Increased dietary fiber consumption has been associated with many beneficial effects, including amelioration of obesity and insulin resistance. These effects may be due to the increased production of short chain fatty acids, including propionate, acetate and butyrate, during fermentation of the dietary fiber in the colon. Indeed, oral and dietary supplementation of butyrate alone has been shown to prevent high fat-diet induced obesity and insulin resistance. This review focuses on sources of short chain fatty acids, with emphasis on sources of butyrate, mechanisms of fiber and butyrate metabolism in the gut and its protective effects on colon cancer and the peripheral effects of butyrate supplementation in peripheral tissues in the prevention and reversal of obesity and insulin resistance.

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Skeletal muscle mitochondrial dysfunction, evidenced by incomplete beta oxidation and accumulation of fatty acid intermediates in the form of long and medium chain acylcarnitines, may contribute to ectopic lipid deposition and insulin resistance during high fat diet (HFD)-induced obesity. The present review discusses the roles of anterograde and retrograde communication in nucleo-mitochondrial crosstalk that determines skeletal muscle mitochondrial adaptations, specifically alterations in mitochondrial number and function in relation to obesity and insulin resistance. Special emphasis is placed on the effects of high fat diet (HFD) feeding on expression of nuclear-encoded mitochondrial genes (NEMGs) nuclear receptor factor 1 (NRF-1) and 2 (NRF-2) and peroxisome proliferator receptor gamma coactivator 1 alpha (PGC-1α) in the onset and progression of insulin resistance during obesity and how HFD-induced alterations in NEMG expression affect skeletal muscle mitochondrial adaptations in relation to beta oxidation of fatty acids. Finally, the potential ability of acylcarnitines or fatty acid intermediates resulting from mitochondrial beta oxidation to act as retrograde signals in nucleo-mitochondrial crosstalk is reviewed and discussed.

The effect of pornography on sexual response is understudied, particularly among women. A multinational, community-based sample of 2433 women at least 18 years of age completed a 42-item, opt-in questionnaire collecting information on demographic and sexual history characteristics, use of pornography during masturbation, frequency of pornography use, and sexual response parameters. Pornography use and average frequency were compared across demographic variables. We also examined how pornography frequency predicted differences in self-reported arousal difficulty; orgasmic difficulty, latency, and pleasure; and the percent of sexual activities ending in orgasm during both masturbation and partnered sex. On average, women using pornography were younger, and reported more interest in sex. Pornography frequency differed significantly by menopausal status, sexual orientation, anxiety/depression status, number of sexual partners, and origin of data collection. During masturbation, more frequent pornography use predicted lower arousal difficulty and orgasmic difficulty, greater pleasure, and a higher percentage of masturbatory events leading to orgasm. Frequency of pornography use predicted only lower arousal difficulty and longer orgasmic latencies during partnered sex, having no effect on the other outcome variables. Pornography use frequency did not predict overall relationship satisfaction or sexual relationship satisfaction. Overall, more frequent pornography use was generally associated with more favorable sexual response outcomes during masturbation, while not affecting most partnered sex parameters. Several demographic and relationship covariates appear to more consistently and strongly predict orgasmic problems during partnered sexual activity than pornography use.

Introduction The criteria for premature ejaculation (PE) have generally been limited to the diagnosis of heterosexual men engaging in penile-vaginal intercourse and therefore the applicability of PE diagnostic criteria to gay men and to activities beyond penile-vaginal intercourse has yet to be explored in depth. Aim To compare the prevalence of PE in gay and straight men and to assess whether PE-related diagnostic measures (ejaculatory control, ejaculation latency [EL], and bother/distress) can be applied with confidence to gay men or to men engaging in sexual activities other than penile-vaginal intercourse. Methods Gay and straight participants (n = 3878) were recruited to take an online survey assessing sexual orientation, sexual function/dysfunction (including specific PE-related measures), sexual relationship satisfaction, and various other sexual behaviors during partnered sex or masturbation. Outcomes Comparison of ejaculatory control, EL, and bother/distress across gay and straight men, as well as across different types of sexual activities. Results A slightly lower PE prevalence among gay men became undetectable when other predictors of prevalence were included in a multivariate analysis (aOR = 0.87 [95% CI: 0.60–1.22]). Gay men with PE reported longer typical ELs (zU = -3.35, P < .001) and lower distress (zU = 3.68, P < .001) relative to straight men, but longer ELs and lower distress were also associated with anal sex. Clinical Translation Clinicians can feel confident about using existing criteria for the diagnosis of PE in gay men but should be aware of potentially longer ELs and lower PE-related bother/distress—probably related to the practice of anal sex—compared with straight men. Strengths and Limitations Although well-powered and international in scope, this study was limited by biases inherent to online surveys, the lack of a sizable sample of bisexual men, and a lack of differentiation between men with acquired vs lifelong PE. Conclusions Irrespective of sexual orientation, gay and straight men with PE reported shorter ELs, lower satisfaction, and greater bother/distress than functional counterparts. While PE-related diagnostic criteria (ejaculatory control, EL, and bother/distress) are applicable to gay men, accommodation for longer ELs and lower bother/distress in gay men should be considered.

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The lack of empirically based diagnostic criteria for delayed ejaculation (DE) not only undermines confidence in the reported prevalence rates for this sexual dysfunction, but it has also resulted in a lack of validated patient reported outcomes (PROs) for assessing this condition. The current study was designed to describe and evaluate six face-valid variables previously shown to discriminate between men with and without DE for their utility as diagnostic measures for DE. A sample of 1285 men (mean age = 37.8, SD = 12.7) free of erectile problems and premature ejaculation completed an online sexual health survey that included potential questions intended for use in the diagnosis of DE. Questionnaire items included ones reflective of previously proposed diagnostic constructs related to DE: ejaculation timing/latency, ejaculation efficacy/control, and negative effects of DE. Results indicated that five of the six proposed items showed moderate intercorrelations, suggesting that each constituted a distinct (i.e., non-redundant) though relevant criterion related to the diagnosis of DE. Based on the level of interrelatedness, the better items representing each construct were included in commonality analysis to assess their unique contributions to the diagnosis of DE. Perceived lack of ejaculatory efficacy/control contributed the largest portion of the variance to the diagnosis of DE (58%), with bother/distress (an index of the negative effects of DE) contributing the second largest portion (25%), and ejaculation timing/latency contributing only a small portion of the variance (6%) to the diagnosis of DE. The relevance of these findings to developing a patient report outcome (PRO) for diagnosing DE that considers both empirically supported questions/items and an appropriate balance of items regarding the three constructs was discussed.