes treated with DCE showed mild p53-mediated apoptosis, followed by cellular proliferation and growth devoid of fibrosis signaling (as determined by IP-HPLC), and subsequently progressed to rapid cellular regeneration and wound healing in the absence of any inflammatory reaction based on histologic observations.

Electronic supplementary material

The online version of this article (10.1186/s40902-018-0183-z) contains supplementary material, which is available to authorized users.

The Impact of Coffee and Its Selected Bioactive Compounds on the Development and Progression of Colorectal Cancer In Vivo and In Vitro

Coffee is one of the most popular beverages worldwide. Coffee contains bioactive compounds that affect the human body such as caffeine, caffeic acid, chlorogenic acids, trigonelline, diterpenes, and melanoidins. Some of them have demonstrated potential anticarcinogenic effects in animal models and in human cell cultures, and may play a protective role against colorectal cancer. Colorectal cancer (CRC) is the third leading cause of cancer-related mortality in the USA and other countries. Dietary patterns, as well as the consumption of beverages, may reduce the risk of CRC incidence. In this review, we focus on published epidemiological studies concerning the association of coffee consumption and the risk of development of colorectal cancer, and provide a description of selected biologically active compounds in coffee that have been investigated as potential cancer-combating compounds: Caffeine, caffeic acid (CA), chlorogenic acids (CGAs), and kahweol in relation to colorectal cancer progression in in vitro settings. We review the impact of these substances on proliferation, viability, invasiveness, and metastasis, as well as on susceptibility to chemo- and radiotherapy of colorectal cancer cell lines cultured in vitro.

In vitro protein expression changes in RAW 264.7 cells and HUVECs treated with dialyzed coffee extract by immunoprecipitation high performance liquid chromatography

RAW 264.7 cells and HUVECs were compared to evaluate the effects of dialyzed coffee extract (DCE) and artificial coffee (AC). Immunoprecipitation high performance liquid chromatography (IP-HPLC) showed DCE-2.5- (equivalent to 2.5 cups of coffee a day) and DCE-5-induced protein expression that was beneficial to human health, i.e., they led to significant increases in proliferation-, immunity-, cellular protection-, antioxidant signaling-, and osteogenesis-related proteins but decreases in inflammation-, NFkB signaling-, cellular apoptosis-, and oncogenic signaling-related proteins in RAW 264.7 cells, and slight decreases in angiogenesis-related proteins in HUVECs. These protein expression changes were less frequently observed for DCE-10 treatment, while AC treatment induced very different changes in protein expression. We suggest that the favorable cellular effects of DCE were derived from minor coffee elements that were absent in AC, and that the reduced effects of DCE-10 compared with those of DCE-2.5 or DCE-5 might have been caused by greater adverse reactions to caffeine and chlorogenic acid in DCE-10 than DCE-2.5 or DCE-5. IP-HPLC results suggested that minor coffee elements in DCE might play beneficial roles in the global protein expression of proliferation-, immunity-, anti-inflammation-, cell protection-, antioxidant-, anti-apoptosis-, anti-oncogenesis-, and osteogenesis-related proteins in RAW 264.7 cells and enhance anti-angiogenic signaling in HUVECs.

Ent-kaurane diterpenoids from the cherries of Coffea arabica

Four new rearranged ent-kaurane diterpenoids named as caffruenol A (1), caffruenol B (2), caffruolide A (3), caffruolide B (4), along with eleven known analogues (5-15) were isolated from the cherries of Coffea arabica. The structures of new compounds were elucidated by extensive spectroscopic analysis and X-ray crystallography. Coffruenols A and B (1 and 2) possessed an ent-4(18)-kaurene framework and might play an important role on the biosynthesis of the rearranged diterpenes that occurred in C. arabica. Moreover, inhibitory effects of compounds 1-4 on nitric oxide (NO) production in lipopolysaccharide-activited RAW 264.7 macrophages were evaluated.

Coffee drinking and colorectal cancer and its subsites: A pooled analysis of 8 cohort studies in Japan

Coffee is a rich source of bioactive compounds that have potential anticarcinogenic effects. However, it remains unclear whether coffee drinking is associated with colorectal cancer. Also, despite different etiological factors involved in gut physiology, few studies have investigated this association by anatomical site of the lesion. To address these issues, this study examined the association between coffee drinking and colorectal cancer in a pooled analysis from 8 cohort studies conducted in Japan. Among 320,322 participants followed up for 4,503,274 person-years, 6,711 incident colorectal cancer cases were identified. Study-specific hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazards models and then pooled using the random effects model. Coffee drinking was not materially associated with colorectal cancer risk in men or women (pooled HR 0.92, 95% CI 0.82-1.03 in men and pooled HR 0.90, 95% CI 0.76-1.07 in women). Analysis by subsite showed a lower risk of colon cancer among female drinkers of ≥3 cups coffee/day (pooled HR 0.80, 95% CI 0.64-0.99). There was no such association in men. Coffee drinking was not associated with risk of rectal cancer in men or women. Results were virtually the same among never smokers except for an increased risk of rectal cancer associated with frequent coffee consumption. Coffee drinking may be associated with lower risk of colon cancer in Japanese women.

Coffee and Tea Consumption and the Contribution of Their Added Ingredients to Total Energy and Nutrient Intakes in 10 European Countries: Benchmark Data from the Late 1990s

BACKGROUND

Coffee and tea are among the most commonly consumed nonalcoholic beverages worldwide, but methodological differences in assessing intake often hamper comparisons across populations. We aimed to (i) describe coffee and tea intakes and (ii) assess their contribution to intakes of selected nutrients in adults across 10 European countries.

METHOD

Between 1995 and 2000, a standardized 24-h dietary recall was conducted among 36,018 men and women from 27 European Prospective Investigation into Cancer and Nutrition (EPIC) study centres. Adjusted arithmetic means of intakes were estimated in grams (=volume) per day by sex and centre. Means of intake across centres were compared by sociodemographic characteristics and lifestyle factors.

RESULTS

In women, the mean daily intake of coffee ranged from 94 g/day (~0.6 cups) in Greece to 781 g/day (~4.4 cups) in Aarhus (Denmark), and tea from 14 g/day (~0.1 cups) in Navarra (Spain) to 788 g/day (~4.3 cups) in the UK general population. Similar geographical patterns for mean daily intakes of both coffee and tea were observed in men. Current smokers as compared with those who reported never smoking tended to drink on average up to 500 g/day more coffee and tea combined, but with substantial variation across centres. Other individuals' characteristics such as educational attainment or age were less predictive. In all centres, coffee and tea contributed to less than 10% of the energy intake. The greatest contribution to total sugar intakes was observed in Southern European centres (up to ~20%).

CONCLUSION

Coffee and tea intake and their contribution to energy and sugar intake differed greatly among European adults. Variation in consumption was mostly driven by geographical region.

Coffee and cancer risk: a summary overview

We reviewed available evidence on coffee drinking and the risk of all cancers and selected cancers updated to May 2016. Coffee consumption is not associated with overall cancer risk. A meta-analysis reported a pooled relative risk (RR) for an increment of 1 cup of coffee/day of 1.00 [95% confidence interval (CI): 0.99-1.01] for all cancers. Coffee drinking is associated with a reduced risk of liver cancer. A meta-analysis of cohort studies found an RR for an increment of consumption of 1 cup/day of 0.85 (95% CI: 0.81-0.90) for liver cancer and a favorable effect on liver enzymes and cirrhosis. Another meta-analysis showed an inverse relation for endometrial cancer risk, with an RR of 0.92 (95% CI: 0.88-0.96) for an increment of 1 cup/day. A possible decreased risk was found in some studies for oral/pharyngeal cancer and for advanced prostate cancer. Although data are mixed, overall, there seems to be some favorable effect of coffee drinking on colorectal cancer in case-control studies, in the absence of a consistent relation in cohort studies. For bladder cancer, the results are not consistent; however, any possible direct association is not dose and duration related, and might depend on a residual confounding effect of smoking. A few studies suggest an increased risk of childhood leukemia after maternal coffee drinking during pregnancy, but data are limited and inconsistent. Although the results of studies are mixed, the overall evidence suggests no association of coffee intake with cancers of the stomach, pancreas, lung, breast, ovary, and prostate overall. Data are limited, with RR close to unity for other neoplasms, including those of the esophagus, small intestine, gallbladder and biliary tract, skin, kidney, brain, thyroid, as well as for soft tissue sarcoma and lymphohematopoietic cancer.

Coffee consumption is not associated with ovarian cancer risk: a dose-response meta-analysis of prospective cohort studies

Background

Coffee consumption has been associated with numerous cancers, but evidence on ovarian cancer risk is controversial. Therefore, we performed a meta-analysis on prospective cohort studies in order to review the evidence on coffee consumption and risk of ovarian cancer.

Methods

Studies were identified through searching the PubMed and MEDLINE databases up to March 2017. Risk estimates were retrieved from the studies, and dose-response analysis was modelled by using restricted cubic splines. Additionally, a stratified analysis by menopausal status was performed.

Results

A total of 8 studies were eligible for the dose-response meta-analysis. Studies included in the analysis comprised 787,076 participants and 3,541 ovarian cancer cases. The results showed that coffee intake was not associated with ovarian cancer risk (RR = 1.06, 95% CI: 0.89, 1.26). Stratified and subgroup analysis showed consisted results.

Conclusions

This comprehensive meta-analysis did not find evidence of an association between the consumption of coffee and risk of ovarian cancer.

Coffee consumption and risk of esophageal cancer incidence: A meta-analysis of epidemiologic studies

BACKGROUND

In epidemiologic studies, association between coffee consumption and esophageal cancer risk is inconsistent.

OBJECTIVE

The aim of tjis study was to evaluate the effect of coffee on esophageal cancer by combining several similar studies.

METHODS

We conducted a meta-analysis for association of coffee intake and esophageal cancer incidence. Eleven studies, including 457,010 participants and 2628 incident cases, were identified. A relative risk (RR, for cohort study) or odds ratio (OR, for case-control study) of heavy coffee drinkers was calculated, compared with light coffee drinkers or non-drinkers. The analysis was also stratified by cancer types (esophageal squamous cell carcinoma and esophageal adenocarcinoma), sex, and geographic region.

RESULTS

The summarized OR of having esophageal cancer in heavy coffee drinkers was 0.93 (95% confidence interval [CI]: 0.73-1.12), compared with light coffee drinkers. When stratified by sex, pathologic type of esophageal cancer, and type of epidemiologic study, we did not find any association of coffee consumption and esophageal cancer incidence. However, an inverse association between coffee consumption and incidence of esophageal cancer was found in East Asia participants with OR of 0.64 (95% CI: 0.44-0.83), but not in Euro-America participants (OR = 1.05; 95% CI: 0.81-1.29).

CONCLUSION

There is a protective role of coffee consumption against esophageal cancer in East Asians, but not in Euro-Americans.

Association Between Coffee Intake After Diagnosis of Colorectal Cancer and Reduced Mortality

BACKGROUND & AIMS

Few studies have examined the association between coffee intake and survival after diagnosis of colorectal cancer (CRC). We performed a prospective study to investigate the association between coffee intake after a diagnosis of CRC and mortality.

METHODS

We collected data from the Nurses' Health Study (1984-2012) and Health Professionals Follow-up Study (1986-2012), following 1599 patients diagnosed with stage 1, 2, or 3 CRC. CRC was reported on questionnaires and ascertained by review of medical records and pathology reports; intake of food and beverages was determined from responses to semi-quantitative food frequency questionnaires. Participants were asked how often during the previous year that they consumed coffee, with 1 cup as the standard portion size. The first questionnaire response collected at least 6 months but not more than 4 years after diagnosis was used for assessment of post-diagnostic intake (median time from diagnosis to the dietary assessment, 2.2 years). The last semi-quantitative food frequency questionnaire prior to diagnosis was used to assess pre-diagnostic dietary intake.

RESULTS

During a median of 7.8 years of follow-up, we documented 803 deaths, of which 188 were because of CRC. In the multivariable adjusted models, compared with nondrinkers, patients who consumed at least 4 cups of coffee per day had a 52% lower risk of CRC-specific death (hazard ratio [HR] 0.48; 95% CI, 0.28-0.83; P for trend=.003) and 30% reduced risk of all-cause death (HR, 0.70; 95% CI, 0.54-0.91; P for trend <.001). High intake of caffeinated and decaffeinated coffee (2 or more cups/day) was associated with lower risk of CRC-specific mortality and all-cause mortality. When coffee intake before vs after CRC diagnosis were examined, compared with patients consistently consuming low amounts (less than 2 cups/day), those who maintained a high intake (2 or more cups/day) had a significantly lower risk of CRC-specific death (multivariable HR, 0.63; 95% CI, 0.44-0.89) and death from any cause (multivariable HR, 0.71; 95% CI, 0.60-0.85).

CONCLUSIONS

In an analysis data from the Nurses' Health Study and Health Professionals Follow-up Study, we associated intake of caffeinated and decaffeinated coffee after diagnosis of CRC with lower risk of CRC-specific death and overall death. Studies are needed to determine the mechanisms by which coffee might reduce CRC progression.

Coffee consumption and health: umbrella review of meta-analyses of multiple health outcomes

Objectives To evaluate the existing evidence for associations between coffee consumption and multiple health outcomes.Design Umbrella review of the evidence across meta-analyses of observational and interventional studies of coffee consumption and any health outcome.Data sources PubMed, Embase, CINAHL, Cochrane Database of Systematic Reviews, and screening of references.Eligibility criteria for selecting studies Meta-analyses of both observational and interventional studies that examined the associations between coffee consumption and any health outcome in any adult population in all countries and all settings. Studies of genetic polymorphisms for coffee metabolism were excluded.Results The umbrella review identified 201 meta-analyses of observational research with 67 unique health outcomes and 17 meta-analyses of interventional research with nine unique outcomes. Coffee consumption was more often associated with benefit than harm for a range of health outcomes across exposures including high versus low, any versus none, and one extra cup a day. There was evidence of a non-linear association between consumption and some outcomes, with summary estimates indicating largest relative risk reduction at intakes of three to four cups a day versus none, including all cause mortality (relative risk 0.83 (95% confidence interval 0.79 to 0.88), cardiovascular mortality (0.81, 0.72 to 0.90), and cardiovascular disease (0.85, 0.80 to 0.90). High versus low consumption was associated with an 18% lower risk of incident cancer (0.82, 0.74 to 0.89). Consumption was also associated with a lower risk of several specific cancers and neurological, metabolic, and liver conditions. Harmful associations were largely nullified by adequate adjustment for smoking, except in pregnancy, where high versus low/no consumption was associated with low birth weight (odds ratio 1.31, 95% confidence interval 1.03 to 1.67), preterm birth in the first (1.22, 1.00 to 1.49) and second (1.12, 1.02 to 1.22) trimester, and pregnancy loss (1.46, 1.06 to 1.99). There was also an association between coffee drinking and risk of fracture in women but not in men.Conclusion Coffee consumption seems generally safe within usual levels of intake, with summary estimates indicating largest risk reduction for various health outcomes at three to four cups a day, and more likely to benefit health than harm. Robust randomised controlled trials are needed to understand whether the observed associations are causal. Importantly, outside of pregnancy, existing evidence suggests that coffee could be tested as an intervention without significant risk of causing harm. Women at increased risk of fracture should possibly be excluded.

Coffee and green tea consumption and subsequent risk of acute myeloid leukemia and myelodysplastic syndromes in Japan

Although coffee and green tea are suggested to reduce the risk of some types of cancers, only a few epidemiological studies have investigated their effect on the risk of acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS). Here, we investigated the association of coffee and green tea consumption and the risk of AML and MDS in a large-scale population-based cohort study in Japan. A total of 95,807 Japanese subjects (45,937 men and 49,870 women; age 40-69 years at baseline) were followed to the end of 2012, for an average of 18 years. Hazard ratios (HRs) and 95% confidence intervals (95% CIs) for the association between coffee and green tea consumption at baseline and the risk of AML and MDS were assessed using a Cox proportional hazards model with adjustment for potential confounders. During 1,751.956 person-years, we identified 85 AML cases and 70 MDS cases. Our findings showed no significant association between coffee consumption and the risk of AML, or between green tea consumption and the risk of AML or MDS. In contrast, we observed a decreasing dose-response relationship between coffee consumption and the risk of MDS among men (almost none: reference, 1-4 times/week: HR = 0.83, 95% CI: 0.43-1.62; ≥1cups/day: HR = 0.47, 0.22-0.99, p for trend = 0.049). Stratified analysis by smoking status suggested that the observed relative risk for AML and MDS of coffee drinkers relative to non-coffee drinkers might be due to residual confounding by smoking. These findings deserve further investigation in future studies.

Association of coffee consumption with risk of colorectal cancer: a meta-analysis of prospective cohort studies

A meta-analysis was performed to assess the association of coffee consumption with colorectal cancer and to investigate the shape of the association. Relevant prospective cohort studies were identified by a comprehensive search of the PubMed, Embase and Web of Science databases from their inception through August 2015. Either a random-effects model or fixed-effects model was used to compute the pooled risk estimates when appropriate. Linear and nonlinear dose-response meta-analyses were also performed. Nineteen prospective cohort studies involving 2,046,575 participants and 22,629 patients with colorectal cancer were included. The risk of colon cancer was decreased by 7% for every 4 cups per day of coffee (RR=0.93, 95%CI, 0.88-0.99; P=0.199). There was a threshold approximately five cups of coffee per day, and the inverse association for colorectal cancer appeared to be stronger at a higher range of intake. However, a nonlinear association of rectal cancer with coffee consumption was not observed (P for nonlinearity = 0.214). In conclusion, coffee consumption is significantly associated with a decreased risk of colorectal cancer at ≥ 5 cups per day of coffee consumption. The findings support the recommendations of including coffee as a healthy beverage for the prevention of colorectal cancer.

Association between coffee or tea drinking and Barrett's esophagus or esophagitis: an Italian study

BACKGROUND/OBJECTIVES

Only a few papers have treated of the relationship between Barrett's esophagus (BE) or erosive esophagitis (E) and coffee or tea intake. We evaluated the role of these beverages in BE and E occurrence.

SUBJECTS/METHODS

Patients with BE (339), E (462) and controls (619) were recruited. Data on coffee and tea and other individual characteristics were collected using a structured questionnaire.

RESULTS

BE risk was higher in former coffee drinkers, irrespective of levels of exposure (cup per day; ⩽1: OR=3.76, 95% CI 1.33-10.6; >1: OR=3.79, 95% CI 1.31-11.0; test for linear trend (TLT) P=0.006) and was higher with duration (>30 years: OR=4.18, 95% CI 1.43-12.3; TLT P=0.004) and for late quitters, respectively (⩽3 years from cessation: OR=5.95, 95% CI 2.19-16.2; TLT P<0.001). The risk of BE was also higher in subjects who started drinking coffee later (age >18 years: OR=6.10, 95% CI 2.15-17.3). No association was found in current drinkers, but for an increased risk of E in light drinkers (<1 cup per day OR =1.85, 95% CI 1.00-3.43).A discernible risk reduction of E (about 20%, not significant) and BE (about 30%, P<0.05) was observed in tea drinkers.

CONCLUSIONS

Our data were suggestive of a reduced risk of BE and E with tea intake. An adverse effect of coffee was found among BE patients who had stopped drinking coffee. Coffee or tea intakes could be indicative of other lifestyle habits with protective or adverse impact on esophageal mucosa.

The role of Nrf2-Keap1 axis in colorectal cancer, progression, and chemoresistance

Colorectal cancer is the third common cancer after lung and genital cancers worldwide with more than 1.2 million new cases diagnosed annually. Although extensive progress has been made in the treatment of colorectal cancer, finding novel targets for early diagnosis and effective treatment of these patients is an urgent need. Nuclear factor-erythroid 2-kelch-like ECH-associated protein 1 signaling pathway plays a key role in protecting cells from the damage of intracellular oxidative stress and extracellular oxidizing agents. Nuclear factor-erythroid 2 is a transcription factor that creates intracellular redox homeostasis via transcriptional activity and interaction with kelch-like ECH-associated protein 1. Furthermore, it contributes to survival and chemoresistance of colorectal cancer cells which is mediated by overexpression of cytoprotective and multidrug resistance genes. In this review, the dual role of nuclear factor-erythroid 2 signaling in induction of colorectal cancer cell survival and death as well as the possibility of targeting nuclear factor-erythroid 2-kelch-like ECH-associated protein 1 axis as an advanced strategy in prevention and effective treatment of colorectal cancer patients have been discussed.

Protective effects of coffee against oxidative stress induced by the tobacco carcinogen benzo[α]pyrene

AIMS

Coffee consumption has been epidemiologically associated with a lower risk for liver cirrhosis and cancer. UDP-glucuronosyltransferases (UGT1A) catalyze the detoxification of reactive metabolites thereby acting as indirect antioxidants. Aim of the study was to examine UGT1A regulation in response to Benzo[α]pyrene (BaP) to elucidate the potentially protective effects of coffee on BaP-induced oxidative stress and toxicity.

RESULTS

In cell culture (HepG2, KYSE70 cells) and in htgUGT1A-WT mice, UGT1A transcription was activated by BaP, while it was reduced or absent htgUGT1A-SNP (containing 10 commonly occurring UGT1A-SNPs) mice. siRNA-mediated knockdown identified aryl hydrocarbon receptor (AhR) and nuclear factor erythroid2-related factor-2 (Nrf2) as mediators of BaP-induced UGT1A upregulation. Exposure to coffee led to a reduction of BaP-induced production of reactive oxygen species in vitro and in htgUGT1A-WT and -SNP mice. After UGT1A silencing by UGT1A-specific siRNA in cell culture, the coffee-mediated reduction of ROS production was significantly impaired compared to UGT1A expressing cells.

CONCLUSION

A common UGT1A haplotype, prevalent in 9% (homozygous) of the White population, significantly impairs the expression of UGT1A enzymes in response to the putative tobacco carcinogen BaP and is likely to represent a significant risk factor for reduced detoxification and increased genotoxicity. Coffee was demonstrated to inhibit BaP-induced production of oxidative stress by UGT1A activation, and is therefore an attractive candidate for chemoprotection in risk groups for HCC or other tumors.

Asia-Pacific clinical practice guidelines on the management of hepatocellular carcinoma: a 2017 update

There is great geographical variation in the distribution of hepatocellular carcinoma (HCC), with the majority of all cases worldwide found in the Asia-Pacific region, where HCC is one of the leading public health problems. Since the "Toward Revision of the Asian Pacific Association for the Study of the Liver (APASL) HCC Guidelines" meeting held at the 25th annual conference of the APASL in Tokyo, the newest guidelines for the treatment of HCC published by the APASL has been discussed. This latest guidelines recommend evidence-based management of HCC and are considered suitable for universal use in the Asia-Pacific region, which has a diversity of medical environments.

Healthy dietary patterns decrease the risk of colorectal cancer in the Mecca Region, Saudi Arabia: a case-control study

Background

Colorectal cancer (CRC) is the first most common cancer in males and the third most common cancer in females in Saudi Arabia. Dietary habits are strongly associated with the inhibition or proliferation of malignancy. Therefore, this study is aiming to investigate the risks and protective benefits of dietary factors affecting CRC in the Mecca region of Saudi Arabia.

Methods

A case-control study was conducted from June 2014 to March 2015. One hundred thirty-seven patients with colon and/or rectal cancer were recruited in the case group, while 164 healthy participants were recruited in the control group. A questionnaire was completed with the help of trained dietitians to study the effects of several dietary patterns on the risk of CRC.

Results

Dairy product intake of 1–5 servings/day, legume intake of 3–5 servings/week, leafy vegetables intake of 1–5 servings/week, olive oil intake of 1–5 servings/week, black tea intake of three or more cups/day, and coffee intake of one or more cups/day was found to decrease the risk of CRC in participants.

Conclusion

This study highlights the importance of changing dietary habits to decrease CRC incidence in the Mecca region.

Cafestol, a diterpene molecule found in coffee, induces leukemia cell death

To evaluate the antitumor properties of Cafestol four leukemia cell lines were used (NB4, K562, HL60 and KG1). Cafestol exhibited the highest cytotoxicity against HL60 and KG1 cells, as evidenced by the accumulation of cells in the sub-G1 fraction, mitochondrial membrane potential reduction, accumulation of cleaved caspase-3 and phosphatidylserine externalization. An increase in CD11b and CD15 differentiation markers with attenuated ROS generation was also observed in Cafestol-treated HL60 cells. These results were similar to those obtained following exposure of the same cell line to cytarabine (Ara-C), an antileukemic drug. Cafestol and Ara-C reduced the clonogenic potential of HL60 cells by 100%, but Cafestol spared murine colony forming unit- granulocyte/macrophage (CFU-GM), which retained their clonogenicity. The co-treatment of Cafestol and Ara-C reduced HL60 cell viability compared with both drugs administered alone. In conclusion, despite the distinct molecular mechanisms involved in the activity of Cafestol and Ara-C, a similar cytotoxicity towards leukemia cells was observed, which suggests a need for prophylactic-therapeutic pre-clinical studies regarding the anticancer properties of Cafestol.

Coffee, including caffeinated and decaffeinated coffee, and the risk of hepatocellular carcinoma: a systematic review and dose-response meta-analysis

OBJECTIVES

To examine the association between coffee, including caffeinated and decaffeinated coffee, with hepatocellular carcinoma (HCC) and assess the influence of HCC aetiology and pre-existing liver disease.

DESIGN

We performed a systematic review and meta-analysis. We calculated relative risks (RRs) of HCC according to caffeinated and decaffeinated coffee consumption using a random-effects dose-response meta-analysis. We tested for modification of the effect estimate by HCC aetiology and pre-existing liver disease. We judged the quality of evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) criteria.

RESULTS

We found 18 cohorts, involving 2 272 642 participants and 2905 cases, and 8 case-control studies, involving 1825 cases and 4652 controls. An extra two cups per day of coffee was associated with a 35% reduction in the risk of HCC (RR 0.65, 95% CI 0.59 to 0.72). The inverse association was weaker for cohorts (RR 0.71, 95% CI 0.65 to 0.77), which were generally of higher quality than case-control studies (RR 0.53, 95% CI 0.41 to 0.69). There was evidence that the association was not significantly altered by stage of liver disease or the presence/absence of high alcohol consumption, high body mass index, type 2 diabetes mellitus, smoking, or hepatitis B and C viruses. An extra two cups of caffeinated and decaffeinated coffee (2 and 3 cohort studies, respectively) were associated with reductions of 27% (RR 0.73, 95% CI 0.63 to 0.85) and 14% (RR 0.86, 95% CI 0.74 to 1.00) in the risk of HCC. However, due to a lack of randomised controlled trials, potential publication bias and there being no accepted definition of coffee, the quality of evidence under the GRADE criteria was 'very low'.

CONCLUSIONS

Increased consumption of caffeinated coffee and, to a lesser extent, decaffeinated coffee are associated with reduced risk of HCC, including in pre-existing liver disease. These findings are important given the increasing incidence of HCC globally and its poor prognosis.

Coffee consumption and the risk of colorectal cancer by anatomical subsite in Japan: Results from the HERPACC studies

Consumption of coffee, a popular beverage worldwide, has been associated with lower colorectal cancer (CRC) risk. Although CRC exhibits different biological characteristics by anatomical subsite, the possibly heterogeneous impact of coffee on CRC by anatomical subsite has remained unclear. Here, we conducted two case-control studies to examine the association between coffee consumption and CRC risk as well as risk by anatomic subsite among Japanese using data from the Hospital-based Epidemiological Research Program at Aichi Cancer Center I and II (HERPACC-I and II). Subjects were enrolled in HERPACC-I between 1988 and 2000 and in HERPACC-II between 2001 and 2005. Coffee consumption was measured with a self-administered questionnaire. A conditional logistic regression model was used to calculate odds ratios (ORs) of CRC with coffee consumption, adjusted for potential confounders of age, smoking, alcohol drinking, red meat intake, BMI, exercise, family history of CRC, and diabetes mellitus history. We estimated summary ORs by pooling study-specific ORs with a fixed effects model. In total, 2,696 CRC cases and 13,480 non-cancer outpatients as controls were included. Overall, compared to non-drinkers, ORs of less than 1 cup/day, 1-2 cups/day and 3 or more cups/day for CRC were 0.88 (95% CI: 0.77-1.00), 0.90 (95% CI: 0.80-1.01) and 0.78 (95% CI: 0.65-0.92), respectively (trend-p = 0.009). Subsite-specific analysis revealed a significant inverse linear trend between coffee consumption and distal colon cancer (p-trend = 0.048), and a tendency toward a lower risk of rectal cancer (p-trend = 0.068). These findings suggest that coffee consumption might impact the prevention of CRC, especially distal colon cancer.