No associations between fruit and vegetable consumption and pancreatic cancer risk: a meta-analysis of prospective studies

Effect of cruciferous vegetable intake on cancer: An umbrella review of meta-analysis

Previous systematic evaluations and meta-analyses of the relationship between cruciferous vegetable (CV) intake and cancer risk have yielded inconsistent results. Herein, we summarize and evaluate the existing data and examine the relationship between CV intake and cancer risk. We searched four databases for cancer risk as a key outcome indicator. AMSTAR-2 was used to evaluate the methodological quality of the included systematic reviews, PRISMA 2020 was used to evaluate the report quality, and corrected coverage area analysis was used to evaluate the duplication rate of the original documents. Overall, 22 meta-analyses involving 175 independent cancer studies were included. Evidence on lung, gastric, prostate, breast, endometrial, and ovarian cancer, as well as renal cell carcinoma, suggests a potential association between cancer and CV intake, which influences the risk of various cancers. Future research should focus on improving methods and techniques, controlling influencing factors, elucidating underlying mechanisms, and improving evidence quality to demonstrate the association between CV intake and cancer. The potential role of dietary CVs in cancer control has implications for public health policies.

Role of Natural Antioxidants in Cancer

The oxidative stress defined as an event caused by an imbalance between production and accumulation of reactive oxygen species (ROS), which lead to a damage in the structure of proteins, lipids, and DNA. Therefore, the production of ROS may alter the normal physiological process by provoking damage to multiple cellular organelles and processes. Oxidative stress has been linked to heart disease, cancer, respiratory diseases, immune deficiency, stroke, Parkinson's disease, and other inflammatory or ischemic conditions. Antioxidants are substances that can prevent or slow damage to cells and tissues caused by ROS, unstable molecules that the body produces as a reaction to environmental and other pressures. The β-carotene, catechins, flavonoids, polyphenols, lycopene, lutein, selenium, vitamins A, C, D, E, and zeaxanthin are all common types of antioxidants and found in plant-based foods, especially fruits and vegetables. Each antioxidant has its own role and can interact with others to process and remove free radicals efficiently. Several studies have been conducted to investigate whether the use of dietary antioxidant supplements is associated with decreased risks of developing cancer in humans, mixed results were reported. For instance, daily use of supplement such as vitamin c, vitamin E, β-Carotene, and minerals such as selenium and zinc have shown its effectiveness by reducing the risk of developing prostate cancer among men and skin cancer among women.

High intake of cruciferous vegetables reduces the risk of gastrointestinal cancers: results from observational studies

The relationship between cruciferous vegetables (CV) and the risk of gastrointestinal (GI) cancers has been extensively investigated. However, epidemiologic investigations have produced inconsistent results. This meta-analysis investigated the association between CV intake and the risk of GI cancers. Due to the heterogeneity, fixed- or random-effects models were used for the analyses. The final analysis included 81 articles covering 89 studies. In comparison to the lowest consumption categories, the highest consumption categories of CV were associated with a lower risk for all GI cancers [rate ratio (RR): 0.81, 95% confidence interval (95% CI) 0.76-0.87]. Compared to a CV intake of 75 g/day, subjects with CV intake <75 g/day experienced a 7% reduction in risk (RR: 0.93; 95% CI: 0.84-0.96) for each 50 g increase in consumption. A negative correlation was identified between CV intake and the risk of esophageal cancer, gastric cancer, liver cancer, pancreatic cancer, and colorectal cancer (CRC), but not gallbladder cancer (RR: 0.70; 95% CI: 0.38-1.27). High intake of broccoli and cabbage was associated with a decreased risk of gastric cancer (RR: 0.64; 95% CI: 0.47-0.87) and gallbladder cancer (RR: 0.46; 95% CI: 0.29-0.75). These results confirm the association between high intake of CV with a reduced risk of GI cancers.

Dietary Factors and Pancreatic Cancer Risk: An Umbrella Review of Meta-Analyses of Prospective Observational Studies

Dietary factors may be associated with the occurrence of pancreatic cancer. This umbrella review aimed to review and grade the evidence for the associations between dietary factors and pancreatic cancer risk. We searched PubMed, EMBASE, Web of Science, Scopus, Cochrane Database of Systematic Reviews, and CINAHL for eligible literature. We included meta-analyses of randomized controlled trials (RCTs) or prospective observational studies. We used AMSTAR-2, a measurement tool to assess systematic reviews, to evaluate the methodological quality of the included meta-analyses. For each association, we calculated the summary effect size, 95% CI, heterogeneity, number of cases, 95% prediction interval, small-study effect, and excess significance bias. The protocol for this review was registered in the PROSPERO database (CRD42022333669). We included 41 meta-analyses of prospective observational studies describing 59 associations between dietary factors and pancreatic cancer risk. None of the retrieved meta-analyses included RCTs. No association was supported by convincing or highly suggestive evidence; however, there was suggestive evidence of a positive association between fructose intake and pancreatic cancer risk. There was weak evidence for an inverse association of nuts intake or adherence to the Mediterranean diet with pancreatic cancer incidence, and for positive associations between a higher intake of red meat or heavy alcohol intake and pancreatic cancer incidence. The remaining 54 associations were nonsignificant. Consistent with the American Institute for Cancer Research review, this umbrella review found that regular consumption of nuts and reduced intake of fructose, red meat, and alcohol were associated with a lower risk of pancreatic cancer. Emerging weak evidence supported an inverse association between adherence to the Mediterranean diet and pancreatic cancer risk. As some associations were rated as weak and most were considered nonsignificant, further prospective studies are needed to investigate the role of dietary factors and risk of pancreatic cancer. Adv Nutr 2023;xx:xx-xx.

What Dietary Patterns and Nutrients are Associated with Pancreatic Cancer? Literature Review

This narrative review summarizes the main findings of observational studies (case-control and cohort) as well as systematic reviews and meta-analyses on the role of nutrients and dietary patterns on pancreatic cancer (PC) risk and elucidates possible mechanisms for the association between nutrients or specific food components and the risk of PC. A literature search of MEDLINE (PubMed), Google Scholar, ScienceDirect, and Scopus was performed. An extensive search of related articles published in the English language from 1985 to 2022 was carried out. Our search included macro- and micronutrient intake as well as dietary patterns associated with PC. In conclusion, the consumption of a diet high in nutrients such as sugar, fats, and red and processed meats can increase the risk of PC. Conversely, a high dietary intake of fresh fruit and vegetables and their associated nutrients like fiber, antioxidants, and polyphenols may prevent PC. Dietary patterns loaded with red and processed meats were also linked to an increased risk of PC, whereas dietary patterns rich in plant-based foods like vegetables, fruits, whole grains, and legumes were associated with a reduced risk of PC. Dietary fiber, fat-soluble vitamins, water-soluble vitamins, and minerals might also play a protective role against PC.

Cruciferous vegetable consumption and multiple health outcomes: an umbrella review of 41 systematic reviews and meta-analyses of 303 observational studies

Background: Epidemiological studies evaluating the associations between the consumption of cruciferous vegetables (CV) and diverse health outcomes have generated inconsistent findings. Therefore, we carried out an umbrella review to systematically summarize existing evidence on this topic. Methods: This study had been registered at PROSPERO (no. CRD42021262011). Relevant systematic reviews and meta-analyses of observational studies were identified by searching PubMed, Web of science, and Embase databases from inception up to March 15, 2021. Observational studies investigating the association between CV intake and multiple health outcomes in humans were eligible for inclusion. The validated AMSTAR (A Measurement Tool to Assess Systematic Reviews) instrument was utilized for assessing the methodological quality of the included systematic reviews. For each meta-analysis, we assessed the summary effect size by using fixed and random effects models, 95% prediction intervals, heterogeneity, evidence of small-study effects, and excess significance bias. Results: Our umbrella review included 41 meta-analyses of 303 individual studies involving 13 394 722 participants. Twenty-four health outcomes including cancers (n = 23), cardiovascular disease (n = 12), mortality (n = 5), and metabolic diseases (n = 1) were evaluated. The summary random effects estimates were significant at P < 0.05 in 24 meta-analyses - all of which reported decreased risks of health outcomes. All were of moderate methodological quality in our study. Of the 41 meta-analyses, we observed suggestive evidence for beneficial associations between gastric cancer, lung cancer, endometrial cancer, and all-cause mortality. Moreover, 16 associations were supported by weak evidence, including breast cancer, lung cancer, renal cell carcinoma, bladder cancer, prostate cancer, ovarian cancer, endometrial cancer, colon cancer, colorectal adenoma, colorectal neoplasm, non-Hodgkin lymphoma, and total cancer. Conclusions: It revealed that CV intake might be associated with beneficial effects on several health-related outcomes (gastric cancer, lung cancer, endometrial cancer, and all-cause mortality). Other associations could be genuine, but substantial uncertainty remains. Additional studies are needed to evaluate the relationship between the consumption of CV and various health outcomes as well as robust randomized controlled trials in the future.

Diabetes risk reduction diet and the risk of pancreatic cancer

PURPOSE

To evaluate the role of a diabetes risk reduction diet (DRRD) on pancreatic cancer risk.

METHODS

We used data from a hospital-based case-control study conducted in Italy between 1991 and 2008; the study included 326 incident pancreatic cancer cases and 652 controls matched by age, gender and study center. Subjects' usual diet was collected through a valid and reproducible food frequency questionnaire. A DRRD score was derived from 8 dietary components: cereal fiber, total fruit, coffee, polyunsaturated to saturated fats ratio and nuts (higher score for higher intake), and dietary glycemic index, red/processed meat and sugar-sweetened beverages/fruit juices (higher score for lower intake). The score ranged 8-37, with higher values indicating greater DRRD adherence. Odds ratios (ORs) of pancreatic cancer according to the DRRD score were estimated using multiple conditional logistic regression models.

RESULTS

After allowance for confounding factors, the DRRD score was inversely related to pancreatic cancer risk, with ORs of 0.55 (95% confidence interval, CI 0.38-0.80) for the highest versus the lowest score tertile (p for trend across tertiles = 0.002) and 0.84 (95% CI 0.75-0.95) for a 3-point score increment. The exclusion of diabetic subjects and additional adjustment for vegetable intake did not change the results. Inverse associations were observed in subgroups defined by age, gender, education, body mass index, smoking and total energy intake.

CONCLUSION

Study findings suggest a protective role of high adherence to a DRRD on pancreatic cancer risk.

Total Antioxidant Capacity and Pancreatic Cancer Incidence and Mortality in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial

BACKGROUND

Total antioxidant capacity (TAC) reflects an individual's overall antioxidant intake. We sought to clarify whether higher TAC is associated with lower risks of pancreatic cancer incidence and mortality in the U.S. general population.

METHODS

A total of 96,018 American adults were identified from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. A ferric-reducing ability of plasma score was used to reflect an individual's TAC intake from diet and/or supplements. Cox regression was used to calculate hazard ratios (HR) for pancreatic cancer incidence, and competing risk regression was used to calculate subdistribution HRs for pancreatic cancer mortality. Restricted cubic spline regression was used to test nonlinearity.

RESULTS

A total of 393 pancreatic cancer cases and 353 pancreatic cancer-related deaths were documented. Total (diet + supplements) TAC was found to be inversely associated with pancreatic cancer incidence (HR _{quartile 4 vs. quartile 1} = 0.53; 95% confidence interval, 0.39-0.72; P _trend = 0.0002) and mortality (subdistribution HR _{quartile 4 vs. quartile 1} = 0.52; 95% confidence interval 0.38-0.72; P _trend = 0.0003) in a nonlinear dose-response manner (all P _nonlinearity < 0.01). Similar results were observed for dietary TAC. No association of supplemental TAC with pancreatic cancer incidence and mortality was found.

CONCLUSIONS

In the U.S. general population, dietary but not supplemental TAC level is inversely associated with risks of pancreatic cancer incidence and mortality in a nonlinear dose-response pattern.

IMPACT

This is the first prospective study indicating that a diet rich in antioxidants may be beneficial in decreasing pancreatic cancer incidence and mortality.