Mediterranean diet and colorectal cancer risk: results from a European cohort

Effectiveness of interventions applicable to primary health care settings to promote Mediterranean diet or healthy eating adherence in adults: A systematic review

OBJECTIVE

To evaluate the effects on healthy eating or the Mediterranean diet adherence achieved by interventions suitable for implementation in primary care settings.

METHODS

Medline (PubMed) and The Cochrane Library bibliographic searches retrieved randomized controlled trials published in English or Spanish, January 1990-January 2013. The inclusion criteria were adult population, >3 months follow-up, and interventions suitable for primary care settings. Exclusion resulted if studies focused exclusively on weight loss or did not analyze food intake (fats, fruits and vegetables--F&V, fiber) or Mediterranean diet adherence. Validity (risk of bias) was independently evaluated by two researchers; discrepancies were reviewed until a consensus was reached.

RESULTS

Of the 15 included articles (14 studies), only 3 studies surpassed 12-months follow-up. Ten interventions emphasized healthy nutrition (n = 9948); 4 added activity levels (n = 3816). Six trials included participants with cardiovascular risk; 7 were community-based; 1 focused on women with cancer. Eleven studies showed 9.7% to 59.3% increased F&V intake with counseling interventions, compared to baseline (-13.3% to 27.8% in controls). Seven studies reported significant differences between intervention and control groups.

CONCLUSION

Nutritional counseling moderately improves nutrition, increases intake of fiber, F&V, reduces dietary saturated fats, and increases physical activity. Studies with longer follow-up are needed to determine long-term effects, cardiovascular morbidity, and mortality.

Epigenetics could explain some Moroccan population colorectal cancers peculiarities: microsatellite instability pathway exploration

Background

Colorectal Cancers (CRC) are one of the most common malignancies in the world. Their incidence in Morocco, between 2005 and 2007, was 5.6 for 100000 inhabitants, which is very low compared to what found in developed countries. In addition, CRCs show a high frequency of rectal localizations, and occurs in a younger population in Morocco compared to what found in developed countries.

The purpose of this study is to confirm these CRC peculiarities in Morocco and try to explain them by exploring the microsatellite instability molecular pathway.

Methods

This is a prospective observational study conducted since January 2010, including 385 patients admitted in Hassan II University Hospital of Fez. We collected clinical, radiological and pathological data. We investigated the expression of mismatch repair (MMR) proteins in 214 patients and BRAF gene mutations in 159 patients.

Results

Mean age was 55.08 +/− 15.16 years. 36.5 % of patients were less than 50 years old and 49.3 % of tumors were localized in the rectum. Loss of MMR protein expression was observed in 11.2 % of cases. It was independently associated with individual or family history of cancer belonging to Hereditary Non-Polyposis Colorectal Cancer (HNPCC) spectrum (p = 0.01) and proximal localization (p = 0.02). No BRAF mutation was detected in all cases.

Conclusions

These results confirm the high occurrence of CRCs to young patients and the high frequency of rectal localizations in Moroccan population. They mostly show an absence of BRAF mutation, supposing a rarity of MLH1 promoter hypermethylation pathway, which may even partially explain the CRC peculiarities in our context.

Virtual Slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/5868184711716884

Vegetarian dietary patterns and the risk of colorectal cancers

IMPORTANCE

Colorectal cancers are a leading cause of cancer mortality, and their primary prevention by diet is highly desirable. The relationship of vegetarian dietary patterns to colorectal cancer risk is not well established.

OBJECTIVE

To evaluate the association between vegetarian dietary patterns and incident colorectal cancers.

DESIGN, SETTING, AND PARTICIPANTS

The Adventist Health Study 2 (AHS-2) is a large, prospective, North American cohort trial including 96,354 Seventh-Day Adventist men and women recruited between January 1, 2002, and December 31, 2007. Follow-up varied by state and was indicated by the cancer registry linkage dates. Of these participants, an analytic sample of 77,659 remained after exclusions. Analysis was conducted using Cox proportional hazards regression, controlling for important demographic and lifestyle confounders. The analysis was conducted between June 1, 2014, and October 20, 2014.

EXPOSURES

Diet was assessed at baseline by a validated quantitative food frequency questionnaire and categorized into 4 vegetarian dietary patterns (vegan, lacto-ovo vegetarian, pescovegetarian, and semivegetarian) and a nonvegetarian dietary pattern.

MAIN OUTCOMES AND MEASURES

The relationship between dietary patterns and incident cancers of the colon and rectum; colorectal cancer cases were identified primarily by state cancer registry linkages.

RESULTS

During a mean follow-up of 7.3 years, 380 cases of colon cancer and 110 cases of rectal cancer were documented. The adjusted hazard ratios (HRs) in all vegetarians combined vs nonvegetarians were 0.78 (95% CI, 0.64-0.95) for all colorectal cancers, 0.81 (95% CI, 0.65-1.00) for colon cancer, and 0.71 (95% CI, 0.47-1.06) for rectal cancer. The adjusted HR for colorectal cancer in vegans was 0.84 (95% CI, 0.59-1.19); in lacto-ovo vegetarians, 0.82 (95% CI, 0.65-1.02); in pescovegetarians, 0.57 (95% CI, 0.40-0.82); and in semivegetarians, 0.92 (95% CI, 0.62-1.37) compared with nonvegetarians. Effect estimates were similar for men and women and for black and nonblack individuals.

CONCLUSIONS AND RELEVANCE

Vegetarian diets are associated with an overall lower incidence of colorectal cancers. Pescovegetarians in particular have a much lower risk compared with nonvegetarians. If such associations are causal, they may be important for primary prevention of colorectal cancers.

Microbial mucosal colonic shifts associated with the development of colorectal cancer reveal the presence of different bacterial and archaeal biomarkers

BACKGROUND

Epidemiological studies demonstrate a link between gastrointestinal cancers and environmental factors such as diet. It has been suggested that environmental cancer risk is determined by the interaction between diet and microbes. Thus, the purpose of this study was to examine the hypothesis that microbiota composition during colorectal cancer (CRC) progression might differ depending on the stage of the disease.

METHODS

A total of 28 age-matched and sex-matched subjects, seven with CRC adenocarcinoma, 11 with tubular adenomas and ten healthy subjects with intact colon, were included into the study. Microbiomes from mucosal and fecal samples were analyzed with 16S ribosomal RNA gene pyrosequencing, together with quantitative PCR of specific bacteria and archaea.

RESULTS

The principal coordinates analysis clearly separated healthy tissue samples from polyps and tumors, supporting the presence of specific bacterial consortia that are associated with affected sites and that can serve as potential biomarkers of CRC progression. A higher presence of Fusobacterium nucleatum and Enterobacteriaceae was found by qPCR in samples from CRC compared to healthy controls. We observed a correlation between CRC process development and levels of Methanobacteriales (R = 0.537, P = 0.007) and Methanobrevibacterium (R = 0.574, P = 0.03) in fecal samples.

CONCLUSION

Differences in microbial and archaeal composition between mucosal samples from healthy and disease tissues were observed in tubular adenoma and adenocarcinoma. In addition, microbiota from mucosal samples represented the underlying dysbiosis, whereas fecal samples seem not to be appropriate to detect shifts in microbial composition. CRC risk is influenced by microbial composition, showing differences according to disease progression step and tumor severity.

Diet and colorectal cancer

BACKGROUND

Colorectal cancer (CRC) is the third most common diagnosed cancer in men and the second in women. Dietary factors and lifestyle may contribute to the increasing CRC incidence, making these issues interesting for both the general population and the medical oncology community.

OBJECTIVE

The aim of this report is to present a review of the published epidemiologic research to date reflecting the most current scientific evidence related to diet and CRC risk.

DESIGN

EMBASE and PubMed-NCBI were searched for relevant articles up to November 2014 that identified potential interactions between foods or dietary patterns and CRC risk.

RESULTS

Obesity increases the risk of CRC by 19%. Regular physical activity reduces this risk by 24%. CRC risk derived from red meat intake is influenced by both total intake and its frequency. Fish consumption may decrease CRC risk by 12% whereas garlic intake is not significantly associated with reduced CRC risk. Intakes of more than 20g/day of fiber are associated with a 25% reduction of CRC risk and 525mL/day of milk reduces colon cancer risk by 26% in men. Moderate amounts of alcohol (25-30g/day) increase CRC risk.

CONCLUSIONS

CRC is a preventable disease through the modification of associated risk factors, including physical inactivity, obesity and overweight, excessive meat intake, smoking and alcoholic beverage consumption. Nonetheless, epidemiological evidence in this regard is not conclusive so further research is warranted.

Paleolithic and Mediterranean diet pattern scores and risk of incident, sporadic colorectal adenomas

The Western dietary pattern is associated with higher risk of colorectal neoplasms. Evolutionary discordance could explain this association. We investigated associations of scores for 2 proposed diet patterns, the "Paleolithic" and the Mediterranean, with incident, sporadic colorectal adenomas in a case-control study of colorectal polyps conducted in Minnesota (1991-1994). Persons with no prior history of colorectal neoplasms completed comprehensive questionnaires prior to elective, outpatient endoscopy; of these individuals, 564 were identified as cases and 1,202 as endoscopy-negative controls. An additional group of community controls frequency-matched on age and sex (n = 535) was also recruited. Both diet scores were calculated for each participant and categorized into quintiles, and associations were estimated using unconditional logistic regression. The multivariable-adjusted odds ratios comparing persons in the highest quintiles of the Paleolithic and Mediterranean diet scores relative to the lowest quintiles were, respectively, 0.71 (95% confidence interval (CI): 0.50, 1.02; Ptrend = 0.02) and 0.74 (95% CI: 0.54, 1.03; Ptrend = 0.05) when comparing cases with endoscopy-negative controls and 0.84 (95% CI: 0.56, 1.26; Ptrend = 0.14) and 0.77 (95% CI: 0.53, 1.11; Ptrend = 0.13) when comparing cases with community controls. These findings suggest that greater adherence to the Paleolithic diet pattern and greater adherence to the Mediterranean diet pattern may be similarly associated with lower risk of incident, sporadic colorectal adenomas.

Mediterranean diet and health status: an updated meta-analysis and a proposal for a literature-based adherence score

OBJECTIVE

To update previous meta-analyses of cohort studies that investigated the association between the Mediterranean diet and health status and to utilize data coming from all of the cohort studies for proposing a literature-based adherence score to the Mediterranean diet.

DESIGN

We conducted a comprehensive literature search through all electronic databases up to June 2013.

SETTING

Cohort prospective studies investigating adherence to the Mediterranean diet and health outcomes. Cut-off values of food groups used to compute the adherence score were obtained.

SUBJECTS

The updated search was performed in an overall population of 4 172 412 subjects, with eighteen recent studies that were not present in the previous meta-analyses.

RESULTS

A 2-point increase in adherence score to the Mediterranean diet was reported to determine an 8 % reduction of overall mortality (relative risk = 0·92; 95 % CI 0·91, 0·93), a 10 % reduced risk of CVD (relative risk = 0·90; 95 % CI 0·87, 0·92) and a 4 % reduction of neoplastic disease (relative risk = 0·96; 95 % CI 0·95, 0·97). We utilized data coming from all cohort studies available in the literature for proposing a literature-based adherence score. Such a score ranges from 0 (minimal adherence) to 18 (maximal adherence) points and includes three different categories of consumption for each food group composing the Mediterranean diet.

CONCLUSIONS

The Mediterranean diet was found to be a healthy dietary pattern in terms of morbidity and mortality. By using data from the cohort studies we proposed a literature-based adherence score that can represent an easy tool for the estimation of adherence to the Mediterranean diet also at the individual level.

The role of a Mediterranean diet on the risk of oral and pharyngeal cancer

BACKGROUND

The Mediterranean diet has a beneficial role on various neoplasms, but data are scanty on oral cavity and pharyngeal (OCP) cancer.

METHODS

We analysed data from a case-control study carried out between 1997 and 2009 in Italy and Switzerland, including 768 incident, histologically confirmed OCP cancer cases and 2078 hospital controls. Adherence to the Mediterranean diet was measured using the Mediterranean Diet Score (MDS) based on the major characteristics of the Mediterranean diet, and two other scores, the Mediterranean Dietary Pattern Adherence Index (MDP) and the Mediterranean Adequacy Index (MAI).

RESULTS

We estimated the odds ratios (ORs), and the corresponding 95% confidence intervals (CI), for increasing levels of the scores (i.e., increasing adherence) using multiple logistic regression models. We found a reduced risk of OCP cancer for increasing levels of the MDS, the ORs for subjects with six or more MDS components compared with two or less being 0.20 (95% CI 0.14-0.28, P-value for trend <0.0001). The ORs for the highest vs the lowest quintile were 0.20 (95% CI 0.14-0.28) for the MDP score (score 66.2 or more vs less than 57.9), and 0.48 (95% CI 0.33-0.69) for the MAI score (score value 2.1 or more vs value less 0.92), with significant trends of decreasing risk for both scores. The favourable effect of the Mediterranean diet was apparently stronger in younger subjects, in those with a higher level of education, and in ex-smokers, although it was observed in other strata as well.

CONCLUSIONS

Our study provides strong evidence of a beneficial role of the Mediterranean diet on OCP cancer.

Definitions and potential health benefits of the Mediterranean diet: views from experts around the world

The Mediterranean diet has been linked to a number of health benefits, including reduced mortality risk and lower incidence of cardiovascular disease. Definitions of the Mediterranean diet vary across some settings, and scores are increasingly being employed to define Mediterranean diet adherence in epidemiological studies. Some components of the Mediterranean diet overlap with other healthy dietary patterns, whereas other aspects are unique to the Mediterranean diet. In this forum article, we asked clinicians and researchers with an interest in the effect of diet on health to describe what constitutes a Mediterranean diet in different geographical settings, and how we can study the health benefits of this dietary pattern.

Do statins increase and Mediterranean diet decrease the risk of breast cancer?

BACKGROUND

Physical exercise and healthy dietary habits are recommended to prevent breast cancer.

DISCUSSION

Increased intake of omega-3 fatty acids associated with decreased omega-6 - resulting in higher omega-3 to omega-6 ratio compared with Western-type diet - is inversely associated with breast cancer risk. The modernized Mediterranean diet with high omega-3 to omega-6 ratio, high fiber and polyphenol intake, and consumption of low-glycemic index foods reduces overall cancer risk and specifically breast cancer risk. It has been suggested that consuming no more than one alcoholic drink per day, preferably wine, is preferable. Eliminating environmental contaminants, including endocrine disruptors, and favoring organic foods to increase polyphenol intake and the omega-3 to omega-6 ratios were also shown to be beneficial. Cholesterol-lowering statins may decrease antitumor defenses; are toxic for the mitochondria; decrease the omega-3 to omega-6 ratio; increase body mass index, insulin resistance and diabetic risk; and have been associated with an increased breast cancer risk.

SUMMARY

Therefore, as well as making lifestyle changes to decrease breast cancer risk, we argue that physicians should carefully consider (and often avoid) therapies that may increase breast cancer or diabetes risk in high-risk women and women who wish to decrease their breast cancer risk.

Circulating immune cell activation and diet: A review on human trials

Protein energy malnutrition is the main cause of immunodeficiency and, secondarily, of several infections. However, immune cell activation is involved in several pathophysiological processes that play a crucial role in the appearance of cardiovascular disease (CVD) or cancer. The aim of this review is to update the knowledge of the modulation of immune cell activation by different dietary patterns and its components focusing on CVD or cancer. While a westernized high-saturated fat high-carbohydrate diet is positively associated with low-grade inflammation, vegetable- and fruit-based diets rich in monounsaturated fatty acids, polyunsaturated fatty acids and polyphenols, key nutrients of Mediterranean diet, decrease the levels of cellular and circulating inflammatory biomarkers thereby reducing the risk of related chronic diseases.

Adherence to Mediterranean diet and risk of cancer: a systematic review and meta-analysis of observational studies

The aim of this research study was to meta-analyze the effects of adherence to Mediterranean diet (MD) on overall cancer risk, and different cancer types. Literature search was performed using the electronic databases MEDLINE, SCOPUS and EMBASE until January 10, 2014. Inclusion criteria were cohort or case-control studies. Study specific risk ratios (RRs) were pooled using a random effect model by the Cochrane software package Review Manager 5.2. Twenty-one cohort studies including 1,368,736 subjects and 12 case-control studies with 62,725 subjects met the objectives and were enclosed for meta-analyses. The highest adherence to MD category resulted in a significantly risk reduction for overall cancer mortality/incidence (cohort; RR: 0.90, 95% CI 0.86-0.95, p < 0.0001; I(2) = 55%), colorectal (cohort/case-control; RR: 0.86, 95% CI 0.80-0.93, p < 0.0001; I(2) = 62%], prostate (cohort/case-control; RR: 0.96, 95% CI 0.92-0.99, p = 0.03; I(2) = 0%) and aerodigestive cancer (cohort/case-control; RR: 0.44, 95% CI 0.26-0.77, p = 0.003; I(2) = 83%). Nonsignificant changes could be observed for breast cancer, gastric cancer and pancreatic cancer. The Egger regression tests provided limited evidence of substantial publication bias. High adherence to a MD is associated with a significant reduction in the risk of overall cancer mortality (10%), colorectal cancer (14%), prostate cancer (4%) and aerodigestive cancer (56%).

Polydatin, a natural precursor of resveratrol, induces cell cycle arrest and differentiation of human colorectal Caco-2 cell

Background

Human colon adenocarcinoma cells are resistant to chemotherapeutic agents, such as anthracyclines, that induce death by increasing the reactive oxygen species. A number of studies have been focused on chemo-preventive use of resveratrol as antioxidant against cardiovascular diseases, aging and cancer. While resveratrol cytotoxic action was due to its pro-oxidant properties. In this study, we investigate whether the Resveratrol (trans-3,5,49-trihydroxystilbene) and its natural precursor Polydatin (resveratrol-3-O-b-mono- D-glucoside, the glycoside form of resveratrol) combination, might have a cooperative antitumor effect on either growing or differentiated human adenocarcinoma colon cancer cells.

Methods

The polydatin and resveratrol pharmacological interaction was evaluated in vitro on growing and differentiated Caco-2 cell lines by median drug effect analysis calculating a combination index with CalcuSyn software. We have selected a synergistic combination and we have evaluated its effect on the biological and molecular mechanisms of cell death.

Results

Simultaneous exposure to polydatin and resveratrol produced synergistic antiproliferative effects compared with single compound treatment. We demonstrated that polydatin alone or in combination with resveratrol at 3:1 molar ratio synergistically modulated oxidative stress, cell cycle, differentiation and apoptosis. Worthy of note treatment with polydatin induced a nuclear localization and decreased expression of heat shock protein 27, and vimentin redistributed within the cell.

Conclusions

From morphological, and biochemical outcome we obtained evidences that polydatin induced a transition from a proliferative morphology to cell-specific differentiated structures and caused human CaCo-2 cell death by induction of apoptosis. Our data suggest the potential use of polydatin in combination chemotherapy for human colon cancer.

The role of Mediterranean diet on the risk of pancreatic cancer

Background:

The Mediterranean diet has been shown to have a beneficial role on various neoplasms, but data are scanty on pancreatic cancer.

Methods:

We analysed data from two case–control studies conducted in Italy between 1983 and 2008, including 362 and 326 pancreatic cancer cases and 1552 and 652 hospital-controls, respectively. A Mediterranean Diet Score (MDS) summarising major characteristics of the Mediterranean diet was used in the two studies separately and overall. Two further scores of adherence to the Mediterranean diet were applied in the second study only, the Mediterranean Dietary Pattern Adherence Index (MDP) and the Mediterranean Adequacy Index (MAI).

Results:

Odds ratios (ORs) for increasing levels of the scores (i.e., increasing adherence) were estimated using multiple logistic regression models. Odds ratio for a MDS score ⩾6 compared with <3 was 0.57 (95% confidence interval (CI) 0.34–0.95) in the first study, 0.51 (95% CI 0.29–0.92) in the second study, and 0.48 (95% CI 0.35–0.67) overall. A trend of decreasing risk was observed also for the MDP and MAI the ORs for the highest vs the lowest quintile being 0.44 (95% CI 0.27–0.73) for MDP and 0.68 (95% CI 0.42–1.11) for the MAI. The results were consistent across strata of age, sex, education, body mass index, alcohol drinking, tobacco smoking, and diabetes.

Conclusion:

Our study provides evidence that a priori-defined scores measuring adherence to the Mediterranean diet are favourably associated with pancreatic cancer risk.