References 51 to 100
In conclusion, it seems reasonable to hypothesize that AITC, and possibly other ITCs, may find use in the treatment of human prostate cancers.
CONCLUSIONS: The inverse association between intake of fruits and vegetables and the risk of cancer of the colon, breast, and stomach has generally been much stronger in case-control than in cohort studies. We have no clear explanation for this.
CONCLUSIONS: These results indicate that consumption of a wide variety of vegetables has a greater bearing on lung cancer risk in a population of smoking and nonsmoking women than intake of any specific carotenoid or total carotenoids.
Our study suggests that high intake of certain vegetables and fruits may be associated with a reduced risk of breast cancer.
This report provides evidence that plant foods have an important preventive influence in a population at high risk for lung cancer. However, persons who use beta-carotene supplements do not benefit from the protective compounds in plant foods.
These results support the evidence that daily consumption of fruit and vegetables reduces the risk of total cancer, and specifically cancers of the stomach, liver, and lung.
CONCLUSIONS: Childhood fruit consumption may have a long term protective effect on cancer risk in adults. Further prospective studies, with individual measures of diet are required to further elucidate these relations.
The reduced risk of prostate cancer associated with allium vegetables was independent of body size, intake of other foods, and total calorie intake and was more pronounced for men with localized than with advanced prostate cancer.
CONCLUSIONS: Our results suggest that dietary intake of antioxidants measured as total antioxidant potential is inversely associated with risk of both cardia and distal cancer. The innovative approach used in this study provides a new tool for investigating the relationship between dietary antioxidants and oxidative stress-related carcinogenesis.
This prospective study suggests that vegetable and fruit intake, even in low amounts, is associated with a lower risk of gastric cancer. Although no striking differences in the association were seen between cardia and noncardia cancer, an inverse association was higher in differentiated rather than in undifferentiated types of gastric cancer.
Results clearly point toward a positive correlation between cancer prevention of many target organs and consumption of cruciferous vegetable or their active constituents. Yet we are still far from complete understanding of the effects of combinations of chemopreventive phytochemicals present in these cruciferous vegetables and their overall mechanism(s) of action in providing protective effects.
Because elevated vegetable consumption has been associated with a lower risk of colorectal cancer, vegetables may have a stronger role in preventing the progression of adenomas to carcinomas rather than in preventing the initial appearance of adenomas.
Thus, studies in animal models and in cell-culture systems have furnished a lot of information about the potential mechanism by which a diet high in fruits and vegetables may reduce the risk of cancer in humans. However, more investigation in the identification of the biologically active constituents, in the knowledge of their availability and the mechanism by which they contribute to lower the risk of cancer, will increase the scientific support of a public health policy.
CONCLUSIONS: Fruit and vegetable consumption in Mediterranean populations appears to provide protection against several types of neoplasms.
The data are suggestive of an inverse association between the consumption of brassicas, total fruit, and urothelial cancer risk, whereas total vegetable consumption did not appear to be associated with urothelial cancer risk.
Antiproliferative activity has been described in several tumor cell lines, which is possibly mediated by induction of apoptosis and alterations of the cell cycle. Allium vegetables and organosulfur compounds are thus possible cancer-preventive agents. Clinical trials will be required to define the effective dose that has no toxicity in humans.
CONCLUSIONS: Individuals who consume very low amounts of fruit and vegetables have the greatest risk of colorectal cancer. Relatively high consumption of cereal fiber does not appear to lower the risk of colorectal cancer.
These results suggest that legumes (not limited to soy products) and certain categories of vegetables may protect against prostate cancer.
These substances act in a variety of different ways--for example carotinoids and flavonoids inhibit carcinogen-activating enzymes, phyto-estrogens and indoles have a modulating effect on the hormone metabolism, while saponins or sulfides stimulate the body's natural killer cells. Against this background, the German Society for Nutrition (Deutsche Gesellschaft fur Ernahrung) recommends the daily consumption of 375 grams of vegetables and about 250 to 300 grams of fruit.
CONCLUSIONS: Increasing consumption of fruits and vegetables carries a large public health potential. Population trials and biological mechanisms should eventually provide scientific proof of their efficacy. The available evidence is sufficient to justify public health education and promotion aimed at a substantial increase in the consumption of fruits and vegetables.
CONCLUSIONS: Diets high in fresh fruit and salad vegetables appear protective against cancer and Cardio Vascular Disease. It is important to take into account the seasonality of consumption in estimating and establishing significance of risk.
Most evidence concerning anticarcinogenic effects of glucosinolate hydrolysis products and brassica vegetables has come from studies in animals. In addition, studies carried out in humans using high but still realistic human consumption levels of indoles and brassica vegetables have shown putative positive effects on health. The combination of epidemiological and experimental data provide suggestive evidence for a cancer preventive effect of a high intake of brassica vegetables.
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.
The results of the survey suggest that frequent consumption of allium vegetables, in addition to other anticancer foods, may be a factor in low mortality for gastric cancer.
The main results in the present study suggested that allium vegetables, like raw vegetables, may have an important protecting effect against not only stomach cancer, but also esophageal cancer.
These results establish that humans convert substantial amounts of isothiocyanates and glucosinolates to urinary dithiocarbamates that can be easily quantified, thus paving the way for meaningful studies of phase 2 enzyme induction in humans.
It has been calculated that a 65% increase of the intake of vegetables and fruits will reduce the incidence of cancer by about 23% or about 4,000 cases in Norway every year. It is also estimated that recommended diets, together with maintenance of physical activity and appropriate body mass, can reduce cancer incidence by 30-40%.
Preliminary results are suggestive of a positive association of DNA damage with beef and pork intake and a negative association with cooked vegetable intake. APPLICATION: These observations, if confirmed in larger studies, suggest specific dietary changes to reduce oxidative DNA damage levels and possibly cancer risk.
Most vegetables were inversely associated with cancer of the colon and rectum, whereas only carrots and raw vegetables lowered breast cancer risk. High fruit intake was associated only with a reduction of rectal cancer. Different contents of sugar, fiber, carotenoids, and folic acid in fruits vs vegetables plus the concurrent consumption of oil with vegetables may partly explain these findings.
Controlling for potentially confounding factors, the relative risk among subjects with the lowest compared to those with the highest intake was 5.5 (95% CI 1.7-18.3) with a statistically significant dose-risk trend (p < 0.05). Our results indicate that information bias is not likely to explain the discrepancy between the results of observational studies and of randomized-intervention trials.
Thus, from a public health viewpoint, epidemiological evidence indicates that a substantial reduction in epithelial cancer risk can be obtained by increasing fruit and vegetable consumption.
Current US vegetable and fruit intake, which averages about 3.4 servings per day, is discussed, as are possible noncancer-related effects of increased vegetable and fruit consumption, including benefits against cardiovascular disease, diabetes, stroke, obesity, diverticulosis, and cataracts. Suggestions for dietitians to use in counseling persons toward increasing vegetable and fruit intake are presented.
This association appears to be most consistent for lung, stomach, colon, and rectal cancer and least consistent for prostatic, endometrial, and ovarian cancer. It is not yet possible to resolve whether associations are to be attributed to brassica vegetables per se or to vegetables in general. Further epidemiological research should separate the anticarcinogenic effect of brassica vegetables from the effect of vegetables in general.
CONCLUSIONS: In this population, intake of vegetables appears to decrease premenopausal breast cancer risk. This effect may be related, in part, to beta-carotene and lutein + zeaxanthin in vegetables. It appears, however, that, of the nutrients and food components examined, no single dietary factor explains the effect. Evaluated components found together in vegetables may have a synergistic effect on breast cancer risk; alternatively, other unmeasured factors in these foods may also influence risk.
After adjustment for potential confounders (which included body mass index, total energy, and total alcohol intake), a reduction in risk for total vegetable intake, total fruit intake, and lettuce, apple, and banana consumption was observed. The strongest protection was observed for banana intake (odds ratio 0.28; 95% confidence level 0.16-0.50) for consumption in the third tertile compared with the first.
These isoprenoids also suppress tumor growth. The HMG-CoA reductase of neoplastic tissues differs from that of sterologenic tissues in being markedly resistant to sterol feedback inhibition. Our review suggests that the mevalonate pathway of tumor tissues is uniquely sensitive to the inhibitory actions of the dietary isoprenoids.
Consumption of garlic was inversely associated with risk, with an age- and energy-adjusted relative risk of 0.68 (95% confidence interval (CI) 0.46-1.02) for the uppermost versus the lowermost consumption levels. Inverse associations were also observed for intakes of all vegetables and dietary fiber; age- and energy-adjusted relative risks for the uppermost versus the lowermost intake quartiles were 0.73 (95% CI 0.47-1.13) and 0.80 (95% CI 0.49-1.31), respectively. Associations for the other vegetable and fruit groups were less remarkable.
The risk of lung cancer among current smokers declined markedly with increasing intake of lettuce and cabbage. A similar effect was observed among ex-smokers and non-smokers, but there was no statistical significance. In the multivariate analysis, fruit and raw vegetables showed the strongest protective effects against lung cancer among current smokers (P = 0.01). Among ex-smokers, the protective effect of fruit is also statistically significant (P = 0.03). These results suggest that fruit and raw vegetables may play an important role in protecting smokers from lung cancer.
Vegetable consumption was associated with risk of all histologic types of lung cancer, but the pattern of increasing risk with decreasing intake was limited to smokers. We infer that consumption of yellow/green vegetables and carotenoids may confer protection from lung cancer to White male and White female smokers. Further studies are needed to clarify the effect in Blacks.
The mechanisms of anticarcinogenic substances in fruits and vegetables are discussed in the light of cancer prevention and inhibition.
This is the first study to demonstrate a protective effect of vegetable intake versus the strong effects of smoking and occupational exposures on lung cancer risk.
This is the first case control study to show an association between pickled vegetable consumption and oesophageal cancer risk. The finding considerably strengthens the evidence for carcinogenicity of N-nitroso compounds in man and helps to explain the very high risk among Chinese.
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.
One way to consider the relationships reviewed here is to hypothesize that humans are adapted to a high intake of plant foods that supply substances crucial to the maintenance of the organism, but only some of which are currently called 'essential nutrients.' Cancer may be the result of reducing the level of intake of foods that are metabolically necessary--it may be a disease of maladaptation.