Dietary fiber intake and risk of postmenopausal breast cancer defined by estrogen and progesterone receptor status—A prospective cohort study among Swedish women

Abstract

There is few data on the association between dietary fiber intake and estrogen receptor (ER)/progesterone receptor (PR)-defined breast cancer risk. We evaluated the association between dietary fiber and ER/PR-defined breast cancer risk stratified by postmenopausal hormone use, alcohol intake, and family history of breast cancer in the population-based Swedish Mammography Screening Cohort comprising 51,823 postmenopausal women. Fiber intake was measured by food-frequency questionnaire collected in 1987 and 1997. Relative risks (RRs) were estimated by hazard ratio derived from Cox proportional hazard regression models. During an average of 8.3-year follow-up, 1,188 breast cancer cases with known ER/PR status were diagnosed. When comparing the highest to the lowest quintile, we observed non-significant inverse associations between total fiber intake and the risk of all tumor subtypes; the multivariate-adjusted RRs were 0.85 (95% CI: 0.69-1.05) for overall, 0.85 (0.64-1.13) for ER1PR1, 0.83 (0.52-1.31) for ER1PR2 and 0.94 (0.49-1.80) for ER2PR2. For specific fiber, we observed statistically significant risk reductions for overall (34%) and for ER1PR1 (38%) for the highest versus lowest quintile of fruit fiber, and non-significant inverse associations for other subtypes of cancer and types of fiber. Among ever-users of postmenopausal hormone (PMH), total fiber intake and especially cereal fiber were statistically significantly associated with 50% reduced risk for overall and ER1PR1 tumors when comparing the highest to the lowest quartile, but no association was observed among PMH never users. Our results suggest that dietary fiber intake from fruit and cereal may play a role in reducing breast cancer risk. ' 2007 Wiley-Liss, Inc.Key words: breast cancer; estrogen receptor; progesterone receptor; dietary fiber; risk Breast cancer is the most prevalent malignancy among women in Western countries. A number of studies indicate that a high level of endogenous/exogenous steroid hormones may play a critical role in the development of postmenopausal breast cancer. 1-4 It has been postulated that dietary fiber intake may reduce estrogen levels through interference of fiber with their enterohepatic metabolism. 5 Proposed mechanisms include increasing fecal excretion of estrogens, inhibition of intestinal reabsorption of estrogens by suppressing bacterial b-glucuronidase activity or binding unconjugated estrogens to fiber in the colon. 6-10 It has been also reported an association of increased dietary fiber intake and fiber-related phytochemicals with a reduction of estrogen levels in blood 6,[11][12][13] and with increased level of sex hormone-binding globulin (SHBG), which binds estradiol affecting its bioavailability. [14][15][16] Thus, it has been hypothesized that fiber intake may be associated with a decreased risk of breast cancer through the reduction of circulating estrogen levels. 17 Moreover, fiber might also indirectly reduce the risk of postmenopausal breast cancer by preventing obesity and type 2 diabetes-both bei...

Dietary lignans and postmenopausal breast cancer risk by oestrogen receptor status: a prospective cohort study of Swedish women

“…There was no evidence of heterogeneity across ER/PR tumours. These results are similar to our previous study with a significant inverse association between cereal fibre and breast cancer risk among PMH users (Suzuki et al, 2008). The estimated lignan intake was correlated with cereal fibre (r ¼ 0.7) but after adjusting for specific fibres, the association among PMH users was still significant.…”

Dietary Carbohydrate, Fiber and Sugar and Risk of Breast Cancer According to Menopausal Status in Malaysia

“…Consistently, the NIH-AARP Diet and Health Study found that dietary fiber intake in the highest quintiles can lower postmenopausal breast cancer risk by 13% (RR=0.87; 95%CI: 0.77-0.98) (Park et al, 2009). Although our study findings were supported by two prospective studies, several other studies failed to establish that a diet with low dietary fiber has harmful effects towards breast cancer risk among postmenopausal women (Holmes et al, 2004;Giles et al, 2006;Cade et al, 2007;Suzuki et al, 2008;Wen et al, 2009;Shikany et al, 2011;Zaineddin et al, 2012;Ferrari et al, 2013).…”

“…Concurrently, there have been striking changes in mortality rates of breast cancer among other cancers which lagged around 10 years from the beginning of the nutrition transition towards a westernized diet in selected geographical location in East Asia (Zhang et al, 2012). In the past decade, dietary carbohydrate, fiber and sugar has gained much attention in relation towards breast cancer risk according to menopausal status, but studies have been limited in developed countries (Cho et al, 2003;Holmes et al, 2004;Romieu et al, 2004;Mattisson et al, 2004;Nielsen et al, 2005;Giles et al, 2006;Cade et al, 2007;Lajous et al, 2008;Suzuki et al, 2008;Larsson et al, 2009;Wen et al, 2009;Park et al, 2009;Shikany et al, 2011;Zaineddin et al, 2012;Ferrari et al, 2013;Li et al, 2013;Woo et al, 2013). A few studies have appeared from South-East Asia and Eastern Europe (Kruk and Marchlewicz, 2013;Sangrajrang et al, 2013).…”

Dietary Fiber Intake in Young Adults and Breast Cancer Risk

“…[3][4][5] In most prospective studies, [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] including the Nurses' Health Study, 23 no significant associations have been seen between fiber intake and BC risk. In a recent meta-analysis of 16 prospective studies, a weak inverse association was found; for an increment of 10 g fiber per day, a 5% lower BC risk was seen.…”