High‐energy diets: a threat for male fertility?

Abstract

Male fertility is declining in developed countries, as well as in developing countries. External factors linked to lifestyle, such as eating disorders, negatively affect spermatogenesis, both at central and gonadal levels. The overconsumption of high-energy diets (HED) alters the functioning of the male reproductive axis and consequently affects the testicular physiology, disrupting its metabolism and bioenergetic capacity. Testicular metabolism presents unique characteristics, partly because of its cellular heterogeneity and to the specific functions that each cell type plays within the testicular environment. Disruption of the tightly regulated metabolic pathways leads to adverse reproductive outcomes, such as inefficient energy supply to germ cells, sperm defects or spermatogenesis arrest. Testicular metabolic alterations induced by HED intake may also lead to mitochondrial dysfunction, which is closely associated to reactive oxygen species (ROS) overproduction and oxidative stress. ROS easily target spermatozoa DNA and lipids, contributing to decreased sperm quality. Thus, understanding the detrimental effects of HED overconsumption on the pathways underlying testicular metabolism and sperm production is imperative; otherwise, one may favour a transgenerational amplification of subfertility. Herein, we present an up-to-date overview of the effects of HED on testicular metabolism, sperm parameters and the subsequent consequences for male fertility.

Obesity, energy balance and spermatogenesis

“…Thus, gut and adipose-derived hormones (particularly ghrelin and leptin) have risen as crucial integrators of the link between energy balance, food intake and male reproductive function ( Fig. 1) (Alves et al 2014).…”

“…Accumulation of toxic substances and lipid-soluble endocrine disruptors in fat tissue may also amplify the deleterious effects induced by increased body weight (for review Rato et al 2014). Defective spermatogenesis may result in multiple alterations in sperm parameters, defective capacitation and sperm binding, as well as sperm structural changes (particularly in chromatin).…”

“…Notably, several of these hormones and their downstream signalling molecules regulate glucose and energy metabolism in peripheral organs, including the testis. The energy control in testis has been shown to be pivotal for spermatogenesis (for review Alves et al 2014).…”

The insulin sensitiser metformin regulates chicken Sertoli and germ cell populations

“…For example, if cellular energy balance is positive, such as in the case of obesity and insulin resistance, there is a reduction in reproductive ability in both sexes (Chou et al 2014). Abnormal amenorrhoea in females is the first sign of these adverse effects (Franks et al 1996), and in males there is a decrease in sperm production usually associated with altered sex hormone secretion (Rato et al 2014). One of the most frequent causes of female infertility is polycystic ovary syndrome (PCOS), which affects 5 -10% of women of reproductive age and is frequently associated with insulin resistance.…”

Metabolic Cooperation in Testis as a Pharmacological Target: From Disease to Contraception

“…Although the projections for the number of men suffering from metabolic diseases are disturbing, several authors have cautioned that those numbers may be underestimated since lifestyle factors and the consumption of high-energy diets may aggravate the incidence of metabolic diseases [2]. These diseases are responsible for subfertility/infertility and can also promote several sexual disorders such as erectile dysfunction or retrograde ejaculation [3][4][5]. Thus, it is imperative to disclose the molecular mechanisms responsible for the alterations in male reproductive health and subfertility/infertility in these individuals.…”