Study Of The Influence Of Phytochemicals Intakes On Breast Cancer Risk

Objective The purpose of this article is to examine the association between soy isoflavones, tea polyphenols, carotenoids, isothiocyanate consumption and risk of breast cancer incidence by conducting literature review and meta analysis.Method We searched for all relevant studies (Cohort studies, nested case-control studies and case-control study)in CNKI, Wanfang Chinese database, PubMed, Embase (from January1996to September2011). We selected the epidemiological studies that meet the inclusion criteria, and extracted data using a standardized form. The analysis of combine OR/RR and homogeneity was performed using Review Manager. We use Statal2.0Statistical software to conduct Meta regression and examine the potential publication bias by the Egger’s testResult48studies about the association between Phytochemicals consumption and risk of breast cancer incidence met the inclusion criteria. Comparing the highest with the lowest intake:1. Soy isoflavones consumption significantly reduced the breast cancer risk by20%in post-menopausal women (pooled RR=0.80,95%CI:0.71-0.91; I2=34%, p=0.17), but has no significance association in pre-menopausal women. The protective effect of soy isoflavones was only observed among studies conducted in asian women (pooled RR=0.82,95%CI:0.70-0.96; I2=23%, p=0.26) but not in western women (pooled RR=0.98,95%CI:0.90-1.08; I2=33%,P=0.14).2. a-carotene consumption significantly reduced the breast cancer risk by11%(pooled RR=0.89,95%CI:0.83-0.96; I2=24%, p=0.2),(β-carotene consumption significantly reduced the breast cancer risk by11%(pooled RR=0.89,95%CI:0.83-0.96; I2=8%, p=0.37), lutein and zeaxanthin consumption significantly reduced the breast cancer risk by11%(pooled RR=0.91,95%CI:0.84-0.98; I2=9%, p=0.35); There are no significant association between lycopene,(3-cryptoxanthin intake and breast cancer risk.3. Tea polyphenols consumption significantly reduced the breast cancer risk by18%(pooled OR=0.82,95%CI:0.68-0.99; I2=74%, p﹤0.001), tea polyphenols consumption significantly reduced the breast cancer risk (pooled OR=0.76,95%CI:0.59-0.96; I2=80%, p﹤0.001) when data from case-control studies were pooled, but there is no Significance association when cohort studies were pooled (pooled OR=0.97,95%CI:0.80-1.18; I2=18%,p=0.30).4. Isothiocyanate consumption significantly reduced the breast cancer risk by15%(pooled OR=0.85,95%CI:0.75-0.96; I2=61%, p=0.003), it significantly reduced the breast cancer risk by20%in post-menopausal women (pooled OR=0.80,95%CI:0.71-0.91; I2=34%, p=0.17), but has no significant association in pre-menopausal women (pooled OR=0.92,95%CI:0.65-1.30; I2=78%, P=0.001).5. Heterogeneity was exist in the pool analysis of tea polyphenols and isothiocyanates, but it can be explained by subgroup analyzes.Conclusion The food intakes of these4kinds of phytochemicals exert different influence on the breast cancer risk:1. Soy isoflavones consumption may reduce the breast cancer risk in post-menopausal women, it significantly reduced the breast cancer risk in asian populations but not in western populations.2. In all the carotenoids, only α-carotene and βcarotene may reduce the risk of women breast cancer. The evidence about association of lutein and zeaxanthin intake and breast cancer risk are limited, so we can’t make a conclution yet. There are no significant association between lycopene, cryptoxanthin intake and breast cancer risk.3. Isothiocyanate consumption may reduce the breast cancer risk in post-menopausal women.4. The evidence about association of tea polyphenols intake and breast cancer risk are limited, so we can’t make a conclution yet.