Coffee consumption and cancer risk in African Americans from the Southern Community Cohort Study

A systematic review and dose-response meta-analysis of prospective cohort studies on coffee consumption and risk of lung cancer

Studies on the association between coffee consumption and risk of lung cancer have been conflicting. The aim of this study was to systematically review the current evidence on the association between coffee consumption and risk of lung cancer and to quantify this association by performing a meta-analysis. A comprehensive systematic search was performed on online databases up to July 2023 investigating the association between coffee consumption and risk of lung cancer. All prospective cohort studies reporting odds ratios (ORs), rate or risk ratios (RRs), or hazard ratios (HRs) and 95% confidence intervals (CIs) in this context were included. The overall effect size was calculated using the random-effects model and statistical between-studies heterogeneity was examined using Cochrane's Q test and I2. A total of 14 prospective cohort studies were included in this systematic review and meta-analysis. We found a significant positive association between coffee consumption and risk of lung cancer (RR: 1.28; 95% CI: 1.12, 1.47). This association remained significant when we included a pooled analysis paper and excluded 5 cohort studies (RR: 1.37; 95% CI: 1.12, 1.66). We observed no proof of significant publication bias using Egger's test (P = 0.58). Moreover, dose-response analysis showed that each one cup/day increase in coffee consumption was related with a 6% higher lung cancer risk (RR: 1.06; 95% CI: 1.03, 1.09). In conclusion, we found a significant positive association between coffee consumption and risk of lung cancer.

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

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

Involvement of microRNA modifications in anticancer effects of major polyphenols from green tea, coffee, wine, and curry

Epidemiological studies have shown that consumption of green tea, coffee, wine, and curry may contribute to a reduced risk of various cancers. However, there are some cancer site-specific differences in their effects; for example, the consumption of tea or wine may reduce bladder cancer risk, whereas coffee consumption may increase the risk. Animal and cell-based experiments have been used to elucidate the anticancer mechanisms of these compounds, with reactive oxygen species (ROS)-based mechanisms emerging as likely candidates. Chlorogenic acid (CGA), curcumin (CUR), epigallocatechin gallate (EGCG), and resveratrol (RSV) can act as antioxidants that activate AMP-activated protein kinase (AMPK) to downregulate ROS, and as prooxidants to generate ROS, leading to the downregulation of NF-κB. Polyphenols can modulate miRNA (miR) expression, with these dietary polyphenols shown to downregulate tumor-promoting miR-21. CUR, EGCG, and RSV can upregulate tumor-suppressing miR-16, 34a, 145, and 200c, but downregulate tumor-promoting miR-25a. CGA, EGCG, and RSV downregulate tumor-suppressing miR-20a, 93, and 106b. The effects of miRs may combine with ROS-mediated pathways, enhancing the anticancer effects of these polyphenols. More precise analysis is needed to determine how the different modulations of miRs by polyphenols relate to the cancer site-specific differences found in epidemiological studies related to the consumption of foods containing these polyphenols.

Dietary polyphenols and the risk of colorectal cancer in the prospective Southern Community Cohort Study

BACKGROUND

Polyphenols are antioxidants with promising anticancer properties, but few studies have examined the associations of specific dietary polyphenols with colorectal cancer (CRC) risks or among Black individuals in the United States.

OBJECTIVES

We examined the associations between dietary polyphenols and CRC and assessed differences in these associations or polyphenol intakes by subgroups, including race (Black and White), that may contribute to cancer disparities.

METHODS

The Southern Community Cohort Study prospectively enrolled individuals from the southeastern United States during 2002-2009, most of whom had a low income or are Black. Validated FFQ data and polyphenol databases were used to estimate polyphenol intakes. Cox proportional hazards models were used to obtain HRs and 95% CIs for the highest compared to the lowest intake quintiles (Qs) of specific polyphenols. Median intakes of quintiles were used to obtain linear trends, and restricted cubic splines were used to obtain nonlinear trends. Subgroup analyses were conducted by cancer site, sex, race, household income, and BMI-defined obesity status.

RESULTS

Among 71,599 participants, the median polyphenol intake was lower for Black individuals (452 mg/day; IQR, 277-672 mg/day) than White individuals (958 mg/day; IQR, 587-1597 mg/day). A significant, inverse, nonlinear association was observed for total polyphenol intake with the CRC risk (HR, 0.57; 95% CI, 0.38-0.86; P = 0.008 comparing 650 mg/day of intake to 0 mg/day). In addition, inverse linear associations were observed for tyrosols and the CRC risk (HRQ5vsQ1, 0.68; 95% CI, 0.50-0.91; P = 0.0014) and for hydroxybenzoic acids and the rectal cancer risk (HRQ5vsQ1, 0.49; 95% CI, 0.29-0.82; P = 0.0007). Associations were consistent by sex, race, income, and BMI.

CONCLUSIONS

Increasing intakes of total polyphenols, tyrosols, and hydroxybenzoic acids were associated with decreased CRC or rectal cancer risks, and associations were consistent across subgroups. Differences in polyphenol intakes may contribute to the increased CRC incidence among Black US individuals.