Comparing Effects of a Low-energy Diet and a High-protein Low-fat Diet on Sexual and Endothelial Function, Urinary Tract Symptoms, and Inflammation in Obese Diabetic Men

Abstract

Introduction Abdominal obesity and type 2 diabetes mellitus are associated with sexual and endothelial dysfunction, lower urinary tract symptoms (LUTS), and chronic systemic inflammation. Aim To determine the effects of diet-induced weight loss and maintenance on sexual and endothelial function, LUTS, and inflammatory markers in obese diabetic men. Main Outcome Measures Weight, waist circumference (WC), International Index of Erectile Function (IIEF-5) score, Sexual Desire Inventory (SDI) score, International Prostate Symptom Scale (IPSS) score, plasma fasting glucose and lipids, testosterone, sex hormone binding globulin (SHBG), inflammatory markers (high-sensitivity C-reactive protein [CRP] and interleukin-6 [IL-6]) and soluble E-selectin, and brachial artery flow-mediated dilatation (FMD) were measured at baseline, 8 weeks, and 52 weeks. Methods Over 8 weeks, 31 abdominally obese (body mass index ≥ 30 kg/m2, WC ≥ 102 cm), type 2 diabetic men (mean age 59.7 years) received either a meal replacement-based low-calorie diet (LCD) ∼1,000 kcal/day (N = 19) or low-fat, high-protein, reduced-carbohydrate (HP) diet (N = 12) prescribed to decrease intake by ∼600 kcal/day. Subjects continued on, or were switched to, the HP diet for another 44 weeks. Results At 8 weeks, weight and WC decreased by ∼10% and ∼5% with the LCD and HP diet, respectively. Both diets significantly improved plasma glucose, low-density lipoprotein (LDL), SHBG, IIEF-5, SDI and IPSS scores, and endothelial function (increased FMD, reduced soluble E-selectin). Erectile function, sexual desire, and urinary symptoms improved by a similar degree with both diets. CRP and IL-6 decreased with the HP diet. At 52 weeks, reductions in weight, WC, and CRP were maintained. IIEF-5, SDI, and IPSS scores improved further. Conclusions Diet-induced weight loss induces rapid improvement of sexual, urinary, and endothelial function in obese diabetic men. A high-protein, carbohydrate-reduced, low-fat diet also reduces systemic inflammation and sustains these beneficial effects to 1 year.

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

“…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).…”

Clinical Effectiveness of Weight Loss and Weight Maintenance Interventions for Men: A Systematic Review of Men-Only Randomized Controlled Trials (The ROMEO Project)

“…The pilot trial conducted by Pavlou et al (1989) and three other trials (Benassi-Evans et al, 2009;Khoo et al, 2011;Wycherley et al, 2012) examined varying the protein, carbohydrate, and fat proportions of reducing diets, or examined a more stringent initial calorie prescription of 900 kcal for 8 weeks followed by a 600 kcal/day deficit to 600 kcal/day deficit alone. None of the trials identified significant differences between the different dietary approaches after 12 months.…”

“…Of these, 21 reports (14 RCTs [Benassi-Evans, Clifton, Noakes, Keogh, & Fenech, 2009;Borg, Kukkonen-Harjula, Fogelholm, & Pasanen, 2002;Esposito et al, 2004;Hunt et al, 2014;Jeffery, Gerber, Rosenthal, & Lindquist, 1983;Khoo et al, 2011;King, Frey-Hewitt, Dreon, & Wood, 1989;Morgan, Lubans, Collins, Warren, & Callister, 2011;Patrick et al, 2011;Pavlou, Krey, & Steffee, 1989;Van Aggel-Leijssen, Saris, Hul, & van Baak, 2001;Wood et al, 1988;Wycherley, Brinkworth, Clifton, & Noakes, 2012] with seven linked reports [Collins et al, 2013;Fortmann, Haskell, & Wood, 1988; Jeffery, BjornsonBenson, Rosenthal, Lindquist, & Johnson, 1984;Kukkonen-Harjula, Borg, Nenonen, & Fogelholm, 2005; Lejeune, Aggel-Leijssen, van Baak, & WesterterpPlantenga, 2003;Lutze et al, 2013; Multiple Risk Factor Intervention Trial Research Group, 1982; Van AggelLeijssen, Saris, Hul, & van-Baak, 2002]) were eligible for inclusion. Details of the flow chart for the results of the literature search and a description of all the included trials are provided in Appendices C and D.…”

“…Four trials were carried out in Australia (Benassi-Evans et al, 2009;Khoo et al, 2011;Morgan et al, 2011;Wycherley et al, 2012); and studies conducted by Borg et al (2002), Esposito et al (2004), Hunt et al (2014), and van Aggel- Leijssen et al (2001) were conducted in Finland, Italy, the United Kingdom, and the Netherlands, respectively. The majority of trials investigated weight loss interventions.…”

The action of herbal medicine on the libido: aspects of nutritional intervention in increasing sexual desire

“…As visceral adiposity and insulin resistance are associated with the production of inflammatory cytokines and with the aromatization of testosterone into estradiol in the adipose tissue, weight loss leads to the release of pituitary gonadotropin and to the production of testicular androgens, in turn improving the sexual function. The strong points in the study are the comprehensive evaluations, parallel dietetic approaches, and relatively long duration [26].…”