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Meta-Analysis
. 2022 Mar-Apr;36(2):556-562.
doi: 10.21873/invivo.12737.

Soy Isoflavones and Breast Cancer Risk: A Meta-analysis

Ioannis Boutas  1 , Adamantia Kontogeorgi  2 , Constantine Dimitrakakis  3 , Sophia N Kalantaridou  2
Affiliations
Meta-Analysis

Soy Isoflavones and Breast Cancer Risk: A Meta-analysis

Ioannis Boutas et al. In Vivo. 2022 Mar-Apr.

Abstract

Background/aim: Soy contains genistein and daidzein isoflavones. Isoflavones are phytoestrogens, with a similarity in structure to human 17-β estradiol hormone. They imitate the action of estrogen on organs by binding and activating estrogen receptors. Numerous studies have examined the relationship between soy consumption and breast cancer but not the amount of consumption itself. We performed a systematic review of the literature in order to determine whether the amount of soy and isoflavones consumed has a positive effect in pre- and post-menopausal women.

Materials and methods: Data gathering was performed following PRISMA guidelines. Narrowing down the result set for all relevant data was performed via title, abstract, full-text evaluation and the snowball procedure. The selected articles had all relevant data extracted. Analysis of the data was performed using Cochrane's Review Manager statistical analysis tool in order to draw conclusions regarding the positive effect for the amount of soy and isoflavones consumed.

Results: Significant results were found when statistically analyzing data from prospective studies which compared soy isoflavones consumption, breast cancer risk and occurrence. The data were indicative of a clear inverse correlation between the amount of isoflavones consumed and breast cancer occurrence in pre- and post-menopausal women.

Conclusion: The consumption of soy isoflavones can reduce the risk of breast cancer in pre-menopausal and post-menopausal women.

Keywords: Soy; breast cancer risk; isoflavones; meta-analysis; review.

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Conflict of interest statement

The Authors declare no conflicts of interest.

Figures

Figure 1
Figure 1. PRISMA flow diagram for study selection.
Figure 2
Figure 2. Forest plot of the prevalence of breast cancer in women in selected studies based on the amount of isoflavones they consumed. CI: Confidence interval.
Figure 3
Figure 3. Forest plot on the prevalence of breast cancer in the total study populations based on the amount of isoflavones they consumed. CI: Confidence interval.
Figure 4
Figure 4. Breast cancer cases based on soy isoflavone consumption for pre-menopausal women in selected studies. CI: Confidence interval.
Figure 5
Figure 5. Breast cancer cases based on soy isoflavone consumption for post-menopausal women in selected studies. CI: Confidence interval.
See this image and copyright information in PMC

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