Plain language summary
Both alcohol and the endocrine hormone insulin-like growth factor (IGF-1) have been linked to increased breast cancer risk. However, the link with breast cancer is stronger in pre-menopausal women but most studies have not distinguished between pre and post-menopausal individuals. This randomly controlled, crossover study looked at how IGF-1 and its major binding protein IGFBP-3 were affected by alcohol in 31 pre-menopausal women, it also considered if levels were affected by the menstrual cycle. The study concluded that there is a link between alcohol and the reduction of IGF-1 but no effect on IGFBP-3 They also found that IGF-1 serum levels significantly increase during the later stages of the menstruation cycle regardless of alcohol intake. Further studies are needed to understand the balance of alcohol intake and how that alters an increase or decrease in breast cancer risk.
Abstract
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 adjusted to maintain constant weight, and serum was collected at the 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 findings suggest that the effect of alcohol intake should be considered in studies of IGF-I, IGFBP-3, and cancer in postmenopausal women.
Methodological quality
Jadad score
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1
Allocation concealment
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Not applicable
