Eggs and sperm, these major elements in human reproduction, could provide an answer to women’s longer lifespan. In 2019, the life expectancy of European women was estimated at 84 years compared to 78.5 years for men, although this varies significantly by country. The discoveries made by Japanese researchers to try to find an explanation for this 5-year difference were tested on the turquoise killifish, a freshwater fish with the scientific name Nothobranchius furzeri.
They realized that this difference could come from germ cells, in other words, gametes corresponding to eggs and sperm. Their goal was to discover how these could influence the lifespan of vertebrates, as it had been proven that they were important in invertebrates.
The longevity of the killifish is very short, spanning only a few months. But its aging process strangely resembles that of humans, as well as the difference in life expectancy between females and males in this species, as highlighted by Japanese researchers.
They tried to remove the germ cells from these fish to check their impact. They found that without them, the difference in longevity was altered. «Without germ cells, male killifish lived longer than usual, while the average lifespan of females shortened,» said the study’s lead author, Kota Abe.
Following this finding, the researchers wanted to show what elements could cause this change.
Without eggs, female killifish no longer produced estrogen, increasing the risk of cardiovascular disease. Males, on the other hand, produced more vitamin D in their liver by not producing sperm. This leads to better bone health, as well as muscles and skin.
They then tried to administer more vitamin D to the killifish, which positively influenced their lifespan by increasing it by 21% in males and 7% in females. For those interested in obtaining it, the researchers who conducted this study advise following the prescribed doses without overdoing it. The British media The Guardian notes that in the UK, health officials recommend a daily supplement of 10 micrograms or 400 IU of vitamin D in autumn and winter.
In conclusion, the study sheds light on the role of germ cells in the lifespan of vertebrates and how they can impact health and longevity. Understanding these mechanisms could potentially lead to new insights into aging and disease prevention in humans. The findings underscore the importance of balanced nutrition and the potential benefits of vitamin supplementation in maintaining a healthy lifespan.