Vegetables, fruit, antioxidants and cancer: a review of Italian studies

Summary Background Case-control studies have suggested that a diet rich in fresh fruit and vegetables protects from the risk of most common epithelial cancers, including those of the digestive tract, and also several nondigestive neoplasms; however, selections in cohort studies have been generally weaker. Aim of the study To review the relation between frequency of consumption of vegetables and fruit, estimated intake of selected antioxidants and the risk of cancer at different sites. Methods Systematic overview of data, with specific focus on a network of case-control studies conducted in Italy from 1983 to 1999. Results The relative risks (RR) of digestive tract neoplasms were reduced in subjects reporting highest vegetable intake. A protective effect of vegetables was also observed for hormone-related neoplasms. Fruit was related to a reduced RR of cancers of the upper digestive tract, stomach and urinary tract. With reference to the role of selected antioxidants, beta-carotene, vitamins C and E showed a significant inverse relation with oral and pharyngeal, esophageal and breast cancer risk. Against colorectal cancer, the most consistent protective effects were provided by carotene, riboflavin and vitamin C, but inverse relations were observed also for calcium and vitamin D. Conclusions Fruit and vegetable consumption in Mediterranean populations appears to provide protection against several types of neoplasms. Received: 27 July 2001, Accepted: 23 October 2001     

Diet and oral,pharyngeal, and esophageal cancer

Cancers of the upper digestive tract, including those arising in the oral cavity, pharynx, and esophagus, present a significant public health problem worldwide. These cancers are associated with high morbidity and mortality, and identification of protective factors is very important. A number of epidemiological studies have examined the association between vegetables, fruits, carotene, vitamin A, vitamin C, and vitamin E and oral, pharyngeal, and esophageal cancers. The results of 35 epidemiological studies, including one prospective cohort study, one nested case-control study, two randomized controlled trials, nine population-based case-control studies, and 22 hospital-based case-control studies, in addition to in vitro and animal studies, were examined to determine whether the criteria for causal assumption were satisfied for a protective role of these dietary components against development of oral, pharyngeal, and esophageal cancers. There is enough evidence to point to a preventive role of vegetable intake, including green vegetables, cruciferous vegetables, and yellow vegetables, total fruit intake, and citrus fruit intake. Yellow fruits are likely to be protective. Carotene, vitamin C, and vitamin E are protective, most likely in combination with each other and other micronutrients. The role of vitamin A is not clear because of conflicting findings in the studies reviewed.     

Vegetables, Fruits, and Legumes: Effect on Urinary Isoflavonoid Phytoestrogen and Lignan Excretion

Objective To compare the effect of vegetable, fruit, and legume consumption on urinary isoflavonoid phytoestrogen and lignan excretion.Design After 4 days of data collection, during which subjects consumed their habitual diets, subjects were randomly placed on four 9-day controlled experimental diets with each subject receiving each diet in a random order.Subjects Seven men and three women, aged 20 to 35 years, were recruited from the University of Minnesota Twin Cities community.Interventions All subjects consumed four experimental diets in an assigned random order: a controlled basal diet, a legume/allium diet (containing garbanzo beans, garlic, and onions), and diets low or high in vegetables and fruits (containing apples, pears, potatoes, and carrots).Main outcome measures Urine samples that were collected while subjects consumed their habitual diets and during the last 3 days of each feeding period were analyzed for isoflavonoid and lignan content using isotope dilution gas chromatography-mass spectrometry.Statistical analysis performed The effect of vegetable and fruit intake on urinary isoflavonoid and lignan excretion was analyzed using the general linear model procedure. Post hoc comparisons were made using Duncan's multiple range test.Results Subjects excreted more of the lignan enterodiol on the high vegetable/fruit diet compared with the basal and legume/allium diets (P=.03); more of the isoflavonoids O-desmethylangolensin (O-DMA), genistein, and sum of isoflavonoids on the legume/allium diet compared with the other controlled diets (P<.05); and more of the isollavan equol on the basal and legume/allium diets compared with the high vegetable/fruit diet (P<.01). Subjects who excreted higher levels of equol on the basal and legume/allium diets also consumed more of the milk-based pudding provided as part of the controlled diets.Conclusions Urinary lignan and isoflavonoid excretion changed in response to alterations in vegetable, fruit, and legume intake under controlled dietary conditions. J Am Diet Assoc. 1995; 95:769-774.     

Dealing with variability in food production chains: a tool to enhance the sensitivity of epidemiological studies on phytochemicals

Summary. Background: Many epidemiological studies have tried to associate the intake of certain food products with a reduced risk for certain diseases. Results of these studies are often ambiguous, conflicting, or show very large deviations of trends. Nevertheless, a clear and often reproduced inverse association is observed between total vegetable and fruit consumption and cancer risk. Examples of components that have been indicated to have a potential protective effect in food and vegetables include antioxidants, allium compounds and glucosinolates. Aim: The food production chain can give a considerable variation in the level of bioactive components in the products that are consumed. In this paper the effects of this variability in levels of phytochemicals in food products on the sensitivity of epidemiological studies are assessed. Methods: Information on the effect of variation in different steps of the food production chain of Brassica vegetables on their glucosinolate content is used to estimate the distributions in the levels in the final product that is consumed. Monte Carlo simulations of an epidemiological cohort study with 30,000 people have been used to assess the likelihood of finding significant associations between food product intake and reduced cancer risk. Results: By using the Monte Carlo simulation approach, it was shown that if information on the way of preparation of the products by the consumer was quantified, the statistical power of the study could at least be doubled. The statistical power could be increased by at least a factor of five if all variation of the food production chain could be accounted for. Conclusions: Variability in the level of protective components arising from the complete food production chain can be a major disturbing factor in the identification of associations between food intake and reduced risk for cancer. Monte Carlo simulation of the effect of the food production chain on epidemiological cohort studies has identified possible improvements in the set up of such studies. The actual effectiveness of food compounds already identified as cancer-protective by current imprecise methods is likely to be much greater than estimated at present. Received: 15 July 2002, Accepted: 26 January 2003 Correspondence to: Matthijs Dekker     

Meat Consumption and Risk of Lung Cancer Among Never-Smoking Women

The relationship between diet and lung cancer, apart from the protective effect of fruit and vegetables, is poorly understood. Reports on the role of dietary components such as meat are inconsistent, and few studies include sufficient numbers of nonsmokers. We examined the relationship between meat consumption and never-smoking lung cancer in a hospital-based case–control study of Singapore Chinese women, a population with low smoking prevalence. Three hundred and ninety-nine cases and 815 controls were recruited, of whom 258 cases and 712 controls were never smokers. A standardized questionnaire (which included a food frequency questionnaire module) was administered by trained interviewers. Among these never smokers, fruit and vegetable intake were inversely associated with lung cancer risk. Seventy-two percent of meat consumed was white meat (chicken or fish). Meat consumption overall was inversely associated with lung cancer [adjusted odds ratio (OR), 0.88, 0.59 for second, third tertiles, P _trend = .012]. An inverse relationship between fish consumption and lung cancer (adjusted OR, 0.81, 0.47 for 2nd, 3rd tertiles, P _trend < .001) was observed. No association was seen between consumption of processed meats and lung cancer, nor between dietary heterocyclic amines and lung cancer. Our data suggest that fish consumption may be protective against lung cancer in never smokers.     

Knowledge, barriers, and stage of change as correlates of fruit and vegetable consumption among urban and mostly immigrant black men

BACKGROUND: Daily fruit and vegetable consumption in black men is low and has remained relatively unchanged during the past 20 years. OBJECTIVE: To examine awareness of fruit and vegetable recommendations promoted by federal agencies and correlates of fruit and vegetable consumption among an urban and mostly immigrant population of adult black men. DESIGN: A cross-sectional study analyzing baseline data (n=490) from a randomized controlled trial. SETTING: A large health care worker's union. MAIN OUTCOME MEASURES: Knowledge, perceived benefits, stage of readiness, perceived barriers, and daily servings of fruit and vegetable intake. STATISTICAL ANALYSES PERFORMED: One-way analysis of variance and t tests were used to compare fruit and vegetable intake across main study variables. Regression analysis was used to identify independent predictors of fruit and vegetable intake. RESULTS: Fruit and vegetable intake was low (mean was three servings/day). Ninety-four percent were not aware that men should consume at least nine servings of fruits and vegetables daily and 59.8% were not aware that eating a colorful variety is important. In contrast, over half (54.7%) were aware that a single serving is equal to about a handful; 94.1% correctly reported fruit and vegetables as an important source of fiber; 79.6% correctly reported vitamin pills were not a substitute for eating fruits and vegetables; and 94.5% recognized that there are health benefits to eating fruits and vegetables, although identification of specific benefits was minimal. In regression analysis, a greater level of fruit and vegetable consumption was significantly associated with greater knowledge of fruit and vegetable recommendations, lower perceived barriers, and a more advanced stage of change (action vs contemplation/preparation). Perceived health benefits were not associated with fruit and vegetable consumption. CONCLUSIONS: There is a lack of awareness of the current fruit and vegetable recommendations. In addition, men reported fruit and vegetable intakes that were far below national recommendations. Greater efforts are needed to help urban and primarily immigrant black men realize the importance of and recommendations for fruit and vegetable consumption.     

Antioxidant vitamins and risk of gastric cancer: a case-control study in Portugal

We quantified the effect of antioxidant vitamins in gastric cancer risk, taking into account Helicobacter pylori seropositivity and overall fruit and vegetable intake. Incident cases were identified in two large hospitals in Porto, Portugal, and controls were randomly sampled among city dwellers. Food intake was assessed with a previously validated semiquantitative food-frequency questionnaire. A commercially available chromatographic immunoassay was used for the detection of immunoglobulin G antibodies. Complete questionnaire information and serum samples were available for 233 cases and 311 controls. Compared with subjects in the lowest tertile of dietary intake, the odds ratios (ORs) for those in the highest were 0.85 (95% confidence interval, CI = 0.45-1.60) for vitamin C, 1.04 (95% CI = 0.60-1.80) for vitamin E, and 1.33 (95% CI = 0.77-2.30) for provitamin A carotenoids after further adjusting for fruit and vegetable consumption. Fruit and vegetables remained an independent protective factor (OR = 0.45; 95% CI = 0.23-0.89) after further adjustment for the intake of antioxidant vitamins. H. pylori status had no significant interaction with dietary items. Factors other than H. pylori infection and intake of vitamin C and provitamin A carotenoids seem to account for the inverse association between fruit and vegetable consumption and gastric cancer.     

Intake of Fruits,Vegetables, and Soy Foods in Relation to Breast Cancer Risk in Korean Women: A Case-Control Study

We conducted a case-control study to examine the relationship between fruit, vegetable, and soy food intake and breast cancer risk in Korean women. Incident cases (n = 359) were identified through cancer biopsies between March 1999 and August 2003 at two university hospitals in Seoul, Korea. Hospital-based controls (n = 708) were selected from patients in the same hospitals during the same period. Subjects were asked by personal interview to indicate their average fruit, vegetable, and soy food intake for a 12-mo period 3 yr prior to the baseline phase. A food intake–frequency questionnaire (98 items) was given by a trained dietitian. Odds ratio (OR) and 95% confidence intervals (CIs) were calculated by unconditional logistic regression after adjustment for confounding factors and total energy intake. There was no association between the intake of total fruits, vegetables, or soy food and breast cancer risk. Increasing consumption of grapes was linked to a significant protective effect against risk of breast cancer (OR = 0.66; 95% CI = 0.41–0.86; P < 0.01). Among the vegetables, reduced risk was observed with high tomato intake (OR = 0.62; 95% CI = 0.38–0.81; P < 0.01). Among soy foods, high consumption of cooked soybeans, including yellow and black soybeans, had an association with reduced breast cancer (OR = 0.67; 95% CI = 0.45–0.91; P < 0.02). Our data suggest that increased intake of some fruits, vegetables, and soy foods may be associated with breast cancer risk reduction in Korean women.     

Vegetable and fruit consumption and risks of colon and rectal cancer in a prospective cohort study: The Netherlands Cohort Study on Diet and Cancer

The relation between vegetable and fruit consumption and colorectal cancer risk was comprehensively assessed in the Netherlands Cohort Study on Diet and Cancer using a validated 150-item food frequency questionnaire. After 6.3 years of follow-up (1986-1992), over 1,000 incident cases of colorectal cancer were registered. Using case-cohort analysis, the authors calculated rate ratios and 95% confidence intervals adjusted for age, alcohol intake, and family history of colorectal cancer. For colon cancer, no statistically significant associations with total vegetable intake or total fruit intake were found. However, among women, an inverse association was observed with vegetables and fruits combined (for the highest quintile vs. the lowest, the rate ratio was 0.66 (95% confidence interval: 0.44, 1.01)). Brassica vegetables and cooked leafy vegetables showed inverse associations for both men and women. Among women and, to a lesser extent, among men, inverse associations were stronger for distal colonic tumors than for proximal colonic tumors. For rectal cancer, no statistically significant associations were found for vegetable consumption or fruit consumption or for specific groups of vegetables and fruits; only Brassica vegetables showed a positive association in women. As in other cohort studies, the observed inverse relation between vegetable and fruit consumption and occurrence of colorectal cancer was less strong than relations reported in case-control studies.     

Diet and cancer of the esophagus

The reported dietary, alcohol consumption and smoking habits of 147 Roswell Park Memorial Institute white male patients diagnosed with cancer of the esophagus were compared with the reports of 264 white males of comparable ages with diagnoses other than cancer. Overall frequency of vegetable and fruit consumption was associated with lower risk; persons reporting fruit and/or vegetable consumption 31–40 times a month had significantly greater risk than those who reported consumption 81 times a month or more. Calculated indexes of vitamin A and vitamin C intake were similarly related to reduction in risk. Dose‐response gradients were observed for frequency of vegetable and/or fruit consumption, as well as for vitamin A and C intake. The putative protective effect of vegetable and fruit intake remained evident after controlling for its possible association with smoking and drinking. Previously reported associations of smoking, alcohol use and social class, as measured by type of occupation, were replicated in these data. The findings of this investigation are consistent with evidence of lower risk associated with vege‐”; table consumption in instances of colon, lung, bladder, oral, and laryngeal cancers, and with evidence of tumor inhibition by vegetable properties in animals. Interpretation of the findings is limited by the difficulties of retrospective assessment of dietary intake and by possible confounding by other factors known to be related to esophageal cancer.     

Association between fruit and vegetable consumption and oral cancer: a meta-analysis of observational studies

BACKGROUND: Oral cancer ranks as the seventh most common form of cancer worldwide. Recent reports have examined the effect of fruit and vegetable intake on the risk of oral cancer, but results are controversial. OBJECTIVE: A meta-analysis was performed to arrive at quantitative conclusions about the contribution of fruit and vegetable intakes to the occurrence of oral cancer. DESIGN: A comprehensive, systematic bibliographic search of medical literature published up to September 2005 was conducted to identify relevant studies. Separate meta-analyses were conducted for fruit and vegetable consumption. The effect of portion or daily intake of fruit or vegetables on the risk of oral cancer was calculated. A multivariate meta-regression analysis was performed to explore heterogeneity. This multivariate meta-regression analysis examined the effect of quality score, the type of cancers included, citrus fruit and green vegetable consumption, and the time interval for dietary recall of the studies on the role of fruit or vegetable consumption in the risk of oral cancer. The presence of publication bias was assessed with a funnel plot for asymmetry. RESULTS: Sixteen studies (15 case-control studies and 1 cohort study) met the inclusion criteria and were included in the meta-analysis. The combined adjusted odds ratio (OR) estimates showed that each portion of fruit consumed per day significantly reduced the risk of oral cancer by 49% (OR: 0.51; 95% CI: 0.40, 0.65). For vegetable consumption, the meta-analysis showed a significant reduction in the overall risk of oral cancer of 50% (OR: 0.50; 95% CI: 0.38, 0.65). The multivariate meta-regression showed that the lower risk of oral cancer associated with fruit consumption was significantly influenced by the type of fruit consumed and by the time interval of dietary recall. CONCLUSION: The consumption of fruit and vegetables is associated with a reduced risk of oral cancer.     

Foodstuffs and colorectal cancer risk: a review

BACKGROUND AND AIMS: To assess the relationships between food intake and colorectal cancer risk. METHODS: Systematic review of available prospective studies on dietary intake and colorectal cancer. RESULTS: Twelve out of 15 studies found no significant relationship between vegetable intake and colorectal cancer risk; also, 11 out of 14 studies found no relationship with fruit consumption. Conversely, the combined consumption of vegetables and fruit reduced colorectal cancer risk in three out of six studies, although the relationship was somewhat inconsistent between genders and anatomical localizations. Most studies found no relationship between cancer risk and red meat (15 in 20) or processed meat (seven out of 11) consumption; still, most of the reported relative risks were above unity, suggesting that high consumption of red or processed meat might increase colorectal cancer risk. The consumption of white meat, fish/seafood, dairy products, coffee or tea was mostly unrelated to colorectal cancer risk, although the consumption of smoked or salted fish actually increased risk. CONCLUSIONS: The relationships between dietary intake and colorectal cancer risk might be less important than previously reported. The combined consumption of vegetables and fruit might be protective, whereas excessive consumption of meat or smoked/salted/processed food appears to be deleterious.     

Intake of fruits, vegetables, and soy foods in relation to breast cancer risk in Korean women: a case-control study

We conducted a case-control study to examine the relationship between fruit, vegetable, and soy food intake and breast cancer risk in Korean women. Incident cases (n=359) were identified through cancer biopsies between March 1999 and August 2003 at two university hospitals in Seoul, Korea. Hospital-based controls (n=708) were selected from patients in the same hospitals during the same period. Subjects were asked by personal interview to indicate their average fruit, vegetable, and soy food intake for a 12-mo period 3 yr prior to the baseline phase. A food intake-frequency questionnaire (98 items) was given by a trained dietitian. Odds ratio (OR) and 95% confidence intervals (CIs) were calculated by unconditional logistic regression after adjustment for confounding factors and total energy intake. There was no association between the intake of total fruits, vegetables, or soy food and breast cancer risk. Increasing consumption of grapes was linked to a significant protective effect against risk of breast cancer (OR=0.66; 95% CI=0.41-0.86; P<0.01). Among the vegetables, reduced risk was observed with high tomato intake (OR=0.62; 95% CI=0.38-0.81; P<0.01). Among soy foods, high consumption of cooked soybeans, including yellow and black soybeans, had an association with reduced breast cancer (OR=0.67; 95% CI=0.45-0.91; P<0.02). Our data suggest that increased intake of some fruits, vegetables, and soy foods may be associated with breast cancer risk reduction in Korean women.     

Fruit, vegetables, and cancer prevention: a review of the epidemiological evidence.

Approximately 200 studies that examined the relationship between fruit and vegetable intake and cancers of the lung, colon, breast, cervix, esophagus, oral cavity, stomach, bladder, pancreas, and ovary are reviewed. A statistically significant protective effect of fruit and vegetable consumption was found in 128 of 156 dietary studies in which results were expressed in terms of relative risk. For most cancer sites, persons with low fruit and vegetable intake (at least the lower one-fourth of the population) experience about twice the risk of cancer compared with those with high intake, even after control for potentially confounding factors. For lung cancer, significant protection was found in 24 of 25 studies after control for smoking in most instances. Fruits, in particular, were significantly protective in cancers of the esophagus, oral cavity, and larynx, for which 28 of 29 studies were significant. Strong evidence of a protective effect of fruit and vegetable consumption was seen in cancers of the pancreas and stomach (26 of 30 studies), as well as in colorectal and bladder cancers (23 of 38 studies). For cancers of the cervix, ovary, and endometrium, a significant protective effect was shown in 11 of 13 studies, and for breast cancer a protective effect was found to be strong and consistent in a meta analysis. It would appear that major public health benefits could be achieved by substantially increasing consumption of these foods.     

Fruit and vegetable consumption,ethnicity and risk of fatal ischemic heart disease

Objective: Mortality rates from ischemic heart disease vary among ethnic groups. Dietary intake of fruits and vegetables has been associated with a lower risk of ischemic heart disease, but ethnic-specific data are limited. Design: Prospective cohort study. Setting: Hawaii and Los Angeles County, between 1993 and 1996. Participants: These analyses included 164,617 adults age 45 to 75, representing five ethnic groups who were enrolled in the Multiethnic Cohort Study. Dietary data were collected at baseline using a validated food frequency questionnaire and fatal ischemic heart disease cases were identified up to December 31, 2001. Associations between fruit and vegetable consumption and fatal ischemic heart disease were examined using multivariate Cox proportional hazard models. Results: The associations between fruit and vegetable intake and fatal ischemic heart disease were similar among the five ethnic groups. When data for the ethnic groups were combined, higher vegetable intake was associated with a protective effect against ischemic heart disease in men with all intake levels above 3.4 servings per day (over 6.6 servings per day: hazard ratio, 0.73; 95% confidence interval, 0.58–0.92). Inconsistent results were observed for women, where the protective association was observed only at mid-level vegetable intake levels, but not among women with the highest level of vegetable intake. There was no evidence of an association for fruit intake. Conclusions: Associations between fruit and vegetable intake and fatal IHD do not appear to vary among ethnic groups. Additional research is needed to clarify associations for fruit versus vegetable intake and impact on cardiovascular outcomes.     

Plasma carotenoid levels in Dutch men and women, and the relation with vegetable and fruit consumption

OBJECTIVE: Fruit and vegetable intake is inversely associated with cancer risk in many epidemiological studies. Accurate assessment of consumption of these foods is difficult, and biomarkers of intake would overcome several drawbacks of currently used dietary assessment methods. Therefore, we investigated the relation between plasma carotenoids and usual vegetable and fruit intake. DESIGN: Plasma carotenoid concentrations were measured and vegetable, fruit and juice consumption was assessed by a food frequency questionnaire (FFQ) in a random sample of 591 Dutch men and women aged 20-59 y from the MORGEN-project, one of the contributions to the European Prospective Investigation into Cancer and Nutrition (EPIC)-study. RESULTS: In this sample of the general Dutch population, in both genders, relative to the other carotenoids, plasma beta-cryptoxanthin was the best indicator for fruit intake, and for the sum of vegetable, fruit and juice intake, while lutein concentrations best reflected intake of vegetables, although quartiles of intake were not consistently separated. Since levels of lycopene were not associated with any of the main food groups examined, associations with total carotenoids improved when excluding lycopene, and monotonously increasing plasma levels were seen for intakes of vegetables, of fruits, and of the sum of vegetables, fruits and juices. Several vegetable types and orange/grapefruit juice were associated with plasma levels of one of the carotenoids. CONCLUSION: Plasma carotenoids were only crude indicators of vegetable and fruit intake as assessed by a FFQ; beta-cryptoxanthin for fruit intake and lutein for vegetable intake. None of the plasma carotenoids could distinguish all four quartiles of vegetables, fruit and/or juice intake.     

Fruit and vegetables in cancer prevention

Our aim was to review the epidemiological literature on possible cancer-preventive effects of the consumption of fruits and vegetables in humans, to quantify the effect of high versus low consumption of fruits and vegetables, and to give an overall assessment of the existing evidence. We based our work on an expert meeting conducted by the International Agency for Research on Cancer in 2003. A qualitative reading and evaluation of relevant articles on the cancer-preventive effect of the consumption of fruits and vegetables was made followed by the calculation of the mean relative risk and range for cohort and case-control studies separately. The possible population-preventable fraction for modifying diet in relation to fruit and vegetable consumption was calculated as well as an overall statement about the degree of evidence for the cancer-preventive effect of fruit and vegetable consumption for each cancer site. There is limited evidence for a cancer-preventive effect of the consumption of fruits and vegetables for cancer of the mouth and pharynx, esophagus, stomach, colon-rectum, larynx, lung, ovary (vegetables only), bladder (fruit only), and kidney. There is inadequate evidence for a cancer-preventive effect of the consumption of fruits and vegetables for all other sites. Applying this range of risk difference to the range of prevalence of low intake, the preventable fraction for low fruit and vegetable intake would fall into the range of 5-12%. It is important to recognize that this is only a crude range of estimates and that the proportion of cancers that might be preventable by increasing fruit and vegetable intake may vary beyond this range for specific cancer sites and across different regions of the world.     

Vegetables, fruits, and related nutrients and risk of breast cancer: a case-control study in Uruguay

To evaluate whether the protective effect associated with vegetables and fruits in breast cancer could be explained by nutrients and bioactive substances present in these plant foods, we carried out a case-control study in Uruguay including 400 cases and 405 controls. The intake of vegetables, fruits, and related nutrients was estimated with a food frequency questionnaire on 64 food items. This questionnaire allowed the calculation of total energy intake, and nutrients were calorie adjusted by the residuals method. Odds ratios for study variables were estimated by unconditional multiple logistic regression. Total vegetable, total fruit, dietary fiber, vitamin C, vitamin E, lycopene, folate, and total phytosterol intakes were inversely associated with breast cancer risk [4th quartile odds ratio for total vegetable intake = 0.41, 95% confidence interval = 0.26-0.65, p (for trend) = 0.004]. The association with total vegetable intake was not independent of lycopene intake. The results related to vegetable and nutrient intakes are consistent with antioxidant and antiestrogenic effects. This could be mediated, among other nutrients, by dietary fiber and lycopene intake. The role of other unmeasured phytochemicals, correlated with dietary fiber and lycopene intakes, cannot be ruled out.     

Fruit,Vegetable, and Animal Food Intake and Breast Cancer Risk by Hormone Receptor Status

The effects of diet on breast cancer are controversial and whether the effects vary with hormone receptor status has not been well investigated. This study evaluated the associations of dietary factors with risk for breast cancer overall and by the hormone receptor status of tumors among Chinese women. The Shanghai Breast Cancer Study, a large, population-based, case-control study, enrolled 3,443 cases and 3,474 controls in 1996–1998 (phase I) and 2002–2005 (phase II); 2676 cases had estrogen receptor (ER) and progesterone receptor (PR) data. Dietary intake was assessed using a validated, quantitative, food frequency questionnaire. Odds ratios (OR) and 95% confidence intervals (95% CI) were derived from multivariate, polychotomous, unconditional logistic regression models. Total vegetable intake was inversely related to breast cancer risk, with an adjusted OR for the highest quintile of 0.80 (95% CI = 0.67–0.95; P trend = 0.02). Reduced risk was also related to high intake of allium vegetables (P trend = 0.01) and fresh legumes (P trend = 0.0008). High intake of citrus fruits and rosaceae fruits were inversely associated with breast cancer risk (P trend = 0.003 and 0.004, respectively), although no consistent association was seen for total fruit intake. Elevated risk was observed for all types of meat and fish intake (all P trend < 0.05), whereas intakes of eggs and milk were associated with a decreased risk of breast cancer (both P trend <0.05). There was little evidence that associations with dietary intakes varied across the 4 tumor subtypes or between ER+/PR+ and ER-/PR- tumors (P for heterogeneity >0.05). Our results suggest that high intake of total vegetables, certain fruits, milk, and eggs may reduce the risk of breast cancer, whereas high consumption of animal-source foods may increase risk. The dietary associations did not appear to vary by ER/PR status.     

Gastric Cancer and Allium Vegetable Intake: A Critical Review of the Experimental and Epidemiologic Evidence

There are suggestions of an anticancerogenic effect of allium vegetables and their associated organosulfur components against several cancer types, including gastric cancer, but the issue remains open to discussion and quantification. The present critical review discussed the history, the health properties, the chemistry, the anticancerogenic evidences from experimental studies, and the anticancer mechanisms of allium vegetables. We also summarized findings from epidemiological studies concerning the association between different types of allium vegetables and gastric cancer risk, published up to date. Available data, derived mainly from case-control studies, suggested a favorable role of high intakes of allium vegetables, mainly garlic and onion, in the etiology of gastric cancer. In particular, of 10 studies, 7 suggested a favorable role of high intake of total allium vegetables and gastric cancer. All 14 studies on garlic and most studies on onion (more than 80%) reported a beneficial role of these allium types against gastric cancer. However several limitations, including possible publication bias and the difficulty to establish a dose-risk relationship, suggest caution in the interpretation. Evidences on other types of allium vegetables, as well as on the influence of different gastric cancer anatomical and histological types, are less consistent.