PARIS, June 19 — Have scientists found the key to eternal youth? Maybe not, but researchers in Japan suggest that a very specific food could help extend life expectancy.

So, is it a fruit, vegetables, fermented foods or cod liver oil? Actually, it’s small fish, eaten whole, that could play a role in staving off mortality.

The role of diet in health is well documented, in particular the importance of adopting healthy, balanced eating habits to reduce the risk of developing certain diseases.

Many studies point the finger at junk food or ultra-processed foods, while others praise the merits of certain diets such as the Mediterranean diet or the Planetary Health Diet, which is said to be as beneficial to the environment as it is to health.

Researchers in Japan now support the idea that certain foods can have a positive or negative impact on health.

Their work suggests that regular consumption of whole small fish, such as those often served deep-fried, could be beneficial in prolonging life expectancy.

The scientists specifically based their work on a potential association between the consumption of small fish and mortality risk in Japanese adults. No fewer than 80,802 people aged between 35 and 69, including 34,555 men and 46,247 women, were included in the study.

The researchers not only assessed the frequency of their consumption of small fish — such as whitebait, Atlantic capelin, Japanese smelt and small dried sardines — but also followed them for nine years.

They noted the deaths of 2,482 participants, more than half of them from cancer.

Significant reduction in all-cause and cancer mortality among women

Published in the journal Public Health Nutrition, their findings showed a reduction in all-cause and cancer mortality among participants who regularly consumed whole small fish.

But this association was much more significant in women, even though the results do not indicate a proportional link with consumption frequency. In other words, the scientists found no significant difference in mortality risk reduction between women who ate whole small fish 1 to 3 times a month or 3 or more times a week.

"The risk of all-cause and cancer mortality in men showed a similar trend to that in women, although it was not statistically significant.

The reasons ... remain unclear, but the researchers posit that the limited number of male subjects or other factors not measured in the study, such as the portion size of small fish, may also matter.

According to the researchers, the difference in the cancer type causing cancer mortality among sexes may be related to a sex-specific association,” the study news release explains.

The question of life expectancy

This is not the first time that researchers have investigated the benefits of fish-based dishes, and their effects on health have already been demonstrated.

In France, for example, the Programme National Nutrition Santé (PNNS) recommends taking inspiration from the Mediterranean diet, in particular for its richness in Omega-3, largely from oily fish.

This is described as being essential "for the proper functioning of the body,” and "it prevents cardiovascular disease and has a positive effect on maintaining mental health.”

While this Japanese study tends to confirm the beneficial effects of fish consumption, and especially of small fish that can be eaten whole, more in-depth research is needed on other populations.

One issue with these findings is that this type of food is not widely accessible to all. "The habit of eating small fish is usually limited to several coastal or maritime countries, such as Japan.

However, we suspect that the intake of small fish anywhere may be revealed as a way to prolong life expectancy.

Further evidence is necessary to elucidate the potential role of the intake of small fish in mortality risk,” concludes study coauthor, Takashi Tamura.

In parallel with this research, a study published on June 12 in the journal Science Advances has attempted to unravel one of the many mysteries surrounding life expectancy, namely why women tend to live longer than men.

After conducting an experiment on small freshwater fish called killifish, Japanese researchers suggest that germ cells, which are responsible for egg and sperm formation, could explain this phenomenon. — ETX Studio