Dietary components and their effects on human sperm quality - A molecular approach

Abstract

[eng] In the last decades, cases of male infertility have been related to different external factors such as alcohol intake, smoking, different chemical compounds or the administration of certain drugs. More recent research revealed that also the diet and its components might have contributed to the observed increase in male infertility, specifically, through its effect on sperm quality. A lot of studies focusing on this relationship are purely epidemiological, although a growing understanding of the molecular mechanisms involved in the formation, development and maturation of sperm is available. The objective of this bachelor thesis is to clarify the molecular mechanism that might be involved in the effect of different diets and its dietary components on sperm quality. In order to carry out this bachelor thesis PubMed has been the main information source used. As a result, several possible mechanisms how dietary components may modulate sperm quality parameters could be identified. In this context, red or processed meat is able to affect sRNA and tRNA involved in the sperm maturation process leading to a reduction in sperm number, whereas the evaluation of seafood, another source of protein, is a complex task as this food, in general, has a positive influence on sperm count, but this effect may be overcompensated depending on the amount of its main contaminant methyl mercury. An insufficient supplementation of certain vitamins, in particular C and E, but also trace elements (zinc and selenium) increases the number of reactive oxygen species, to which spermatozoa are especially sensitive, leading to nucleotide modifications, strand break of the DNA and chromatin cross-linking. The mentioned trace elements may also play a role in male reproductive epigenetics by acting on enzymes adding or removing epigenetic marks of the germ cells during spermatogenesis. Consequently, some diets, for example the Mediterranean Diet, have to be considered more beneficial to maintain the quality of the sperm than others, for example the Western Diet.