Phyto-oestrogens and colorectal cancer risk: a systematic review and dose–response meta-analysis of observational studies

Abstract

Epidemiological studies suggest that soya consumption as a source of phyto-oestrogens and isoflavones may be associated with a reduced risk of colorectal cancer. However, findings have not yet been synthesised for all groups of phyto-oestrogens. A meta-analysis was conducted to quantify the association between phyto-oestrogens and colorectal cancer risk. Relevant observational studies published up to June 2016 were identified by searching MEDLINE, EMBASE and Cochrane Library databases. Study-specific relative risks (RR) were pooled in both categorical and dose-response meta-analyses. Out of seventeen identified studies, sixteen were included in the meta-analysis. Comparing the highest with the lowest intake category, inverse associations for phyto-oestrogens overall and by subgroup were observed but were statistically significant in case-controls studies and not in cohort studies. The pooled RR in case-control studies were 0·76 (95 % CI 0·69, 0·84), 0·77 (95 % CI 0·69, 0·85) and 0·70 (95 % CI 0·56, 0·89) for phyto-oestrogens, isoflavones and lignans, respectively, whereas the corresponding pooled RR were 0·95 (95 % CI 0·85, 1·06), 0·94 (95 % CI 0·84, 1·05) and 1·00 (95 % CI 0·64, 1·57) in cohort studies. Dose-response analysis yielded an 8 % reduced risk of colorectal neoplasms for every 20 mg/d increase in isoflavones intake in Asians (pooled RR 0·92; 95 % CI 0·86, 0·97). A non-linear inverse association with colorectal cancer risk was found for lignans intake, but no association for circulating enterolactone concentrations was observed. Thus, study heterogeneity precludes a rigorous conclusion regarding an effect of high exposure to isoflavones on risk of colorectal cancer. Current evidence for an association with lignans exposure is limited. Further prospective studies, particularly evaluating lignans, are warranted to clarify the association between different phyto-oestrogens and colorectal cancer risk.

Prediagnosis plasma concentrations of enterolactone and survival after colorectal cancer: the Danish Diet, Cancer and Health cohort

“…Analyses by tumour subsite and UICC stage of the association between prediagnosis enterolactone concentrations as continuous (per doubling) and all-cause mortalitywomen and men diagnosed with colorectal cancer from the Diet, Cancer and Health cohort* (Numbers, hazard ratios (HR) and 95 % confidence intervals) selection bias similar to the so-called obesity paradox (39) . However, it may not be a major concern in the present study, because no strong association between enterolactone concentrations and colorectal cancer risk has been found in prospective studies (14) .…”

“…In a previous study based on the present cohort, we have found prior antibiotics use to mostly affect enterolactone levels in women (16) and higher enterolactone levels to be associated with lower risk of colorectal cancer among women, but with a higher risk among men (15) . Overall in other cohort studies, no association between enterolactone and risk of colorectal cancer has been found (14,40) . To the best of our knowledge, enterolactone and survival after colorectal cancer has not previously been studied.…”

“…In Asia, isoflavonoids from, for example, soya Abbreviations: DCCG, Danish Colorectal Cancer Group; ER, oestrogen receptor; HR, hazard ratio; UICC, Union for International Cancer Control. products remain the most studied, and a high intake has been related to lower colorectal cancer risk in Asian populations (14) . A previous study based on the same cohort as the present study found enterolactone, the main microbial-derived metabolite of plant lignans, to be associated with lower colorectal cancer incidence among women, but with a higher risk among men (15) .…”

“…A previous study based on the same cohort as the present study found enterolactone, the main microbial-derived metabolite of plant lignans, to be associated with lower colorectal cancer incidence among women, but with a higher risk among men (15) . A recent meta-analysis, which investigated the association between enterolactone concentration, plant lignan intake and colorectal cancer risk (14) found no significant associations. However, the results were based on only four cohort studies.…”

Az ösztrogének lehetséges szerepe a vastagbéldaganatok kialakulásában

“…A szójában is megtalálható fitoösztrogének olyan növényi eredetű vegyületek, amelyek szerkezeti felépítése hasonlít az endogén ösztrogénhez, képesek az ER-okhoz kötődni, különösen az ERβ-hoz, és ezáltal az ERβ által mediált kedvező biológiai választ válthatnak ki. A fitoösztrogének az ER-hoz kötődve transzkripciós szinten szabályozhatják a sejtosztódást, az apoptózist, az angiogenezist vagy a sejtkapcsolatokat szabályozó gének kifejeződését, ami megmagyarázhatja, hogy a fitoösztrogének miért lehetnek hatékonyak a CRC bizonyos molekuláris altípusaiban és -az adenoma-carcinoma szekvencia meghatározott stádiumában alkalmazva -a CRC prevenciójában vagy kezelésében [42]. Klinikai vizsgálatokban igazolták, hogy a fitoösztrogéneket és növényi rostokat tartalmazó Eviendep (CM&D Pharma Limited, Egyesült Királyság) szedése már rövid távon is hatékonyan csökkenti a FAPos, illetve Lynch-szindrómás betegeknél az emésztőrendszeri polipok számát és méretét [43,44], és ezzel…”