Nut consumption and the risk of oesophageal squamous cell carcinoma in the Golestan Cohort Study

Iron, Copper, and Magnesium Concentration in Hair and Risk of Esophageal Cancer: A Nested Case-Control Study

BACKGROUND

An association has already been hypothesized between iron, copper, and magnesium status assessed through food frequency questionnaires (FFQs) and the risk of esophageal squamous cell carcinoma (ESCC). However, self-reported dietary assessment methods are prone to measurement errors. We studied the association between iron, copper, and magnesium status and ESCC risk, using hair samples as a long exposure biomarker.

METHODS

We designed a nested case-control study within the Golestan Cohort Study, that recruited about 50000 participants in 2004-2008, and collected biospecimens at baseline. We identified 96 incident cases of ESCC with available hair samples. They were age-matched with cancer-free controls from the cohort. We used inductively coupled plasma mass spectrometry (ICP-MS) to measure iron, copper, and magnesium concentrations in hair samples. We used multiple logistic regression models to determine odds ratios and 95% confidence intervals.

RESULTS

Median concentrations of iron, copper, and magnesium were 35.4, 19.3, and 41.7 ppm in cases and 25.8, 18.3, and 50.0 ppm in controls, respectively. Iron was significantly associated with the risk of ESCC in continuous analysis (OR=1.41, 95% CI=1.03-1.92), but not in the tertiles analyses (ORT3 vs. T1=1.81, 95% CI=0.77-4.28). No associations were observed between copper and magnesium and ESCC risk, in either the tertiles models or the continuous estimate (copper: ORT3 vs. T1=2.56, 95% CI=1.00-6.54; magnesium: ORT3 vs. T1=0.75, 95% CI=0.32-1.78).

CONCLUSION

Higher iron status may be related to a higher risk of ESCC in this population.

Diet Quality and Subsequent Incidence of Upper Gastrointestinal Cancers: Results from the Golestan Cohort Study

BACKGROUND

Recent evidence suggests overall diet quality, as assessed by dietary scores, may play a role in the development of upper gastrointestinal (UGI) cancers. However, the existing dietary scores are derived from high-income countries with different dietary habits than regions with the highest burden of UGI cancers, where limited data is available. This study aimed to investigate the association between overall diet quality and risk of esophageal and stomach cancers in a high-risk region for UGI cancers.

METHODS

We recruited 50045 individuals aged 40-75 between 2004-2008 from northeastern Iran and followed them annually through July 2020. Data on demographics, diet, and various exposures were collected using validated questionnaires. Diet quality was assessed by calculating the Healthy Eating Index (HEI), Alternative Healthy Eating Index (AHEI), Alternative Mediterranean Diet (AMED), Dietary Approaches to Stop Hypertension (DASH), and World Cancer Research Fund-American Institute for Cancer Research (WCRF-AICR) scores.

RESULTS

During an average 12 years of follow-up, 359 participants developed esophageal cancer and 358 developed stomach cancer. After adjustments, each standard deviation increase in baseline dietary scores was associated with up to 12% reduction in esophageal cancer risk and up to 17% reduction in stomach cancer risk. Esophageal cancer showed stronger inverse associations with adherence to AMED (HRQ4-vs-Q1=0.69 (0.49-0.98), P-trend=0.038). Stomach cancer showed stronger inverse correlation with WCRF-AICR (HRQ4-vs-Q1=0.58 (0.41-0.83), P-trend=0.004), and DASH (HRC4-vs-C1=0.72 (0.54-0.96), P-trend=0.041). These associations were comparable across different population subgroups. We did not observe significant associations between HEI and AHEI scores and UGI cancers in this population.

CONCLUSION

Despite the differences in consuming individual food groups, adherence to the available dietary recommendations (derived from high-income countries) was associated with lower risk for subsequent esophageal and gastric cancers in this high-risk population. Educating the public to have a healthy eating pattern might be an effective strategy towards prevention of UGI cancers in high-risk regions.

Antioxidant and Anti-Inflammatory Properties of Walnut Constituents: Focus on Personalized Cancer Prevention and the Microbiome

Walnuts have been lauded as a 'superfood', containing a remarkable array of natural constituents that may have additive and/or synergistic properties that contribute to reduced cancer risk. Walnuts are a rich source of polyunsaturated fatty acids (PUFAs: alpha-linolenic acid, ALA), tocopherols, antioxidant polyphenols (including ellagitannins), and prebiotics, including fiber (2 g/oz). There is a growing body of evidence that walnuts may contribute in a positive way to the gut microbiome, having a prebiotic potential that promotes the growth of beneficial bacteria. Studies supporting this microbiome-modifying potential include both preclinical cancer models as well as several promising human clinical trials. Mediated both directly and indirectly via its actions on the microbiome, many of the beneficial properties of walnuts are related to a range of anti-inflammatory properties, including powerful effects on the immune system. Among the most potent constituents of walnuts are the ellagitannins, primarily pedunculagin. After ingestion, the ellagitannins are hydrolyzed at low pH to release ellagic acid (EA), a non-flavonoid polyphenolic that is subsequently metabolized by the microbiota to the bioactive urolithins (hydroxydibenzo[b,d]pyran-6-ones). Several urolithins, including urolithin A, reportedly have potent anti-inflammatory properties. These properties of walnuts provide the rationale for including this tree nut as part of a healthy diet for reducing overall disease risk, including colorectal cancer. This review considers the latest information regarding the potential anti-cancer and antioxidant properties of walnuts and how they may be incorporated into the diet to provide additional health benefits.

Walnut consumption and health outcomes with public health relevance-a systematic review of cohort studies and randomized controlled trials published from 2017 to present

CONTEXT

Considering the accumulation of recent studies investigating the health effects of walnut consumption, both including and beyond cardiovascular health effects, a systematic review of this literature to investigate the strength of the evidence is warranted.

OBJECTIVE

To investigate associations between walnut consumption and outcomes with public health relevance (specifically all-cause mortality, type 2 diabetes, CVD, metabolic syndrome, obesity, cancer, neurological and mental health, musculoskeletal, gastrointestinal, and maternal disorders) and the effect on associated disease risk markers, reported in studies published from 2017 to present.

DATA SOURCES

MEDLINE, FSTA, CENTRAL, and Scopus were searched from 1 January 2017 to 5 May 2021.

DATA EXTRACTION

Human studies (cohort studies and RCTs) ≥3 weeks in duration comparing consumption of walnuts (whole, pieces, or 100% butter) to a control and measuring associations with relevant public health outcomes and disease risk markers were assessed. Key study characteristics were extracted independently by 2 investigators using a standardized table. The quality of the studies was assessed using the Cochrane Risk-of-Bias tool 2.0 and the Newcastle-Ottawa Scale.

DATA ANALYSIS

Only 1 RCT was considered to be at low risk of bias for any of its outcomes. The cohort studies were considered to be of moderate or high quality. The results were synthesized using vote counting, based on the direction of effect. Thirty-three articles, 23 describing RCTs (walnut dose ∼10-99 g/day, 1,948 subjects) and 10 describing cohort studies (∼675,928 subjects), were included. Vote counting could be performed for the blood lipids, cardiovascular function, inflammation- and hemostatic-related factors, markers of glucose metabolism, and body weight and composition outcome groupings. The results are presented in effect direction plots. With respect to blood lipids, results from 8/8 RCTs favoured walnuts, in accordance with associations with a reduced risk of CVD suggested by cohort studies; results from 6/6 RCTs favoured control with respect to body weight and composition, although most of these effects were small. This was contrary to cohort study results suggesting small benefits of walnut consumption on body weight. There was no overall consistent direction of effect for cardiovascular function, markers of glucose metabolism, or inflammation- and hemostatic-related factors.

CONCLUSIONS

Evidence published since 2017 is consistent with previous research suggesting that walnut consumption improves lipid profiles and is associated with reduced CVD risk. Evidence is accumulating in other areas, such as cognitive health, although more research is needed to draw firm conclusions.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD4202122.

Association between nut consumption and cancer risk: a meta-analysis

This study aims to conduct a meta-analysis and dose-response analysis of the relationship between nut intake and cancer risk and mortality. Electronic databases were searched. A meta-analysis was conducted to calculate the pooled effect sizes (ESs) with the corresponding 95% CIs, and a dose-response analysis was performed. A random-effects model was used in the statistical analysis. Two independent reviewers completed the full-text screening, data extraction, and quality assessment. We included 17 articles in the present meta-analysis. Total nuts intake was revealed to be significantly associated with reduced cancer risk (ES: 0.9; 95% CI: 0.86-0.95; P < 0.001) and cancer mortality (ES: 0.88; 95% CI: 0.85-0.92, P < 0.001), especially lung cancer risk (ES: 0.86; 95% CI: 0.81-0.91, P < 0.001) and gastric cancer risk (ES: 0.79; 95% CI: 0.68-0.91, P = 0.001). Moreover, a 10 g/d increment of tree nuts consumption was associated with a 20% cancer mortality reduction (ES: 0.80; 95% CI: 0.71-0.89; P < 0.0001). Nuts intake is significantly associated with the reduction of cancer risk and mortality. Especially, nuts intake is significantly associated with reduced lung cancer risk and gastric cancer risk. Noticeably, a 10 g/d increase in tree nuts intake is related to a 20% reduction in overall cancer mortality.

Association of Total Nut, Tree Nut, Peanut, and Peanut Butter Consumption with Cancer Incidence and Mortality: A Comprehensive Systematic Review and Dose-Response Meta-Analysis of Observational Studies

Data on the association of nut intake with risk of cancer and its mortality are conflicting. Although previous meta-analyses summarized available findings in this regard, some limitations may distort their findings. Moreover, none of these meta-analyses examined the dose-response associations of total nut intake with the risk of specific cancers as well as associations between specific types of nuts and cancer mortality. Therefore, this study aimed to summarize available findings on the associations of total nut (tree nuts and peanuts), tree nut (walnuts, pistachios, macadamia nuts, pecans, cashews, almonds, hazelnuts, and Brazil nuts), peanut (whole peanuts without considering peanut butter), and peanut butter consumption with risk of cancer and its mortality by considering the above-mentioned points. We searched the online databases until March 2020 to identify eligible articles. In total, 43 articles on cancer risk and 9 articles on cancer mortality were included in the current systematic review and meta-analysis. The summary effect size (ES) for risk of cancer, comparing the highest with lowest intakes of total nuts, was 0.86 (95% CI: 0.81, 0.92, P < 0.001, I2 = 58.1%; P < 0.01), indicating a significant inverse association. Such a significant inverse association was also seen for tree nut intake (pooled ES: 0.87, 95% CI: 0.78-0.96, P < 0.01, I2 = 15.8%; P = 0.28). Based on the dose-response analysis, a 5-g/d increase in total nut intake was associated with 3%, 6%, and 25% lower risks of overall, pancreatic, and colon cancers, respectively. In terms of cancer mortality, we found 13%, 18%, and 8% risk reductions with higher intakes of total nuts, tree nuts, and peanuts, respectively. In addition, a 5-g/d increase in total nut intake was associated with a 4% lower risk of cancer mortality. In conclusion, our findings support the protective association between total nut and tree nut intake and the risk of cancer and its mortality.

Meta-analysis of the association between nut consumption and the risks of cancer incidence and cancer-specific mortality

Previous studies have indicated a correlation between nut intake and cancer risk in humans. This meta-analysis aimed to determine the relationship between nut consumption and the risks of cancer incidence and mortality. The PubMed, Embase, and Web of Science databases were searched up to August 2019. Relative risks and 95% confidence intervals were calculated using random-effects and fixed-effects models. We included 38 studies on nut consumption and cancer risk and 9 studies on cancer-specific mortality. Compared with no nut intake, nut intake was associated with a lower cancer risk (Relative Risk=0.90; 95% confidence interval, 0.86–0.94). Inverse associations were observed with colorectal cancer, gastric cancer, pancreatic cancer, and lung cancer in subgroup analyses. Tree nut consumption was found to reduce cancer risk (Relative Risk=0.88; 95% confidence interval, 0.79–0.99). Dose-response curves suggested that protective benefits against cancer increased with increased nut intake (P=0.005, P-nonlinearity=0.0414). An inverse correlation with cancer-specific mortality (Odd Ratio=0.90; 95% confidence interval, 0.88–0.92) was observed. In conclusion, nut consumption is inversely associated with the risks of cancer incidence and mortality; a higher intake is significantly associated with a lower cancer risk.

10-Year Trends in Dietary Intakes in the High- and Low-Risk Areas for Esophageal Cancer: A Population-Based Ecological Study in Northern Iran

BACKGROUND

We assessed dietary intakes in the high- and low-risk areas for esophageal cancer (EC) in Golestan province, Northern Iran.

METHODS

Considering the EC rates, Golestan province was divided into high- and low-risk regions. Data on households’ food consumption were obtained from the Statistical Center of Iran. We used multivariable logistic regression to assess the relationships between consumption of main food and EC risk. Adjusted odds ratios (aOR) were calculated. Joint point program was used for time trend analysis and average annual percent changes (AAPC) were reported.

RESULTS

Overall, 11910 households were recruited during 2006-2015. 4710 (39.5%) households were enrolled from the high-risk region. There were significant positive relationships between high consumption of sweets (aOR = 1.62; 95% CI: 1.24-2.10), oil/fat (aOR = 1.36; 95% CI: 1.04-1.79), and red meat (aOR = 1.33; 95% CI: 1.07-1.65) with EC risk. We found significant negative relationships between high consumption of dairy products (aOR = 0.62; 95% CI: 0.46-0.82), vegetables (aOR = 0.66; 95% CI: 0.50-0.87) and fruit (aOR = 0.72; 95% CI: 0.55-0.95) with the risk of EC. Time trend analysis showed a significant increasing trend in the proportions of households with low consumption of vegetables (AAPC = 4.71, p = 0.01) and dairy products (AAPC = 5.26, p = 0.02) in the low-risk region for EC.

CONCLUSION

Dietary intakes may be important etiological factors for EC in Northern Iran. Further studies are warranted to assess the role of dietary factors in this high-risk population.

Nut Consumption and Risk of Cancer: A Meta-analysis of Prospective Studies

BACKGROUND

Epidemiologic studies have investigated the association between nut intake and risk for multiple cancers. However, current findings are inconsistent and no definite conclusion has been drawn from prospective studies. We therefore conducted this meta-analysis to evaluate the relationship between nut consumption and risk of cancer.

METHODS

Prospective studies reporting associations between nut intake and risk for all types of cancer were identified by searching Web of Science and PubMed databases up to June 2019. Risk ratios (RR) and 95% confidence intervals (CI) were extracted and then pooled across the studies using a random-effect model. A dose-response analysis was modeled by performing restricted cubic splines when data were available.

RESULTS

Thirty-three studies that included more than 50,000 cancer cases were eligible for the analysis. When comparing the highest with the lowest category of nut intake, high consumption of nuts was significantly associated with decreased risk of overall cancer (RR = 0.90; 95% CI, 0.85-0.95). The protective effect of nut consumption was especially apparent against cancers from the digestive system (RR = 0.83; 95% CI, 0.77-0.89). Among different nut classes, significant association was only obtained for intake of tree nuts. We also observed a linear dose-response relationship between nut consumption and cancer: Per 20 g/day increase in nut consumption was related to a 10% (RR = 0.90; 95% CI, 0.82-0.99) decrease in cancer risk.

CONCLUSIONS

Our analysis demonstrated an inverse association of dietary nut consumption with cancer risk, especially for cancers from the digestive system.

IMPACT

This study highlights the protective effect of nuts against cancer.

Turmeric, Pepper, Cinnamon, and Saffron Consumption and Mortality

Background Previous studies have reported the beneficial effects of spice consumption on lipid profiles, fasting glucose, and blood pressure, which suggests that spice consumption could affect the risk of cardiovascular disease, diabetes mellitus, and consequently mortality. The objective of this study was to evaluate the relationship between consumption of turmeric, black or chili pepper, cinnamon, and saffron with overall and cause-specific mortality in an adult population in Iran. Methods and Results We used data from the Golestan Cohort Study, which has followed 50 045 participants aged 40 to 75 years from baseline (2004-2008). After establishing the exclusion criteria, 44 398 participants were included in the analyses. Spice consumption data were extracted from the baseline Food Frequency Questionnaire. Cox models were used to estimate hazard ratios (HR) and 95% CI for overall and cause-specific mortality, comparing the ever consumers to the never consumers as a reference group for each type of spice (adjusted for known and suspected confounders). During 11 years of follow-up, 5121 people died. Turmeric consumption was associated with significantly reduced risk of overall mortality (HR=0.90, 95% CI=0.85-0.96) and cardiovascular mortality (HR=0.91, 95% CI=0.82-0.99). Black or chili pepper consumption was associated with significantly reduced risk of overall mortality (HR=0.91, 95% CI=0.86-0.98). Saffron consumption was associated with significantly reduced risk of overall (HR=0.85, 95% CI=0.77-0.94) and cardiovascular mortality (HR=0.79, 95% CI=0.68-0.92). We found no associations with cinnamon consumption or between any of these spices and cancer mortality. Conclusions Consuming turmeric or saffron was associated with decreased risk of overall and cardiovascular mortality. The hypothesis of a protective effect of spice consumption on mortality should be tested in other prospective studies.

Nut and Peanut Butter Consumption and Mortality in the National Institutes of Health-AARP Diet and Health Study

Although previous studies have shown inverse associations between nut consumption and mortality, the associations between nut consumption and less common causes of mortality have not been investigated. Additionally, about 50% of peanut consumption in the US is through peanut butter but the association between peanut butter consumption and mortality has not been thoroughly evaluated. The National Institutes of Health-AARP (NIH-AARP) Diet and Health Study recruited 566,398 individuals aged 50–71 at baseline in 1995–1996. A food-frequency questionnaire was used to evaluate nut and peanut butter consumption. Cox proportional hazard models were used to estimate hazard ratios and 95% confidence intervals for mortality using the non-consumers as reference groups and three categories of consumption. After excluding subjects with chronic diseases at baseline, there were 64,464 deaths with a median follow-up time of 15.5 years. We observed a significant inverse association between nut consumption and overall mortality (HR _{C4 vs C1} = 0.78, 95% CI = 0.76, 0.81, p ≤ 0.001). Nut consumption was significantly associated with reduced risk of cancer, cardiovascular, respiratory, infectious, renal and liver disease mortality but not with diabetes or Alzheimer’s disease mortality. We observed no significant associations between peanut butter consumption and all-cause (HR _{C4 vs C1} = 1.00, 95% CI = 0.98, 1.04, p = 0.001) and cause-specific mortality. In a middle-aged US population, nut intake was inversely associated with all-cause mortality and certain types of cause-specific mortality. However, peanut butter consumption was not associated with differential mortality.

A Prospective Study of Nut Consumption and Risk of Primary Hepatocellular Carcinoma in the U.S. Women and Men

Although increasing evidence suggests a potential beneficial effect of nut consumption on various diseases, no epidemiologic study has yet examined the association between nut consumption and risk of hepatocellular carcinoma (HCC). We prospectively examined this association in 88,783 women from the Nurses' Health Study and 51,492 men from the Health Professionals Follow-up Study. Nut consumption was assessed every 4 years using validated food frequency questionnaires. Multivariable HRs and 95% confidence intervals (95% CI) were estimated using Cox proportional hazards regression models after adjusting for HCC risk factors. After an average of 27.9 years of follow-up, we identified a total of 162 incident HCC cases. Higher total nut consumption was not significantly associated with HCC risk (the highest vs. lowest tertile intake, HR, 0.84; 95% CI, 0.56-1.26). For the same comparison, higher tree nut consumption was associated with a lower HCC risk (HR, 0.64; 95% CI, 0.43-0.95). We found nonsignificant inverse associations with consumption of walnuts, peanuts, and peanut butter. Overall, nut consumption was not strongly associated with HCC risk. There was a suggestive inverse association with tree nut consumption. Future studies should carefully consider hepatitis B or C virus infections and examine these associations in other racial/ethnic groups.