- E.J. Giltay (1)
- L.J.G. Gooren (1)
- E. Kampman (1)
- C.M. Korse (1)
- J.W. Lampe (1)
- F.E. Leeuwen van (1)
- M.A. Rookus (1)
- P.G. Scheffer (1)
- J.C. Seidell (1)
- T. Teerlink (1)
- L.J. van't Veer (1)
- D.W. Voskuil (1)
- A. Vrieling (1)
- B.J.M. Witteman (1)
Isolated Isoflavones do not affect the circulating insulin-like growth factor system in men at increased colorectal cancer risk
Vrieling, A. ; Rookus, M.A. ; Kampman, E. ; Bonfrer, J.M.G. ; Korse, C.M. ; Doorn, J. van; Lampe, J.W. ; Cats, A. ; Witteman, B.J.M. ; Leeuwen, F.E. van; van't Veer, L.J. ; Voskuil, D.W. - \ 2007
The Journal of Nutrition 137 (2007)2. - ISSN 0022-3166 - p. 379 - 383.
estrogen replacement therapy - red-clover - factor-i - postmenopausal women - binding protein-3 - soy protein - clinical characteristics - premenopausal women - antioxidant status - human health
Epidemiological studies show that increased insulin-like growth factor (IGF)-I concentrations are related to increased colorectal cancer risk. A reduced colorectal cancer risk has been associated with isoflavones, which might affect the IGF-system because of their weak estrogenic activity. We conducted a randomized, placebo-controlled, double-blind crossover study to investigate the effect of an 8-wk isolated isoflavone supplementation (84 mg/d) on serum concentrations of total IGF-I, free IGF-I, total IGF-II, IGF binding protein (BP)-1, IGFBP-2, and IGFBP-3. Additionally, we investigated whether IGF-system component differences were related to concentrations of the more potent estrogenic isoflavone metabolite, equol. Our study population consisted of 37 men with a family history of colorectal cancer or a personal history of colorectal adenomas. Isoflavone supplementation did not significantly affect serum total IGF-I concentrations (relative difference between serum total IGF-I concentrations after isoflavone supplementation and after placebo: ¿1.3%, 95% CI ¿8.6 to 6.0%). Neither free IGF-I, nor total IGF-II, IGFBP-1, IGFBP-2, or IGFBP-3 concentrations were significantly altered. Interestingly, the change in serum IGF-I concentrations after isoflavone supplementation was negatively associated with serum equol concentrations (r = ¿0.49, P = 0.002). In conclusion, isolated isoflavones did not affect the circulating IGF-system in a male high-risk population for colorectal cancer. However, to our knowledge, this is the first study that suggests isoflavones might have an IGF-I lowering effect in equol producers only. This underlines the importance of taking into account equol status in future isoflavone intervention studies
Effects of sex steroids on components of the insulin resistance syndrome in transsexual subjects
Elbers, J.M.H. ; Giltay, E.J. ; Teerlink, T. ; Scheffer, P.G. ; Asscheman, H. ; Seidell, J.C. ; Gooren, L.J.G. - \ 2003
Clinical Endocrinology 58 (2003)5. - ISSN 0300-0664 - p. 562 - 571.
coronary heart-disease - estrogen replacement therapy - lipoprotein particle-size - human postheparin plasma - male-female differences - body-fat distribution - postmenopausal women - cardiovascular-disease - hepatic lipase - risk-factors
objective Sex differences are found in most components of the insulin resistance syndrome and the associated cardiovascular risk profile. These differences are attributed to sex-specific sex steroid profiles, but the effects of sex steroids on the individual components of the insulin resistance syndrome remain incompletely understood. design Prospective, intervention study. subjects In 37 young (age range 16¿36 years), nonobese [body mass index (BMI) <29], transsexual subjects, effects of ethinyl oestradiol (100 µg/day) + cyproterone acetate (100 mg/day) administration were evaluated in 20 male-to-female transsexuals and of testosterone-ester administration [250 mg intramuscularly (i.m.)/2 weeks] in 17 female-to-male transsexuals. measurements We studied lipid spectrum, postheparin hepatic lipase (HL) and lipoprotein lipase (LPL) activity, blood pressure, glucose utilization (by euglycaemic hyperinsulinaemic clamp), and fat areas (by magnetic resonance imaging) at baseline and during 1-year cross-sex hormone administration. results Oestrogens + antiandrogens increased high-density lipoprotein (HDL)-cholesterol and decreased LDL-cholesterol, and HL activity, which are considered beneficial. But this combination also increased triglycerides, blood pressure, subcutaneous fat and visceral fat, and decreased the LDL-particle size, LPL activity and insulin sensitivity, which are all considered detrimental. Testosterone reduced HDL-cholesterol and the LDL-particle size, and increased triglycerides and HL activity. An android fat distribution was induced (i.e. decreased subcutaneous and increased visceral fat). Blood pressure, total and LDL-cholesterol, LPL activity and insulin sensitivity were mainly unaffected. conclusions The effects of cross-sex hormone treatment ¿ in the dosages used in this study ¿ in healthy, nonobese, young transsexual subjects do not show unequivocally that female sex steroids, given in large amounts to male subjects, have beneficial effects on cardiovascular profile and that high dose testosterone administration to female subjects is detrimental with respect to cardiovascular risk.