• Open Access

Long-term effects of calorie restriction on serum sex-hormone concentrations in men

Authors

  • Roberto Cangemi,

    1. Division of Geriatrics and Nutritional Science and Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO, USA
    2. Department of Experimental Medicine, University of Rome ‘La Sapienza’, Rome Italy
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  • Alberto J. Friedmann,

    1. Division of Geriatrics and Nutritional Science and Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO, USA
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  • John O. Holloszy,

    1. Division of Geriatrics and Nutritional Science and Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO, USA
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  • Luigi Fontana

    1. Division of Geriatrics and Nutritional Science and Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO, USA
    2. The Division of Nutrition and Aging, Istituto Superiore di Sanità, Rome, Italy
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Luigi Fontana, MD, PhD, Washington University School of Medicine, 4566 Scott Avenue, Campus Box 8113, St. Louis, MO 63110, USA. Tel.: +1 314 747 1485; fax: +1 314 362 7657; e-mail:lfontana@dom.wustl.edu

Summary

Calorie restriction (CR) slows aging and consistently reduces circulating sex hormones in laboratory animals. However, nothing is known regarding the long-term effects of CR with adequate nutrition on serum sex-hormone concentration in lean healthy humans. In this study, we measured body composition, and serum total testosterone, total 17-β-estradiol, sex hormone–binding globulin (SHBG), and dehydroepiandrosterone sulfate (DHEA-S) concentrations in 24 men (mean age 51.5 ± 13 years), who had been practicing CR with adequate nutrition for an average of 7.4 ± 4.5 years, in 24 age- and body fat–matched endurance runners (EX), and 24 age-matched sedentary controls eating Western diets (WD). We found that both the CR and EX volunteers had significantly lower body fat than the WD volunteers (total body fat, 8.7 ± 4.2%; 10.5 ± 4.4%; 23.2 ± 6.1%, respectively; P = 0.0001). Serum total testosterone and the free androgen index were significantly lower, and SHBG was higher in the CR group than in the EX and WD groups (P ≤ 0.001). Serum 17β-estradiol and the estradiol:SHBG ratio were both significantly lower in the CR and EX groups than in the WD group (P ≤ 0.005). Serum DHEA-S concentrations were not different between the three groups. These findings demonstrate that, as in long-lived CR rodents, long-term severe CR reduces serum total and free testosterone and increases SHBG concentrations in humans, independently of adiposity. More studies are needed to understand the role of this CR-mediated reduction in sex hormones in modulating the pathogenesis of age-associated chronic diseases such as cancer and the aging process itself.

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