The effects of lycopene supplementation on insulin-like growth factor-1 and insulin-like growth factor binding proteins: A systematic review of randomized controlled trials

Lycopene has been posited to regulate insulin-like growth factor-1 (IGF-1). We aimed to conduct a systematic review of the effects of lycopene on circulating IGF-1 and insulin-like growth factor binding proteins (IGFBPs) in adults. A systematic search was carried out in PubMed, Scopus, ISI Web of Science, and the Cochrane Library databases for randomized controlled trials (RCTs), published from inception until March 2020. A total of 11 studies fulfilled the selection criteria. Eleven studies examined the effect of lycopene supplementation on IGF-1, one of which reported a significant reduction. Moreover, three, four, and ten studies were found for IGFBP-1, IGFBP-2, and IGFBP-3, respectively; where one study found a significant increase in these proteins. In conclusion, no consistent modifying effect of lycopene supplementation on IGF-1 and IGFBPs levels are evident in the literature. More research is needed to explore the effect of lycopene on IGF-1 system.