***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: The effect of multivariate adjustment including folate on the strong protective effect of fiber in foods on colorectal cancer risk in the European Prospect i ve Investigation into Cancer and Nutrition was investigated in 1,721 cases identified in the latest follow-up . The inclusion of an additional 656 cases confirmed our previously published results , with a strong and significant reduction in colorectal cancer risk of ∼9 % for each uncalibrated quintile increase in fiber ( Plinear trend < 0.001 ) compared with an 8 % reduction in our previous report , which had not been adjusted for folate . Inclusion of the other covariates ( physical activity , alcohol , smoking , and red and processed meat ) confirmed this significant inverse association for colon cancer and strengthened the association with left-sided colon cancer ( P < 0.001 ) . After maximum adjustment , the association between fiber and rectal cancer was not significant , as in our previous analysis . The association with fiber from different food sources was analyzed , but again , there were no significance trends after maximum adjustment BACKGROUND The hypothesis that increased intake of dietary fibre lowers the risk of colorectal cancer ( CRC ) has recently been weakened by results from cohort and intervention studies that did not detect such an association . We investigated the association between  dietary fibre intake  and risk of CRC in a cohort of women that prospect ively answered a food frequency question naire ( FFQ ) . METHODS We studied 45 491 women in the Breast Cancer Detection Demonstration Project ( BCDDP ) follow-up cohort . A 62-item FFQ was administered from 1987 and 1989 to assess dietary intake . Participants received follow-up question naires ( in 1992 - 1995 and 1995 - 1998 ) on which they reported incident cancers . Cases were also identified through search es of the National Death Index and state cancer registries . Cox proportional hazard regression was used to generate risk ratios and 95 % CI for quintiles of total fibre intake and fibre subtypes . RESULTS During a mean follow-up time of 8.5 years we identified 487 colorectal cancer cases . The 10th and 90th percentiles of dietary fibre intake were 5.4 g and 18.2 g respectively . For total fibre we observed no association with colorectal cancer ( fifth versus first quintile , RR = 0.94 , 95 % CI : 0.71 - 1.23 ) . Analyses by subgroup of fibre and by anatomical subsite did not reveal any stronger inverse associations . CONCLUSIONS Within a cohort of older women characterized by a relatively low fibre intake , there was little evidence that dietary fibre intake lowers the risk of colorectal cancer We examined prospect ively the association between whole grain consumption and  colorectal cancer risk  in the population -based Swedish Mammography Cohort . A total of 61 433 women completed a food-frequency question naire at baseline ( 1987–1990 ) and , through linkage with the Swedish Cancer Registry , 805 incident cases of colorectal cancer were identified during a mean follow-up of 14.8 years . High consumption of whole grains was associated with a lower risk of colon cancer , but not of rectal cancer . The multivariate rate ratio ( RR ) of colon cancer for the top category of whole grain consumption ( ⩾4.5 servings day−1 ) compared with the bottom category ( < 1.5 servings day−1 ) was 0.67 ( 95 % confidence interval ( CI ) , 0.47–0.96 ; P-value for trend=0.06 ) . The corresponding RR after excluding cases occurring within the first 2 years of follow-up was 0.65 ( 95 % CI , 0.45–0.94 ; P-value for trend=0.04 ) . Our findings suggest that high consumption of whole grains  may decrease the risk of colon cancer in women BACKGROUND Limited scientific evidence has characterized the association between dietary fiber intake and risk of breast cancer ( BC )  by menopausal status and hormone receptor expression in tumors . OBJECTIVE We investigated the relation between  total dietary fiber  and its main food sources ( vegetables , fruit , cereals , and legumes ) and BC risk by using data from the European Prospect i ve Investigation into Cancer and Nutrition ( EPIC ) . DESIGN A total of 11,576 invasive BC cases in 334,849 EPIC women mostly aged 35 - 70 y at baseline were identified over a median follow-up of 11.5 y.  Dietary fiber  was estimated from country-specific dietary question naires . Multivariable Cox proportional hazards regression models were used to quantify the association between dietary variables and BC risk with energy adjustment by using the residual method . Subgroup analyses were performed by menopausal status and estrogen receptor ( ER ) and progesterone receptor ( PR ) expression in tumors . RESULTS BC risk was inversely associated with intakes of  total dietary fiber  [ hazard ratio comparing fifth quintile to first quintile ( HR(Q5-Q1 ) ) : 0.95 ; 95 % CI : 0.89 , 1.01 ; P-trend = 0.03 ] and fiber from vegetables ( 0.90 ; 0.84 , 0.96 ; P-trend < 0.01 ) but not with fiber from fruit , cereals , or legumes . Overall , associations were homogeneous by menopausal status and ER and PR expression in tumors . For vegetable fiber , stronger associations were observed for estrogen receptor-negative and progesterone receptor-negative ( HR(Q5-Q1):0.74 ; 95 % CI : 0.59 , 0.93 ; P-trend = 0.01 ) than for estrogen receptor-positive and progesterone receptor-positive tumors ( 0.92 : 0.81 , 1.03 ; P-trend = 0.05 ) , with P-heterogeneity = 0.09 . CONCLUSION Diets rich in dietary fiber and , particularly , fiber from vegetables may be associated with a small reduction in risk of BC , independently of menopausal status BACKGROUND Although the Mediterranean diet has been studied for cancer mortality and the Dietary Approaches to Stop Hypertension ( DASH ) diet shares similarities with the Mediterranean diet , few studies have specifically examined these 2 diets and incident colorectal cancer . OBJECTIVE The objective was to prospect ively assess the association between the Alternate Mediterranean Diet ( aMed ) and the DASH-style diet scores and risk of colorectal cancer in middle-aged men and women . DESIGN A total of 87,256 women and 45,490 men ( age 30 - 55 y for women and 40 - 75 y for men at baseline ) without a history of cancer were followed for ≤ 26 y.  The aMed and DASH scores  were calculated for each participant by using dietary information that was assessed ≤ 7 times during follow-up . Relative risks ( RRs ) for colorectal cancer were computed with adjustment for potential confounders . RESULTS We documented 1432 cases of incident colorectal cancer among women and 1032 cases in men . Comparing top with bottom quintiles of the DASH score , the pooled RR for total colorectal cancer was 0.80 ( 95 % CI : 0.70 , 0.91 ; P for trend = 0.0001 ) . The corresponding RR for DASH score and colon cancer was 0.81 ( 95 % CI : 0.69 , 0.95 ; P for trend = 0.002 ) . There was a suggestion of an inverse association with rectal cancer with a pooled RR of 0.73 ( 95 % CI : 0.55 , 0.98 ; P for trend = 0.31 ) when comparing top with bottom quintiles of DASH score . No association was observed with aMed  score . CONCLUSION Adherence to the DASH diet ( which involves higher intakes of whole grains , fruit , and vegetables ; moderate amounts of low-fat dairy ; and lower amounts of red or processed meats , desserts , and sweetened beverages ) was associated with a lower risk of colorectal cancer Objective : To assess the relation between whole and refined grain intake and risk of incident postmenopausal breast cancer .  Findings from case – control studies of whole and refined grain intake and risk of postmenopausal breast cancer have been inconclusive . Methods : The Iowa Women 's Health Study is a prospect i ve cohort study of women initially 55–69 years old that relates diet and other lifestyle factors to cancer risk . After exclusions a total of 29,119 menopausal women who answered a 1986 baseline and a 1989 follow-up question naire were followed for 9 years for incident breast cancer . Results : Compared to women who at baseline rarely ate whole grain foods , women who habitually ate whole grain had a healthier lifestyle , including a higher likelihood of prior screening mammography . The multivariate-adjusted risk of incident breast cancer was 20 % higher in women in the highest quintile of whole grain intake , compared to women in the lowest quintile of whole grain intake ( 95 % confidence interval 0.95–1.5 ; p-value for trend = 0.03 ) . No increase in breast cancer risk was found in women who had not undergone screening mammography  before 1989 ; the apparent increase in risk was therefore likely due to increased use of screening mammography . Refined grain intake was not associated with breast cancer risk . Conclusion : Consistent with inverse but not statistically significant associations between whole grain intake and breast cancer in case – control studies , both whole and refined grain intakes are unrelated to risk of postmenopausal breast cancer in these Iowa women Objective : Although animal studies suggest an inverse association between consumption of plant foods and risk of colorectal cancer , many observational data have failed to support such an association . We prospect ively examined the association between  dietary intakes of fruit , vegetables , and fiber and colorectal cancer risk in a large female cohort from the Women ’s Health Study . Methods : Among 39,876 healthy women aged ≥45 years at baseline , 36,976 with baseline self-reported information on dietary intakes and other risk factors for colorectal cancer were included in the analyses . During an average follow-up of 10 years , 223 women were diagnosed with colorectal cancer .  Intakes of fruit , vegetables , and fiber were assessed by a baseline food-frequency question naire . The analyses were carried out using the Cox proportional hazards regression and all tests were two-sided . Results : Intakes of fruit , vegetables , and the specific subgroups were not found to be associated with colorectal cancer risk . Multivariate relative risks ( RRs ) comparing the highest with lowest quintile were 0.79 ( 95 % CI = 0.49–1.27,pfor trend = 0.30 ) for fruit intake , and 0.88 ( 95 % CI=0.56–1.38,pfor trend=0.30 ) for vegetables intake . Similarly , intake of total fiber was not associated with colorectal cancer risk ; the RR for the highest relative to lowest quintile was 0.75 ( 95 % CI=0.48–1.17,pfor trend=0.12 ) . However , higher intake of legume fiber was associated with a lower risk of colorectal cancer ; the RR for the highestversuslowest quintile was 0.60 ( 95 % CI=0.40–0.91,pfor trend=0.02 ) . Conclusions : Our data offer little support for associations between intakes of  fruit , vegetables , and fiber , and colorectal cancer risk . However , our data suggest that legume fiber and /or other related sources may reduce risk of colorectal cancer Background : Consumption of wholegrain ( WG ) products may protect against colon and rectal cancer . Methods : The associations between total and individual WG product consumption and colon and rectal cancer risk were prospect ively examined using data on 461 incident cases of colon cancer and 283 incident cases of rectal cancer that developed during 10.6 years ( median ) of follow-up among 26 630 men and 29 189 women taking part in the Diet , Cancer and Health cohort .  Incidence rate ratios ( IRRs ) of colon and rectal cancer related to total or individual WG product intake were calculated using Cox regression . Results : Higher WG product intake was associated with lower risk of colon cancer and rectal cancer in men . The adjusted IRR ( 95 % CI ) was 0.85 ( 0.77–0.94 ) for colon cancer and 0.90 ( 0.80–1.01 ) for rectal cancer per daily 50 g increment in intake . For colon cancer the association was confined to intake of WG bread in particular . No consistent associations between total or individual WG product consumption and colon or rectal cancer risk were observed in women . Conclusion : The findings suggest that higher total WG product intake is associated with a lower risk of colon and  perhaps rectal cancer in men , but not in women Numerous case-control studies suggest dietary fiber may reduce risk of gastric cancer , but this has not been confirmed prospect ively . A previous case-control study reported reduced risk of gastric cardia adenocarcinomas associated with cereal fiber , but not with fruit or vegetable fiber . To date , different food sources of fiber have 
    Output:
    
This systematic review concludes that most studies were suggestive of a null association .