Effect of a tomato drink intervention on insulin-like growth factor (IGF)-1 serum levels in healthy subjects.

There is concern that dietary factors can modulate the insulin-like growth factor (IGF) system. The aim of this work was to evaluate the effect ofa tomato drink intervention providing small amounts of lycopene and other carotenoids on serum levels of IGF-1. Twenty healthy young subjects participated in a repeated measure double-blind, cross-over design. Subjects consumed 250 ml of a tomato drink or a placebo drink for 26 days separated by 26 days wash-out. The tomato drink intake increased plasma lycopene, phytoene, phytofluene, and beta-carotene concentrations by 0.22, 0.12, 0.13, and 0.18 mu mol/L, respectively (P < 0.05). No significant effect of the tomato drink intake on IGF-1 levels was observed However, changes in lycopene before and after each experimental period were inversely and significantly correlated with those of IGF-1 (r = -0.33, P < 0. 05, N = 20). No correlation was found with the other carotenoids. A significant reduction of IGF-1 serum level (-5.7%) was observed in subjects (n = 11) with the highest plasma lycopene response but also IGF-1 levels following the tomato drink intake (P < 0. 05). No effect was evident after the placebo treatment. The results suggest that further exploration of the role of tomato lycopene on IGF-1 modulation both on healthy and on subjects at risk is necessary.