Maté consumption and the risk of esophageal squamous cell carcinoma: a meta-analysis

Role of diet in the risks of esophageal adenocarcinoma and squamous cell carcinoma: an updated umbrella review

PURPOSE

This updated umbrella review aimed to evaluate the evidence regarding the associations between dietary factors and the risks of esophageal squamous cell carcinoma (ESCC) and esophageal adenocarcinoma (EAC).

METHODS

The PubMed, Embase, Cochrane Library, and Web of Science databases were searched to identify relevant studies. The quality of the included meta-analyses was evaluated using A MeaSurement Tool to Assess systematic Reviews 2 (AMSTAR 2). For each association, the number of cases, random effects pooled effect size, 95% confidence intervals (CIs), heterogeneity, 95% prediction interval (PrI), small-study effect, and excess significance bias were recalculated to determine the evidence level.

RESULTS

We identified 33 meta-analyses describing 58 dietary factors associated with ESCC and 29 meta-analyses describing 38 dietary factors associated with EAC. There was convincing evidence regarding the association of 2 dietary factors (areca nut and high alcohol) with the risk of ESCC. There was highly suggestive evidence regarding the association of only 1 dietary factor (healthy pattern) with the risk of ESCC. There was suggestive evidence regarding the association of 11 dietary factors with the risk of ESCC, including fruit, citrus fruit, vegetables, pickled vegetables, maté tea, moderate alcohol, hot beverages and foods, hot tea, salt, folate, and vitamin B6. There was convincing evidence regarding the association of one dietary factor (vitamin B6) with the risk of EAC. There was suggestive evidence regarding the association of 4 dietary factors with the risk of EAC, including processed meat, dietary fibre, carbohydrate, and vitamin B12. The convincing evidence regarding the associations between dietary factors and the risks of ESCC and EAC remained robust in sensitivity analyses.

CONCLUSIONS

This umbrella review highlighted convincing evidence regarding the associations of areca nut and high alcohol with a higher risk of ESCC. Additionally, an association between vitamin B6 and a decreased risk of EAC was observed. Further research is needed to examine the dietary factors with weak evidence regarding their associations with ESCC and EAC.

Dairy consumption and risk of esophagus cancer in the prostate, lung, colorectal, and ovarian cohort

Background

Epidemiological studies provide limited information on the relationship between dairy consumption and the incidence of esophagus cancer (EC). We examined whether eating dairy foods is associated with a lower risk of EC in an American population.

Methods

In our study, we analyzed data from the Prostate, Lung, Colorectal, and Ovarian (PLCO) cancer screening trial, which included 101,723 subjects. Dairy product consumption was assessed using a dietary history questionnaire. We used Cox regression and restricted cubic splines to assess whether dairy consumption is associated with EC incidence.

Results

A total of 154 EC cases were identified after a median follow-up of 12.2 years. After adjusting for confounders, we discovered no statistically significant correlation between total dairy product consumption and EC risk (HR with 95% CI for ≥1.79 servings/day vs. ≤0.6 servings/day: 0.83, 0.50-1.38; p for trend = 0.465). Additionally, no associations were found between EC risk and other dairy foods such as milk, yogurt, and cheese.

Conclusion

We concluded that the findings of the PLCO cohort do not suggest dairy consumption reduces the risk of EC.

Systematic review: the etiology of esophageal squamous cell carcinoma in low-income settings

Esophageal carcinoma causes over 380 000 deaths per year, ranking sixth worldwide in mortality amongst all malignancies. Globally, the squamous cell subtype is most common and accounts for 80% of esophageal cancers. Nonetheless, esophageal squamous cell carcinoma is much more poorly understood than esophageal adenocarcinoma, including what is driving such high prevalences, why it often presents in young patients, and shows such marked geographical delineations Areas covered: The current literature was searched for articles focusing on aetiopathogenesis of squamous cell esophageal carcinoma via a systematic review, particularly in low-resource settings. This was supplemented by papers of interest known to the authors. Expert commentary: Current putative mechanisms include polycyclic aromatic hydrocarbons, nitrosamines, acetaldehyde, cyclo-oxygenase-2 pathways, androgen and their receptor levels, as well as smoking & alcohol, micronutrient deficiencies and diet, mycotoxins, thermal damage, oral hygiene and microbiotal factors, inhaled smoke, viral infections such as HPV, and chronic irritative states. Etiology is likely multifactorial and varies geographically. Though smoking and alcohol play a predominant role in high-income settings, there is strong evidence that mycotoxins, diet and temperature effects may play an under-recognized role in low and middle-income settings.

Polycyclic aromatic hydrocarbons as a potential source of carcinogenicity of mate

Drinking mate, an infusion of the herb ilex paraguariensis, is very common in several South American countries, and has been associated with an increased risk of esophageal cancer. This increased risk may be attributed to drinking mate very hot, or to mate's potentially carcinogenic contaminants, such as polycyclic aromatic hydrocarbons (PAHs). Mate leaves are often dried via smoking, and therefore commercial samples may have high amounts of PAHs. We found 10 original articles that had measured PAHs in commercial dry samples, and nearly all found very high mass fractions. Most studies found benzo[a]pyrene mass fractions to be over 25 ng/g, and some found levels up to 600 ng/g. However, carcinogenic PAHs are often hydrophobic, and may not readily transfer into infusions. Seven articles studied transfer rates, and these rates varied from 1 to 50%, depending on the methods employed. Further careful studies of transfer rates in situations that mimic real life drinking of mate are recommended. Also, further studies of biological indicators of PAH exposure, particularly in randomized experiments, and analyzing DNA from tumor samples of mate drinkers are recommended.

Maté consumption association with upper aerodigestive tract cancers: A systematic review and meta-analysis

Maté is a beverage regularly consumed by Latin American populations. Upper aerodigestive tract (UADT) cancers are frequent in this region and are suspected to be associated with maté consumption. The aim of this systematic review and meta-analysis was to answer a focused question: "Is there an association between maté consumption and occurrence of the UADT cancer?". Studies investigating any association between maté consumption and occurrence of UADT cancer were included. Out of the 569 studies, 18 met the inclusion criteria for qualitative and 15 for quantitative analysis. An increased odds was observed regarding maté consumption and overall occurrence of UADT cancer (OR = 2.24; 95%CI = 1.74-2.87). Consistent evidence of a positive association was found for all UADT subsites, oral, pharynx, esophagus and larynx. No differences in effect were found between consumption of cold/warm and hot/very hot mate (OR = 1.08; 95%CI = 0.83-1.41). Consumption of more than one liter of maté per day was associated with increased odds of having UADT cancer compared to an intake of less than one liter per day (OR = 1.72; 95%CI = 1.47-2.01). According to published data, regardless of the temperature, maté consumption significantly increased the odds of occurrence of UADT cancer.

Identification of spleen tyrosine kinase as a potential therapeutic target for esophageal squamous cell carcinoma using reverse phase protein arrays

The vast majority of esophageal cancers in China, India and Iran are esophageal squamous cell carcinomas (ESCC). A timely diagnosis provides surgical removal as the main therapeutic option for patients with ESCC. Currently, there are no targeted therapies available for ESCC. We carried out reverse phase protein array-based protein expression profiling of seven ESCC-derivedcell lines and a non-neoplastic esophageal epithelial cell line (Het-1A) to identify differentially expressed proteins in ESCC. SYK non-receptortyrosine kinase was overexpressed in six out of seven ESCC cell lines that were used in the study. We evaluated the role of SYK in ESCC using the pharmacological inhibitor entospletinib (GS-9973) and siRNA-based knock down studies. Entospletinib is a selective inhibitor of SYK, which is currently being evaluated in phase II clinical trials for hematological malignancies. Using in vivo subcutaneous tumor xenografts in mice, we demonstrate that treatment with entospletinib significantly inhibits tumor growth. Further clinical studies are needed to prove the efficacy of entospletinib as a targeted therapeutic agent for treating ESCC.

Identification of spleen tyrosine kinase as a potential therapeutic target for esophageal squamous cell carcinoma using reverse phase protein arrays

The vast majority of esophageal cancers in China, India and Iran are esophageal squamous cell carcinomas (ESCC). A timely diagnosis provides surgical removal as the main therapeutic option for patients with ESCC. Currently, there are no targeted therapies available for ESCC. We carried out reverse phase protein array-based protein expression profiling of seven ESCC-derivedcell lines and a non-neoplastic esophageal epithelial cell line (Het-1A) to identify differentially expressed proteins in ESCC. SYK non-receptortyrosine kinase was overexpressed in six out of seven ESCC cell lines that were used in the study. We evaluated the role of SYK in ESCC using the pharmacological inhibitor entospletinib (GS-9973) and siRNA-based knock down studies. Entospletinib is a selective inhibitor of SYK, which is currently being evaluated in phase II clinical trials for hematological malignancies. Using in vivo subcutaneous tumor xenografts in mice, we demonstrate that treatment with entospletinib significantly inhibits tumor growth. Further clinical studies are needed to prove the efficacy of entospletinib as a targeted therapeutic agent for treating ESCC.

Heavy drinkers of Ilex paraguariensis beverages show lower lipid profiles but higher body weight

Obesity is a widely recognized risk factor for several diseases, reaching an epidemic magnitude worldwide. Natural polyphenols may improve blood lipids and body weight, but their clinical relevance in the general population remains unclear. Thus, we aimed to analyze the relationship of intake of Ilex paraguariensis (I. paraguariensis) beverages to lipid profiles and body weight in a large patient population. Patients were recruited to participate in an educational program to change habits to a healthy lifestyle. Anamnesis, clinical and laboratory assessments were conducted at study enrollment and during follow‐up. I. paraguariensis beverages were defined according to preparation as obtained by repeated cold water extraction (CWE), hot water infusions, or water and sugar decoction. Heavy drinkers were defined as those persons consuming >1 L/day of one or more preparation types. Participants (N = 18,287) aged ≥18 years entered the study. Overall prevalence of I. paraguariensis consumption was 91.2%. All three forms were drunk by 35.7%, whereas CWE + hot water infusion and CWE alone by 28.4% and 14.5% participants, respectively. Heavy CWE drinkers had lower total cholesterol (191.4 ± 49.4 vs. 194.6 ± 48.3 mg/dl, p = .02) and lower low‐density lipoprotein cholesterol (118.6 ± 38.9 vs. 121.2 ± 47.1 mg/dl, p = .001), but body weight was higher (81.1 ± 16.8 vs. 77.2 ± 16.4 kg, p < .0001) compared with moderate drinkers. Fasting glucose was lower (104.5 ± 48.7 vs. 107.2 ± 49.5 mg/dl, p < .001), and consumption of carbohydrates was higher (36.3% vs. 28.7%, p < .001). A low‐lipids high‐body‐weight paradox could be observed in a population of heavy drinkers of I. paraguariensis beverages. Induced hypoglycemia and compensatory higher intake of refined carbohydrates may represent a possible cause.

Modifiable factors and esophageal cancer: a systematic review of published meta-analyses

There are marked differences in the etiology of the major histological types of esophageal cancer (EC)-squamous cell carcinomas (ESCC) and adenocarcinomas (EAC). This study aimed to summarize the current scientific knowledge on modifiable risk factors for EC, by histological type, through a systematic review of meta-analyses referenced in PubMed and ISI Web of Knowledge. We identified 100 meta-analyses on risk factors for ESCC (n = 54), EAC (n = 43), or EC (n = 51). ESCC risk significantly increased with alcohol and maté drinking, smoking, red and processed meat consumption and human papillomavirus infection, while it was negatively associated with body mass index and consumption of fruit, vegetables, white meat, folate, and some carotenoids. Cessation of drinking and smoking significantly reduced ESCC risk. For EAC, an increased risk was reported for smoking, body mass index, and red and processed meat consumption, while risk decreased with Helicobacter pylori infection, low/moderate alcohol drinking, physical activity, and consumption of fruit, vegetables, folate, fiber, beta-carotene, and vitamin C. Differences in results between meta-analyses and mechanisms underlying some of the associations found are discussed. This work reinforces the importance of a separate assessment of EC subtypes to allow for a proper evaluation of incidence trends and planning of prevention/control interventions.

Urinary Concentrations of Polycyclic Aromatic Hydrocarbon Metabolites in Maté Drinkers in Rio Grande do Sul, Brazil

Background: Consumption of maté, an infusion of the herb Ilex paraguariensis (yerba maté), is associated with increased risk of esophageal squamous cell carcinoma (ESCC), but the carcinogenic mechanism is unclear. Commercial brands of yerba maté contain high levels of carcinogenic polycyclic aromatic hydrocarbons (PAHs), which are acquired during the traditional drying process. The purpose of this study was to characterize exposure to PAHs in maté drinkers over a wide range of maté consumption.Methods: We recruited 244 adults who answered a questionnaire and collected a fasting spot urine specimen. We quantified urinary concentrations of seven PAH metabolites and assessed associations between self-reported recent maté consumption and urinary PAH metabolites by multivariate regression.Results: Recent maté consumption showed a significant dose-response association with 6 of 7 PAH metabolites in unadjusted models (P_trend < 0.05). After adjustment for creatinine and potential confounders, concentrations of 2-naphthol, 1-hydroxyphenanthrene, and the sum of 2- and 3-hydroxyphenanthrene remained significantly associated with recent maté intake. The sum of the urinary concentrations of the phenanthrene metabolites was similar or higher among maté drinkers who did not smoke than among smokers who did not drink matéConclusions: Urinary concentrations of PAH metabolites were significantly associated with self-reported amounts of recent maté intake, and drinking maté increased urinary concentrations of some PAH metabolites as much as smoking cigarettes.Impact: Drinking maté is a source of exposure to potentially carcinogenic PAHs, consistent with the hypothesis that the PAH content of maté may contribute to the increased risk of ESCC in maté drinkers. Cancer Epidemiol Biomarkers Prev; 27(3); 331-7. ©2017 AACR.

Factors associated with the high prevalence of oesophageal cancer in Western Kenya: a review

Oesophageal carcinoma (OC) is highly prevalent in Western Kenya especially among the members of the Kalenjin community who reside in the Northern and Southern areas of the Rift Valley. Previous authors have suggested potential association of environmental and genetic risk factors with this high prevalence. The environmental factors that have been suggested include contamination of food by mycotoxins and/or pesticides, consumption of traditional alcohol (locally referred to “Busaa” and “Chan’gaa”), use of fermented milk (“Mursik”), poor diet, tobacco use and genetic predisposition. The aim of this paper is to critically examine the potential contribution of each of the factors that have been postulated to be associated with the high prevalence of the disease in order to establish the most likely cause. We have done this by analyzing the trends, characteristics and behaviours that are specifically unique in the region, and corroborated this with the available literature.

From our findings, the most plausible cause of the high incidence of OC among the Kalenjin community is mycotoxins, particularly fumonisins from the food chain resulting from poor handling of cereals; particularly maize combined with traditional alcohol laced with the toxins interacting synergistically with other high-risk factors such as dietary deficiencies associated alcoholism and viral infections, especially HPV. Urgent mitigating strategies should be developed in order to minimize the levels of mycotoxins in the food chain.

Antiproliferative and cytotoxic effects of green coffee and yerba mate extracts, their main hydroxycinnamic acids, methylxanthine and metabolites in different human cell lines

This work aimed at studying the effects of green coffee bean (GCBE) and yerba mate (YME) extracts, their main phenolic components (5-caffeoylquinic acid, 5-CQA; 3,5-dicaffeoylquinic acid, 3,5-DCQA) and metabolites (ferulic acid, FA; caffeic acid, CA; dihydrocaffeic acid, DHCA; and dihydroferulic acid, DHFA) along with caffeine (CAF) on the viability and proliferation of different human cell lines. Extracts (10-1000 μg/mL) and standards (10-1000 μM) were assayed in colon (Caco-2), lung (A549), oesophageal (OE-33), urinary bladder (T24) human carcinoma cells, and a non-cancer cell line (CCD-18Co). YME significantly reduced viability of cancer cells at all assayed concentrations, the higher doses also reducing cell proliferation. GCBE effects on cell viability were more effective at 100 and 1000 μg/mL, showing modest effects on cell proliferation. The highest doses of 5-CQA and 3,5-DCQA reduced cell viability and proliferation in all cell lines, whereas FA, DHCA and DHFA had lower and variable effects. Caffeine had no effect. Dietary-attainable concentrations (0.1, 1 and 10 μg/mL) of YME were tested for cytotoxicity and reactive oxygen species generation, showing no cytotoxic effect. Low concentrations of all tested compounds were non-cytotoxic to CCD-18Co cells.

CONCLUSION

YME and to a lower degree GCBE, their phenolic components and metabolites may decrease cancer cell viability and proliferation.

Epidemiology, etiology, and prevention of esophageal squamous cell carcinoma in China

Esophageal cancer is one of the most fatal diseases worldwide mainly because of its rapid progression and poor prognosis. Although the incidence of esophageal adenocarcinoma has markedly risen in North America and Europe in the past several decades, esophageal squamous cell carcinoma is still the predominant subtype of esophageal cancer, especially in China. It accounts for more than 90% of all esophageal squamous cell carcinoma cases in China. Geographical differentiation is one of the most distinctive characteristics of esophageal cancer. The progression, risk factors, and prognosis of these two subtypes of esophageal cancer differ. This study reviews the epidemiology, etiology, and prevention of esophageal squamous cell carcinoma in China, thereby providing systematic references for policy-makers who will decide on issues of esophageal cancer prevention and control.

The burden of oesophageal cancer in Central and South America

RATIONALE AND OBJECTIVE

Oesophageal cancer shows marked geographic variations and is one of the leading causes of cancer death worldwide. We described the burden of this malignancy in Central and South America.

METHODS

Regional and national level incidence data were obtained from 48 population-based cancer registries in 13 countries. Mortality data were obtained from the WHO mortality database. Incidence of oesophageal cancer by histological subtype were available from high-quality population-based cancer registries.

RESULTS

Males had higher incidence and mortality rates than females (male-to-female ratios: 2-6:1 and 2-5:1). In 2003-2007, the highest rates were in Brazil, Uruguay, Argentina and Chile. Mortality rates followed the incidence patterns. Incidence of oesophageal squamous cell carcinoma (SCC) was higher than adenocarcinoma (AC), except in females from Cuenca (Ecuador). SCC and AC incidence were higher in males than females, except in the Region of Antofagasta and Valdivia (Chile), Manizales (Colombia) and Cuenca (Ecuador). Incidence and mortality rates tended to decline in Argentina, Chile, Brazil (incidence) and Costa Rica from 1997 to 2008.

CONCLUSION

The geographic variation and sex disparity in oesophageal cancer across Central and South America may reflect differences in the prevalence of tobacco smoking and alcohol consumption which highlights the need to implement and/or strengthen tobacco and alcohol control policies. Maté consumption, obesity, diet and Helicobacter pylori infection may also explain the variation in oesophageal cancer rates but these relationships should be evaluated. Continuous monitoring of oesophageal cancer rates is necessary to provide the basis for cancer prevention and control in the region.

Dietary and demographical risk factors for oesophageal squamous cell carcinoma in the Eastern Anatolian region of Turkey where upper gastrointestinal cancers are endemic

BACKGROUND

Oesophageal squamous cell carcinoma (ESCC) is endemic in the Eastern Anatolian region of Turkey. The present study was performed to identify risk factors for ESCC that specifically reflect the demography and nutritional habits of individuals living in this region.

MATERIALS AND METHODS

The following parameters were compared in 208 ESCC patients and 200 control individuals in the Eastern Anatolian region: age, sex, place of living, socioeconomic level, education level, smoking, alcohol intake, nutritional habits, and food preservation methods.

RESULTS

The mean age of ESCC patients was 56.2 years, and 87 (41.8%) were 65 years-old or older. The ratio of women to men in the patient group was 1.39/1. ESCC patients consumed significantly less fruit and yellow or green vegetables and more hot black tea, 'boiled yellow butter', and mouldy cheese than did control individuals. Residence in rural areas, smoking, and cooking food by burning animal manure were also significantly associated with ESCC.

CONCLUSIONS

The consumption of boiled yellow butter and mouldy cheese, which are specific to the Eastern Anatolian region, and the use of animal manure for food preparation were identified as risk factors in this region. Further studies are required to potentially identify the carcinogenic substances that promote the development of ESCC in this region.

Hot Food and Beverage Consumption and the Risk of Esophageal Cancer: A Meta-Analysis

CONTEXT

Esophageal cancer is a neoplasm with a poor prognosis. Its two histologic subtypes, esophageal squamous cell carcinoma (ESCC) and esophageal adenocarcinoma (EAC), have been associated with different risk factors. The possibility of an association between the consumption of hot food and beverages and esophageal cancer, especially ESCC, has long been suspected, presenting a potentially modifiable risk factor. A meta-analysis of existing observational studies was performed to provide a quantitative estimate of the risk of esophageal cancer associated with the consumption of hot food and drink.

EVIDENCE ACQUISITION

A search was conducted through MEDLINE, PubMed, EMBASE, and Current Contents Connect to November 11, 2014. Pooled ORs and 95% CIs were calculated using a random effects model for the risk of esophageal cancer associated with the consumption of hot food and drink. Subgroup analyses were conducted for ESCC and EAC, as well as for studies that adjusted for tobacco smoking and alcohol consumption, two well-recognized risk factors for ESCC.

EVIDENCE SYNTHESIS

Consumption of hot food and drink was associated with an increased risk of any esophageal cancer (OR=1.90, 95% CI=1.46, 2.48). Heterogeneity was observed. There was an increased risk of ESCC (OR=2.29, 95% CI=1.79, 2.93), which remained even after adjusting for significant confounding variables (OR=2.39, 95% CI=1.71, 3.33). The relationship was not significant for EAC.

CONCLUSIONS

The consumption of hot food and beverages was associated with an increased risk of esophageal cancer, particularly ESCC.

Facial flushing response to alcohol and the risk of esophageal squamous cell carcinoma: A comprehensive systematic review and meta-analysis

OBJECTIVE

The alcohol flushing response is common among ethnic East Asian populations, and has been associated with an increased risk in developing esophageal cancer, especially squamous cell esophageal cancer (ESCC). We aimed to quantify the relationship between the facial flushing response to alcohol consumption and ESCC.

METHODS

We conducted a meta-analysis of studies reporting on the association between the facial flushing response to alcohol consumption and ESCC. Pooled odds ratios (OR) and 95% confidence intervals (CI) were calculated using a random effects model for the risk of ESCC associated with the facial flushing response in general, as well for different levels of alcohol consumption. Four databases, Medline, PubMed, Embase, and Current Contents Connect, were searched to 31 August 2015.

RESULTS

Seven studies, with 1014 ESCC cases, met the inclusion criteria. There was a positive relationship between the flushing response and ESCC (OR 1.97; 95% CI 1.25-3.13). Heterogeneity was observed (I(2)= 80%, P<0.001). Publication bias was not present. An increased risk of ESCC was present in the moderate and heavy drinkers who experienced flushing, compared with moderate and heavy drinkers who did not (OR 2.54; 95% CI 1.64-3.91, and OR 2.90; 95% CI 1.82-4.82, respectively).

CONCLUSION

Individuals who experience a facial flushing response to alcohol intake may be at increased risk of developing ESCC, particularly if they are moderate to heavy drinkers.

Consumption of hot beverages and foods and the risk of esophageal cancer: a meta-analysis of observational studies

Background

Previous studies have mostly focused on the effects of specific constituents of beverages and foods on the risk of esophageal cancer (EC). An increasing number of studies are now emerging examining the health consequences of the high temperature of beverages and foods. We conducted a meta-analysis to summarize the evidence and clarify the association between hot beverages and foods consumption and EC risk.

Methods

We searched the PubMed, Embase, and Web of Science databases for relevant studies, published before May 1, 2014, with the aim to estimate the association between hot beverage and food consumption and EC risk. A random-effect model was used to pool the results from the included studies. Publication bias was assessed by using the Begg test, the Egger test, and funnel plot.

Results

Thirty-nine studies satisfied the inclusion criteria, giving a total of 42,475 non-overlapping participants and 13,811 EC cases. Hot beverage and food consumption was significantly associated with EC risk, with an odds ratio (OR) of 1.82 (95% confidence interval [CI], 1.53–2.17). The risk was higher for esophageal squamous cell carcinoma, with a pooled OR of 1.60 (95% CI, 1.29–2.00), and was insignificant for esophageal adenocarcinoma (OR: 0.79; 95% CI: 0.53–1.16). Subgroup analyses suggests that the association between hot beverage and food consumption and EC risk were significant in Asian population (OR: 2.06; 95% CI: 1.62-2.61) and South American population (OR: 1.52; 95% CI: 1.25-1.85), but not significant in European population (OR: 0.95; 95% CI: 0.68-1.34).

Conclusions

Hot beverage and food consumption is associated with a significantly increased risk of EC, especially in Asian and South American populations, indicating the importance in changing people’s dietary habits to prevent EC.

Diet and upper gastrointestinal malignancies

Diet is believed to modulate cancer risk and this relationship has been widely studied in the gastrointestinal tract. Observational epidemiologic studies have provided most of the evidence about the effects of diet on cancer risk because clinical trials to determine nutritional exposures are often impossible, impractical, or unaffordable. Although a few foods or nutrients are thought to protect against specific types of cancer, it seems clear that the strength and even direction of dietary associations (increasing or decreasing risk) is organ-site- and even histology-specific, along the gastrointestinal tract. Although some hypotheses are supported by a substantial body of observational data (drinking hot maté [an infusion of the herb Ilex Paraguarensis] contributes to esophageal cancer), there are not much data to support others. We discuss some highly touted hypotheses and draw interim conclusions about what is known and what could be done to improve the level of evidence. The complex nature of diet and its associations can be productively investigated with disease-specific studies. However, public health recommendations for normal-risk individuals regarding diet and gastrointestinal cancer should probably emphasize the importance of eating for overall health rather than eating specific foods to reduce risk for specific cancers.