A worldwide survey found that sperm quality in healthy men declined year by year. sperm quality may be impaired by some environmental and lifestyle factors, among which obesity and related diseases such as type 2 diabetes are well-known risk factors for poor sperm quality. In previous studies, scientists found that male fruit flies ingested excess sugar shortly before mating, and they tended to produce overweight offspring.
studies on mice have shown that small rna fragments known as tsrna (trna derive dsmall rna) play a role in epigenetic regulation of the next generation. These RNA fragments are found in the sperm of many species, including humans, fruit flies, and mice with very abundant sperm. so far, its function is not clear. in general, rna plays a crucial role in establishing epigenetic states, including heterochromatin formation and transposable silencing in germ cells. whether tsrna of human sperm responds to dietary interventions and is associated with changes in sperm quality has not been investigated.
Swedish Link? The team from ping university looked at whether high glucose intake affects rna fragments in human sperm. Their results were recently published in PLOS Biology entitled Humanspermdisplaysrapidresponsestodiet.
The study looked at 15 normal, non-smoking young people who followed a diet and got all the food from scientists within two weeks. Diets are based on nutritional advice from a healthy Nordic diet, with one exception: in the second week, researchers add about a litre of carbonated drink or 450g of sugar to their day. sperm quality and other health indicators were investigated at the beginning of the study, during the first week (during which they ate a healthy diet), and in the second week (when participants took an extra large amount of sugar). At the beginning of the study, a third of the participants had low sperm motility. motility is one of several factors affecting sperm quality, and the low sperm motility population in the study corresponded to this proportion in the general population. The researchers were surprised to find that sperm activity became normal in all participants during the study.
The researchers also found that small RNA fragments associated with sperm motility also changed. They now plan to continue the work and investigate whether there is a link between male fertility and RNA fragments in sperm. They will also determine whether the RNA code can be used in new diagnostic methods to measure the quality of sperm during IVF.
Taken together, studies have shown that sperm motility can change in a short time (two weeks) and appears to be closely related to diet. which has important clinical significance. The next step is for scientists to continue research to link changes to specific molecules in sperm.