1.
Effects of alcohol on insulin-like growth factor I and insulin-like growth factor binding protein 3 in postmenopausal women.
Lavigne, JA, Baer, DJ, Wimbrow, HH, Albert, PS, Brown, ED, Judd, JT, Campbell, WS, Giffen, CA, Dorgan, JF, Hartman, TJ, et al
The American journal of clinical nutrition. 2005;81(2):503-7
-
-
-
Free full text
-
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.
2.
Effects of a 2-year randomized soy intervention on sex hormone levels in premenopausal women.
Maskarinec, G, Franke, AA, Williams, AE, Hebshi, S, Oshiro, C, Murphy, S, Stanczyk, FZ
Cancer epidemiology, biomarkers & prevention : a publication of the American Association for Cancer Research, cosponsored by the American Society of Preventive Oncology. 2004;13(11 Pt 1):1736-44
-
-
Plain language summary
Countries that have a high consumption of soy, such as Japan and China, tend to have lower breast cancer rates. Soy contains isoflavones, phytoestrogens which may have oestrogenic and antieostrogenic effects. The aim of this trial was to examine the effect of soy foods on menstrual cycle length and circulating sex hormone levels. 189 healthy premenopausal women completed the 2-year study, during which the treatment group consumed two daily servings of soy foods (tofu, soy milk, roasted soy nuts, soy protein powder or soy protein bars) containing a total of 50 mg of isoflavones. The control group maintained their regular diet. Blood samples were taken 5 days after ovulation in months 0, 3, 6, 12 and 24. Soy did not have any significant effects on the levels of circulating sex hormones or length of menstrual cycle. The authors concluded that any preventative effects of soy on breast cancer risk may be mediated by mechanisms other than its effect on circulating sex hormone levels.
Abstract
OBJECTIVE Several epidemiologic studies have described protective effects of soy consumption against breast cancer. The goal of this trial among premenopausal women was to examine the effect of soy foods on menstrual cycle length and circulating sex hormone levels. METHODS This 2-year dietary intervention randomized 220 healthy premenopausal women. The intervention group consumed two daily servings of soy foods containing approximately 50 mg of isoflavones; the control group maintained their regular diet. Five blood samples (obtained in months 0, 3, 6, 12, and 24) were taken 5 days after ovulation as determined by an ovulation kit. The serum samples were analyzed for estrone, estradiol, sex hormone binding globulin, androstenedione, and progesterone by immunoassay. RESULTS At baseline, both groups had similar demographic, anthropometric, and nutritional characteristics. The dropout rates of 15.6% (17 of 109) in the intervention group and 12.6% (14 of 111) in the control group did not differ significantly. According to soy intake logs, 24-hour recalls, and urinary isoflavone excretion, the women closely adhered to the study regimen. Menstrual cycles became slightly shorter in both groups but did not differ by group. Mixed general linear models indicated no significant intervention effect on any of the serum hormones. However, androstenedione and progesterone decreased significantly over time in both groups. CONCLUSIONS The results of this study suggest that the preventive effects of soy on breast cancer risk in premenopausal women may not be mediated by circulating sex hormone levels. Different mechanisms of actions or effects of exposure earlier in life are alternate hypotheses that require further investigation.