In 2020, life expectancy was 79.2 years for men and 85.3 years for women, in France, according to the National Institute of Demographic Studies (INED). A difference that science is trying to understand.
Without germ cells, life expectancy is the same
A new study, published in the journal Science Advances, may have just solved the mystery. During their work, they carried out experiments on killies, freshwater turquoise mole fish.
“The aging process in killifish is similar to that of humans, so I don’t think humans are necessarily more complicated, explained Tohru Ishitani, lead author of the study, to the media The Guardian. This research will be a springboard for understanding the control of aging in humans.”
The researchers based their work on one of the biggest differences between the two sexes: sperm and eggs. During their experiments on killies, they stopped the production of germ cells, which are the origin of gametes, sperm for men, eggs for women.
Results: They observed that without germ cell production, men lived longer and women died younger, meaning that both sexes had a similar life expectancy.
“We expected that removing germ cells would extend the lifespan of both men and women, but it only extends the lifespan of men and shortens the lifespan of women, underlines Tohru Ishitani. It was unexpected, but we realized that this discovery could [permettre de mieux comprendre] differences in life expectancy between the sexes.“
Lack of sperm increases vitamin D production
In detail, the absence of gamete production, both male and female, has repercussions on the health of fish. In females, scientists observed hormonal changes that impact the maintenance of healthy tissues, as well as a reduction in estrogen, which increased the risk of cardiovascular disease. On the male side, on the other hand, they produced more vitamin D, which could explain their better bone, muscle and skin health.
At the same time, the team administered vitamin D to the fish in order to measure the impact of this single element on life expectancy. This was increased by 21% for men and 7% for women. Even if they are interesting, these results are currently only valid in animals. It is not certain that they are observed in humans.
As a reminder, according to the National Agency for Food, Environmental and Occupational Health Safety (ANSES), an adult should consume 15 micrograms of vitamin D every day, according to nutritional references for the population (RNP).
A quantity that should not be exceeded because excessively high intakes can cause side effects such as weight loss, headaches, nausea, vomiting, intense fatigue, but also more serious health problems: cardiovascular or renal. or even one hypercalcemia.
