Soy and Isoflavone Consumption and Multiple Health Outcomes: Umbrella Review of Systematic Reviews and Meta-Analyses of Observational Studies and Randomized Trials in Humans

Abstract

Scope: To assess the existing evidence of associations between consumption of soy and isoflavone and multiple health outcomes.

Methods and results: This is an umbrella review of meta-analyses and systematic reviews of randomized trials and observational studies in humans. 114 Meta-analyses and systematic reviews are identified with 43 unique outcomes. Soy and isoflavone consumption seems more beneficial than harmful for a series of health outcomes. Beneficial associations are identified for cancers, cardiovascular disease, gynecological, metabolic, musculoskeletal, endocrine, neurological, and renal outcomes, particularly in perimenopausal women. Harmful association is only found for gastric cancer (RR: 1.17, 95% CI: 1.02-1.36) for high intake of miso soup (1-5 cups per day) in male.

Conclusion: Generally, soy and isoflavone consumption is more beneficial than harmful. The results herein support promoting soy intake as part of a healthy diet. Randomized controlled trials are necessary to confirm this finding.

Keywords: health; isoflavones; meta-analysis; soy; systematic review; umbrella review.