Soy-Based Diets and Menopausal Symptoms

Key Takeaways

• Pooled soy trials were associated with lower overall vasomotor symptom burden.
• Hot flash severity and frequency, along with overall psychological wellbeing, also trended in a favorable direction.
• Across 15 randomized trials spanning several dietary patterns, interpretation was limited by heterogeneity, 6–16 week interventions, and self-reported outcomes.

Soy-based dietary interventions were associated with lower vasomotor symptom burden in pooled randomized evidence, with an SMD of –0.50 and 95% CI –0.76 to –0.25. A parallel signal suggested modest improvement in psychological wellbeing, with hot flash severity and frequency also moving in a favorable direction. Published online in Proceedings of the Nutrition Society, the findings came from a review of dietary strategies in women with menopausal symptoms.

The systematic review and meta-analysis evaluated dietary interventions for vasomotor, psychological, and cognitive menopausal symptoms across 15 randomized controlled trials involving 1,952 participants. Eligible studies enrolled women aged 40–65 years with menopause, perimenopause, or postmenopausal symptoms, and also included trials reporting relevant outcomes when menopause was not explicitly named. Investigators used Cochrane methods, followed PRISMA guidance, and registered the protocol in PROSPERO as CRD42024610754 after database searches in CINAHL, Cochrane, Embase, PubMed, and PsycINFO. Interventions ranged from soy and low-fat vegan diets to flaxseed, lacto-ovo-vegetarian, reduced-calorie, MIND, DASH, and intermittent fasting patterns, but only soy generated pooled randomized symptom estimates.

Within the pooled soy evidence, six trials linked the interventions with lower vasomotor symptoms overall, yielding an SMD of –0.50 with 95% CI –0.76 to –0.25. Heterogeneity for that analysis was I² 84%, an important qualifier when considering the consistency of the pooled result. A separate estimate for hot flash severity and frequency showed SMD –0.59, with 95% CI –0.88 to –0.31 and I² 69%. Overall, the vasomotor signal was favorable, though it was accompanied by substantial between-study variability.

Psychological outcomes were also pooled for soy-based interventions, with overall wellbeing showing an SMD of –0.25, 95% CI –0.50 to –0.01, and I² 0%. Outside those pooled analyses, narrative synthesis showed inconsistent vasomotor findings for flaxseed rather than a consistent directional pattern. Small improvements in depressive symptoms were observed with DASH and lacto-ovo-vegetarian diets, while cognitive benefit was reported with the MIND diet. Some interventions, including intermittent fasting, showed minimal benefit, leaving the broader dietary evidence mixed beyond the pooled soy analyses.

Most interventions lasted only 6–16 weeks, and outcome assessment relied largely on self-reported symptom measures across the included trials. The authors characterized soy-based interventions as showing promise, while calling for further research on whole dietary patterns and longer-term adherence-related benefits. The findings remained cautious and specific to the women represented in the randomized trials.