J Int Soc Sports Nutr. 2007 Jul 23;4(1):4. Links
Effect of protein source and resistance training on body composition and sex hormones.
Kalman D, Feldman S, Martinez M, Krieger DR, Tallon MJ.
Miami Research Associates, Nutrition/Endocrinology Division, Miami, Florida, USA.
dkalman@miamiresearch.com.
ABSTRACT: BACKGROUND: Evidence suggests an inverse relationship between soy protein intake and serum concentrations of male sex hormones. Anecdotal evidence indicates that these alterations in serum sex hormones may attenuate changes in lean body mass following resistance training. However, little empirical data exists regarding the effects of soy and milk-based proteins on circulating androgens and exercise induced body composition changes. METHODS: For 12 weeks 20 subjects
were supplemented with 50 g per day of one of four different protein sources (Soy concentrate; Soy isolate; Soy isolate and whey blend, and Whey blend only) in combination with a resistance-training program. Body composition, testosterone, estradiol and sex hormone binding globulin (SHBG) were measured at baseline and week 12. RESULTS: Protein supplementation resulted in a significant increase in lean body mass independent of protein source (0.5 +/- 1.1 and 0.9 +/- 1.4 kg, p = 0.006, p = 0.007). The Testosterone/Estradiol ratio increased across all groups (+13.4, p = 0.005) and estradiol decreased (p = 0.002). Within group analysis showed significant increases in the Testosterone/Estradiol ratio in soy isolate + whey blend group (+16.3, p = 0.030). Estradiol was significantly lower in the whey blend group (-9.1 +/- 8.7 pg/ml, p = 0.033)
No significant differences were observed between groups for total and free testosterone, SHBG, percentage body fat, BMI or body weight.. CONCLUSION: This investigation shows that 12 week supplementation with soy protein does not decrease serum testosterone or inhibit lean body mass changes in subjects engaged in a resistance exercise program.
ללא מביני אנגלית , מדובר על תצרוכת של חלב סויה או מוצרי סויה שונים אשר חשבו שהם משפיעים על עלייה במסה/הורמונים כגון אסטרוגן טסטסטרון ושאר החברים , נמצא שבשימוש 12 שבועות בסויה + מקורות חלבון כאלה ואחרים לא נמצא ירידה אלא אפילו עלייה במסה. כמו כן גם היחס בין טסט לאסטרוגן גדל בכל הקובוצות (נבחנו 4 קבוצות עם תכשירים שונים).
כנראה שמהיום יונקי סויה זו לא ממש קללה
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