Effects of a low-energy diet on sexual function and lower urinary tract symptoms in obese men

Khoo, Joan; Piantadosi, Cynthia; Worthley, Stephen G.; Wittert, Gary

doi:10.1038/ijo.2010.76

Cited by 116 publications

(99 citation statements)

References 36 publications

(72 reference statements)

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“…Few randomized clinical studies have specifically evaluated the impact of diet and physical activity on testosterone levels in obese men. The results of these studies are essentially conflicting: some of them showed an increase of testosterone (26,27,28,29,30,31,32,33,34), others showed no change (35,36,37,38,39), and one small study has shown even a decrease in testosterone levels (40). Similarly, in the last 10 years, several trials have evaluated the impact of bariatric surgery on testosterone levels in men generally, showing an increase in testosterone levels (41,42,43,44,45,46,47,48).…”

Section: Introductionmentioning

confidence: 97%

Body weight loss reverts obesity-associated hypogonadotropic hypogonadism: a systematic review and meta-analysis

Corona

Rastrelli

Monami

et al. 2013

European Journal of Endocrinology

346

290

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Objective: Few randomized clinical studies have evaluated the impact of diet and physical activity on testosterone levels in obese men with conflicting results. Conversely, studies on bariatric surgery in men generally have shown an increase in testosterone levels. The aim of this study is to perform a systematic review and meta-analysis of available trials on the effect of body weight loss on sex hormones levels. Design: Meta-analysis. Methods: An extensive Medline search was performed including the following words: 'testosterone', 'diet', 'weight loss', 'bariatric surgery', and 'males'. The search was restricted to data from January 1, 1969 up to August 31, 2012. Results: Out of 266 retrieved articles, 24 were included in the study. Of the latter, 22 evaluated the effect of diet or bariatric surgery, whereas two compared diet and bariatric surgery. Overall, both a lowcalorie diet and bariatric surgery are associated with a significant (P!0.0001) increase in plasma sex hormone-binding globulin-bound and -unbound testosterone levels (total testosterone (TT)), with bariatric surgery being more effective in comparison with the low-calorie diet (TT increase: 8.73 (6.51-10.95) vs 2.87 (1.68-4.07) for bariatric surgery and the low-calorie diet, respectively; both P!0.0001 vs baseline). Androgen rise is greater in those patients who lose more weight as well as in younger, non-diabetic subjects with a greater degree of obesity. Body weight loss is also associated with a decrease in estradiol and an increase in gonadotropins levels. Multiple regression analysis shows that the degree of body weight loss is the best determinant of TT rise (BZ2.50G0.98, PZ0.029). Conclusions: These data show that weight loss is associated with an increase in both bound and unbound testosterone levels. The normalization of sex hormones induced by body weight loss is a possible mechanism contributing to the beneficial effects of surgery in morbid obesity.

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Section: Introductionmentioning

confidence: 97%

Body weight loss reverts obesity-associated hypogonadotropic hypogonadism: a systematic review and meta-analysis

Corona

Rastrelli

Monami

et al. 2013

European Journal of Endocrinology

346

290

View full text Add to dashboard Cite

show abstract

“…Indeed, testosterone therapy promotes metabolically favourable changes in body composition (Wittert et al 2003) associated with moderate decreases in insulin resistance (Grossmann 2011), whereas, conversely ADT given to men with PCa leads to visceral fat gain and increased insulin resistance . In addition, weight loss can lead to substantial increases in testosterone Endocrine-Related Cancer (2012) 19 F47-F62 www.endocrinology-journals.org levels, especially in morbidly obese men (Khoo et al 2010), and this increase in testosterone is proportional to the amount of weight lost (Grossmann 2011). Thus, testosterone has complex interactions not only with prostate biology, but also direct relationships with PCa metabolic risk factors such as diabetes, obesity and the MetS.…”

Section: Relationship Between Sex Steroids and Diabetesmentioning

confidence: 99%

Androgens, diabetes and prostate cancer

Grossmann¹,

Wittert²

2012

Endocrine-Related Cancer

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Metabolic disorders such as diabetes, obesity and the metabolic syndrome have been shown to modulate prostate cancer (PCa) risk and aggressiveness in population-based and experimental studies. While associations between these conditions are modest and complex, two consistent findings have emerged. First, there is observational evidence that obesity and associated insulin excess are linked to increased PCa aggressiveness and worse outcomes. Secondly and somewhat paradoxically, long-standing diabetes may be protective against PCa development. This apparent paradox may be due to the fact that long-standing diabetes is associated with insulin depletion and decreased IGF1 signalling. Men with obesity or diabetes have moderate reductions in their androgen levels. The interconnectedness of metabolic and androgen status complicates the dissection of the individual roles of these factors in PCa development and progression. Metabolic factors and androgens may promote prostate carcinogenesis via multiple mechanisms including inflammation, adipokine action, fatty acid metabolism and IGF signalling. Moreover, androgen deprivation, given to men with PCa, has adverse metabolic consequences that need to be taken into account when estimating the risk benefit ratio of this therapy. In this review, we will discuss the current epidemiological and mechanistic evidence regarding the interactions between metabolic conditions, sex steroids and PCa risk and management.

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“…This suggests that weight loss can lead to genuine reactivation of the gonadal axis by reversal of obesity-associated hypothalamic suppression. Weight loss can also improve quality of live and sexual function in obese men, but whether this is causally related to the associated increase in testosterone levels is not known (Khoo et al 2010). …”

Section: Testosterone and Insulin Resistance: A Bilateral Relationshipmentioning

confidence: 99%

Testosterone and glucose metabolism in men: current concepts and controversies

Grossmann¹

2013

Journal of Endocrinology

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A wealth of observational studies show that low testosterone is associated with insulin resistance and with an increased risk of diabetes and the metabolic syndrome. Experimental studies have identified potential mechanisms by which low testosterone may lead to insulin resistance. Visceral adipose tissue is an important intermediate in this relationship. Actions of testosterone or its metabolite oestradiol on other tissues such as muscle, liver, bone or the brain, and body composition-independent effects may also play a role. However, definitive evidence from randomised controlled trials (RCTs) to clarify whether the association of low testosterone with disordered glucose metabolism is causative is currently lacking. It therefore remains possible that this association is due to reverse causation, or simply originates by association with common health and lifestyle factors. RCTs of testosterone therapy in men with or without diabetes consistently show modest metabolically favourable changes in body composition. Despite this, testosterone effects on glucose metabolism have been inconsistent. Recent evidence suggests that the hypothalamic-pituitary-testicular axis suppression in the majority of obese men with metabolic disorders is functional, and may be, at least in part, reversible with weight loss. Until further evidence is available, lifestyle measures with emphasis on weight reduction, treatment of comorbidities and optimisation of diabetic control should remain the first-line treatment in these men. Such measures, if successful, may be sufficient to normalise testosterone levels in men with metabolic disorders, who typically have only modest reductions in circulating testosterone levels.

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Effects of a low-energy diet on sexual function and lower urinary tract symptoms in obese men

Cited by 116 publications

References 36 publications

Body weight loss reverts obesity-associated hypogonadotropic hypogonadism: a systematic review and meta-analysis

Body weight loss reverts obesity-associated hypogonadotropic hypogonadism: a systematic review and meta-analysis

Androgens, diabetes and prostate cancer

Testosterone and glucose metabolism in men: current concepts and controversies

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