Obesity and Male Infertility: Role of Fatty Acids in the Modulation of Sperm Energetic Metabolism

Obesity in men of reproductive age is increasing worldwide, impacting negatively on reproductive potential, sperm function, and assisted reproduction outcomes. Changes in modern eating behaviors are needed to invert the negative correlation between lifestyle and sperm quality. It is known from the literature that fatty acids are able to modulate lipid metabolism by complex mechanisms involving a sequence of interdependent and cross-regulated molecular events. Although a great deal of data is currently available on the dietary modulation of lipid metabolism, little is known about the nutritional regulation of sperm energetic metabolism. In this review, major data from the literature about the role of some dietary fats as modulators of sperm function and quality are described. Moreover, biochemical mechanisms responsible for an impairment or improvement in sperm bioenergetics are critically analyzed. It is noteworthy that both quantitative and qualitative aspects of dietary fats influence sperm function. The administration of a high-fat diet, low in polyunsaturated fatty acids, caused a significant increase in body weight hyperglycemia, hyperinsulinemia, and dyslipidemia, along with a significant reduction in sperm quality. In contrast, unsaturated fatty acids are able to positively influence sperm quality and function. The understanding of the biochemical mechanisms underlying the development of male infertility related to obesity led us to depict a possible framework for the molecular action of fatty acids on sperm quality during dysmetabolic conditions.