Coffee consumption and risk of renal cancer: a meta-analysis of cohort evidence

Coffee consumption, cancer, and healthy aging: epidemiological evidence and underlying mechanisms

This comprehensive review examines the role of coffee consumption in promoting healthy aging and its potential impact on cancer prevention. Previous research has shown that moderate coffee intake may contribute to extending healthspan and enhancing longevity through beneficial effects on cardiometabolic health and key biological processes involved in aging. However, the relationship between coffee consumption and cancer risk remains controversial. This review synthesizes longitudinal observational and interventional data on the effects of coffee consumption on overall and site-specific cancers, explores underlying biological mechanisms, and discusses clinical and public health implications. Additionally, the review highlights evidence from Mendelian randomization (MR) studies to assess potential causal relationships. Our findings suggest that coffee consumption is associated with a reduced risk of several cancers, including skin, liver, prostate, and endometrial cancers, and may also lower cancer recurrence rates, particularly in colorectal cancer. These protective associations appear consistent across different demographic groups, with the most significant benefits observed at consumption levels of three or more cups per day. However, evidence is inconclusive for many other cancers, and coffee consumption is consistently linked to an increased risk of lung cancer. MR studies generally do not support a strong causal relationship for most cancers, though some suggest potential protective effects for hepatocellular, colorectal, and possibly prostate cancers, with mixed results for ovarian cancer and an increased risk for esophageal cancer and multiple myeloma. The protective effect of coffee on liver and prostate cancer is supported by both observational and MR studies. The potential anti-cancer benefits of coffee are attributed to its bioactive compounds, such as caffeine, chlorogenic acids, and diterpenes, which possess antioxidant and anti-inflammatory properties. These compounds may reduce oxidative stress, inhibit cancer cell proliferation, induce apoptosis, and modulate hormone levels. The review emphasizes the need for further research to clarify dose-response relationships, causal associations, and the biological mechanisms underlying these associations. While coffee consumption appears to contribute to cancer prevention and healthy aging, caution is warranted due to the increased risk of certain cancers, highlighting the complexity of its health effects.

Association of diabetes risk reduction diet with renal cancer risk in 101,755 participants: a prospective study

BACKGROUND

There is little prospective evidence exists about whether adherence to a diabetes risk reduction diet (DRRD) is related to a significant reduction in renal cancer risk. We sought to clarify whether adherence to DRRD was associated with a reduced risk of renal cancer in a US population.

METHODS

A population-based cohort of 101,755 American adults was identified from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. A DRRD score was calculated to assess adherence to this dietary pattern, where increased scores indicated greater adherence. The relationship between DRRD score and risk of renal cancer was assessed based on the hazard ratios (HRs) and 95% confidence intervals (CIs), which were both calculated using Cox regression. Non-linear association was determined through restricted cubic spline regression. Potential effect modifiers were identified through subgroup analyses.

RESULTS

Over a mean follow-up of 8.8 years, 446 renal cancers were detected. In this analysis, the fully adjusted model depicted a notable 29% reduction in the risk of renal cancer among individuals in the highest quartile of DRRD score in comparison with the lowest quartile individuals (HRQ4 vs. Q1: 0.71; 95% CI = 0.54, 0.94; Ptrend = 0.008). This association remained consistent across a series of sensitivity analyses. A non-linear inverse dose-response association between renal cancer risk with DRRD score was observed (Pnonlinearity = 0.026). Subgroup analyses showed that this favorable link was more prominent in participants with low Healthy Eating Index-2015 (Pinteraction = 0.015). Regarding the individual components of DRRD, a decrease in the risk of renal cancer was linked to increased intake of cereal fiber and whole fruit, and lower sugar-sweetened beverage consumption (all Ptrend < 0.05).

CONCLUSIONS

Our findings indicate that individuals adhering to DRRD are associated with a reduction in the risk of renal cancer.

The Chemopreventive Effects of Chlorogenic Acids, Phenolic Compounds in Coffee, against Inflammation, Cancer, and Neurological Diseases

Coffee is one of the most widely consumed beverages, which has several effects on the human body. In particular, current evidence suggests that coffee consumption is associated with a reduced risk of inflammation, various types of cancers, and certain neurodegenerative diseases. Among the various constituents of coffee, phenolic phytochemicals, more specifically chlorogenic acids, are the most abundant, and there have been many attempts to utilize coffee chlorogenic acid for cancer prevention and therapy. Due to its beneficial biological effect on the human body, coffee is regarded as a functional food. In this review article, we summarize the recent advances and knowledge on the association of phytochemicals contained in coffee as nutraceuticals, with a particular focus on phenolic compounds, their intake, and nutritional biomarkers, with the reduction of disease risk, including inflammation, cancer, and neurological diseases.

The Epigenetic Effects of Coffee

In this review, we discuss the recent knowledge regarding the epigenetic effects of coffee extract and the three essential active ingredients in coffee (caffeine, chlorogenic acid, and caffeic acid). As a popular beverage, coffee has many active ingredients which have a variety of biological functions such as insulin sensitization, improvement of sugar metabolism, antidiabetic properties, and liver protection. However, recent researches have shown that coffee is not only beneficial for human, but also bad, which may be due to its complex components. Studies suggest that coffee extract and its components can potentially impact gene expression via alteration of DNA methylation, histone modifications, and ncRNA expression; thus, exert long lasting impacts on the epigenome. More importantly, coffee consumption during pregnancy has been linked to multiple negative effects on offspring due to epigenetic modifications; on the other hand, it has also been linked to improvements in many diseases, including cancer. Therefore, understanding more about the epigenetic effects associated with coffee components is crucial to finding ways for improving human health.

Health Benefits of Coffee Consumption for Cancer and Other Diseases and Mechanisms of Action

Coffee is one of the most widely consumed beverages worldwide, and epidemiology studies associate higher coffee consumption with decreased rates of mortality and decreased rates of neurological and metabolic diseases, including Parkinson's disease and type 2 diabetes. In addition, there is also evidence that higher coffee consumption is associated with lower rates of colon and rectal cancer, as well as breast, endometrial, and other cancers, although for some of these cancers, the results are conflicting. These studies reflect the chemopreventive effects of coffee; there is also evidence that coffee consumption may be therapeutic for some forms of breast and colon cancer, and this needs to be further investigated. The mechanisms associated with the chemopreventive or chemotherapeutic effects of over 1000 individual compounds in roasted coffee are complex and may vary with different diseases. Some of these mechanisms may be related to nuclear factor erythroid 2 (Nrf2)-regulated pathways that target oxidative stress or pathways that induce reactive oxygen species to kill diseased cells (primarily therapeutic). There is evidence for the involvement of receptors which include the aryl hydrocarbon receptor (AhR) and orphan nuclear receptor 4A1 (NR4A1), as well as contributions from epigenetic pathways and the gut microbiome. Further elucidation of the mechanisms will facilitate the potential future clinical applications of coffee extracts for treating cancer and other inflammatory diseases.

Green tea and coffee consumption and risk of kidney cancer in Japanese adults

The study aimed to evaluate the association between green tea and coffee consumption and the risk of kidney cancer using data from a large prospective cohort study in Japan (the Japan Public Health Center-based Prospective Study: JPHC Study). A total of 102,463 participants aged 40-69 were followed during 1,916,421 person-years (mean follow-up period, 19 years). A total of 286 cases of kidney cancer (199 in men, 87 in women) were identified. Cox proportional hazards regression models were used to estimate hazard ratios (HRs) and 95% confidence intervals (95% CIs) while adjusting for potential confounders. No statistically significant association between green tea intake and kidney cancer risk was found in the total population. Among women who consumed more than five cups of green tea per day, a statistically significant decreased risk was shown with a HR of 0.45 (95% CI: 0.23-0.89), compared to women who rarely consumed green tea. For coffee consumption, the association of kidney cancer risk was not statistically significant. This large prospective cohort study indicated green tea intake may be inversely associated with kidney cancer risk in Japanese adults, particularly in Japanese women.

Coffee and caffeine consumption and risk of renal cell carcinoma: A Mendelian randomization study

Background

The association between coffee and caffeine consumption and the risk of renal cell carcinoma was inconsistent among observational studies, and whether these observed associations were causal remained unclear. Therefore, we performed two-sample Mendelian randomization (MR) study to assess the causal nature of the association.

Materials and methods

In this study, 12 and two independent single nucleotide polymorphisms (SNPs) related to coffee and caffeine consumption at a genome-wide significance level of p < 5 × 10^–8 were used as instrumental variables (IVs), respectively. Summary-level data for renal cell carcinoma were taken from the FinnGen consortium with up to 174,977 individuals, and the International Agency for Research on Cancer (IARC) with 13,230 individuals. We used inverse-variance weighted (IVW) as the main method, followed by the weighted median method, the MR-Egger regression method, and the MR robust adjusted profile score method. Outlier and pleiotropic variants were assessed by the MR Pleiotropy RESidual Sum and Outlier test and MR-Egger regression. We used meta-analysis methods in fixed-effects to combine the estimates from the two sources.

Results

The genetically predicted coffee consumption was not associated with the risk of renal cell carcinoma in the FinnGen consortium, and the relationship was consistent in the IARC consortium. The pooled odds ratio (OR) per 50% increase of coffee consumption was 0.752 [95% confidence interval (CI), 0.512–1.105; p = 0.147]. In addition, complementary analyses that separated the coffee-related SNPs according to their relationship with blood levels of caffeine metabolites (higher, lower, or unrelated) found no relationship with renal cell carcinoma. The results were consistent after excluding eight SNPs due to potential risk factors at genome-wide significance (p < 5 × 10^–8). Moreover, genetically predicted per 80-mg increase in caffeine consumption was not associated with the risk of renal cell carcinoma (pooled OR = 0.872, 95% CI: 0.676–1.125, p = 0.292).

Conclusion

Our MR study provided no convincing evidence for a causal effect between coffee and caffeine consumption and the risk of renal cell carcinoma. The associations for renal cell carcinoma need to be verified in well-powered studies.