Does phytoestrogen supplementation improve cognition in humans? A systematic review

Area of Science:

• Neuroscience
• Pharmacology
• Gerontology

Background:

• Phytoestrogens, like resveratrol, are plant compounds with potential health benefits.
• Resveratrol has shown promise in improving cognitive function, especially in postmenopausal women, by enhancing cerebral blood flow.

Purpose of the Study:

• To examine the effects of phytoestrogen supplementation on cognitive function.
• To compare the cognitive benefits of resveratrol with other phytoestrogens, such as isoflavones.

Main Methods:

• Systematic review and meta-analysis of randomized controlled trials (RCTs).
• Searched databases for RCTs using terms for phytoestrogens and cognition.
• Calculated effect sizes for cognitive changes.

Main Results:

• Identified 23 RCTs (15 on isoflavones, 8 on resveratrol/grape).
• Soy isoflavones showed medium cognitive benefits in 6 studies, especially in early postmenopausal women (<6 months).
• Resveratrol demonstrated small-to-medium cognitive benefits in 4 studies (older adults, postmenopausal women) at 150-200 mg/day for ≥14 weeks, linked to improved cerebral perfusion.

Conclusions:

• Soy isoflavone and resveratrol supplementation can improve executive function and memory in cognitively normal older adults.
• Benefits were observed in about half of the studies, primarily with medium effect sizes.
• Red clover and grape formulations did not show significant cognitive benefits.