Effects of alcohol on insulin-like growth factor I and insulin-like growth factor binding protein 3 in postmenopausal women

Background: Increased circulating insulin-like growth factor I (IGF-I) concentrations, frequently adjusted for IGF binding protein 3 (IGFBP-3), have been associated with increased risk of several types of cancer, including colon, prostate, and breast. Studies have suggested that alcohol may affect IGF-I or IGFBP-3; however, controlled feeding studies to assess alcohol’s effects on IGF-I or IGFBP-3 have not been conducted. Objective: To determine whether chronic, moderate alcohol intake affects serum IGF-I or IGFBP-3 concentrations, we performed a controlled, crossover feeding study. Design: Fifty-three postmenopausal women were randomly assigned to consume 0 g (control), 15 g (one drink), or 30 g (2 drinks) alcohol daily for 8 wk and were rotated through the other 2 intake levels in random order. All foods and beverages were provided during the intervention. Individuals were monitored and calories adjustedtomaintainconstantweight,andserumwascollectedatthe end of each diet period. Results: Compared with the effects of 0 g alcohol/d, IGF-I concentrations were nearly unchanged by 15 g alcohol/d (0.8%; 95% CI: 3.2%, 3.5%) but decreased significantly by 4.9% (95% CI: 8.0%, 1.6%) with 30 g alcohol/d. IGFBP-3 concentrations significantly increased by 3.0% (95% CI: 0.4%, 5.6%) with 15 g alcohol/d but did not increase significantly with 30 g/d (1.8%; 95% CI: 0.9%, 4.5%). Conclusions: To our knowledge, this is the first published controlled diet study to find that in postmenopausal women, when weight is kept constant, alcohol consumption reduces the amount of serum IGF-I potentially available for receptor binding. These findingssuggestthattheeffectofalcoholintakeshouldbeconsideredin studies of IGF-I, IGFBP-3, and cancer in postmenopausal women. Am J Clin Nutr 2005;81:503–7.