The effect of soy intervention on insulin‐like growth factor 1 levels: A meta‐analysis of clinical trials

• Published in: Phytotherapy research Vol. 34; no. 7; pp. 1570 - 1577
• Main Authors: Zeng, Jiawei, Feng, Yue, Feng, Jiafu, Chen, Xi
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.07.2020; Wiley Subscription Services, Inc
• Subjects: Clinical trials; Consumption; Dosage; duration; estimation; Glycine max - adverse effects; Growth factors; health status; Humans; IGF‐1; Insulin; insulin-like growth factor I; Insulin-Like Growth Factor I - drug effects; Insulin-like growth factors; Intervention; Meta-analysis; phytotherapy; soy; soya; Subgroups; systematic review; Young Adult; soya; IGF-1; soy; humans
• ISSN: 0951-418X; 1099-1573; 1099-1573
• DOI: 10.1002/ptr.6630

A low insulin‐like growth factor 1 (IGF‐1) level is known to be associated with many disorders. Several studies have shown that soy consumption may influence IGF‐1, but the findings remain inconclusive. In this work, we conducted a systematic review and meta‐analysis to provide a more accurate estimation of the effect of soy consumption on plasma IGF‐1. A comprehensive systematic search was performed in Scopus, Embase, Web of Science, and PubMed/MEDLINE databases from inception until October 2019. Eight studies fulfilled the eligibility criteria. The pooled weighted mean difference (WMD) of the eligible studies was calculated with random‐effects approach. Overall, a significant increment in plasma IGF‐1 was observed following soy intervention (WMD: 13.5 ng/ml, 95% CI: 5.2, 21.8, I2 = 97%). Subgroup analyses demonstrated a significantly greater increase in IGF‐1, when soy was administered at a dosage of ≤40 g/day (WMD: 11.7 ng/ml, 95% CI: 10.9 to 12.6, I2 = 98%), and when the intervention duration was <12 weeks (WMD: 26.6 ng/ml, 95% CI: 9.1 to 44.1, I2 = 0.0%). In addition, soy intervention resulted in a greater increase in IGF‐1 among non‐healthy subjects (WMD: 36 ng/ml, 95% CI: 32.7 to 39.4, I2 = 84%) than healthy subjects (WMD: 9.8 ng/ml, 95% CI: 8.9 to 10.7, I2 = 90%). In conclusion, this study provided the first meta‐analytical evidence that soy intake may increase IGF‐1 levels, but the magnitude of the increase is dependent on the intervention dosage, duration, and health status of the participants.