Israeli scientists are convinced the maximum life span can be increased to 140 years or more, if science treats not only diseases but also specifically tackles the aging processes.

That’s quite a boast, given that the longest confirmed life span so far is 122 years. That honor goes to Frenchwoman Jeanne Louise Calment, who was born in 1875 and died in August 1997. She is frequently cited in scientific studies and other publications dealing with aging, mainly because of the rapid development of gerontology and the search for the reason for her long life. But it’s also because in the two decades since her death, not one person has exceeded that life span.

The possibility of stretching the maximum age is a real enigma given recent technological and medical advancements, and the overall increase in life expectancy. As the means of intervening with and holding back the ravages of age increase, scientists are now asking whether our natural genetic makeup is actually limited to a maximum life span of 115 to 120 years, or whether this limit can be breached.

As you might expect, the scientific community is home to a lively debate on the subject. Last year, for example, a group of researchers from the Albert Einstein College of Medicine in New York published a paper that said the maximum life span is about 115 years.

On the other hand, other scientists are convinced that developing ways of delaying the aging process is only a matter of time, and that mankind must not accept 120 years as a limit.

The current thinking is not to provide crude medical intervention through bionic limbs, technological singularity or to create a bank of organic “spare parts” for the body, but to hold back the natural aging processes, as has already been demonstrated on animals.

Prof. Haim Cohen, head of the Molecular Mechanism of Aging Laboratory at Bar-Ilan University, Ramat Gan, is one of those who believes the maximum life span can be increased by 30 percent and eventually cross the 140-year threshold (compared to 115 to 120 years today).

Cohen and his colleagues presented their arguments in a study conducted by research student Moshe Shay Ben-Haim and eight other scientists, and published in the Journals of Gerontology earlier this month.

Open gallery view Jeanne Louise Calment at her nursing home in Arles, southern France, in October 1995, when she was 120. Credit: GEORGES GOBET / ASSOCIATED PRESS

“In the past century we’ve experienced a dramatic increase in human life expectancy,” Cohen told Haaretz. “In the past 60 years, life expectancy has risen by an average of 72 percent. However, the maximum life expectancy has risen by only 8 percent.”

One explanation for this is the huge influence that reduced infant mortality has had on the average life span. This coincided with the development of science and medicine, which included important milestones such as the discovery and use of antibiotics, developing vaccinations, and higher standards of hygiene and sterilization. Life expectancy has soared from an average of 45 in 1900, 66 in 1950 and 82 in 2014.

But when it comes to maximum life expectancy, the picture is different: Though maximum life expectancy also rose, the most significant rise took place between the 1960s and ’80s, while in the last two decades it has remained quite stable. (Note that the maximum age is not measured by extreme cases such as that of Calment, but according to the “Last Survivor” index – meaning the oldest 10 percent of the population.)

“In the study, we examined whether the minor increase in maximal life expectancy means humanity has reached its maximum potential,” Cohen said. “The average rise in life expectancy stemmed mainly from medical solutions dealing directly with disease symptoms, and that increased the number of people who lived to a more advanced age.”

Until 100 years ago, dying of old age was a privilege. The new study shows that in 1900, only 30 percent of all deaths were related to age or age-related diseases, while more than half were caused by infections. From the 1950s onward, the picture changed dramatically, as infections became curable and some of the terminal diseases turned into chronic ones. Today, more than 80 percent of deaths are related to diseases that occur mostly among the elderly.

These factors certainly contributed to extending the overall life expectancy, but why is that barely reflected in the maximum life expectancy? Cohen and his colleagues say it stems from the approach that has characterized medicine. “The changes in life expectancy have so far stemmed from medical treatments developed in response to various illnesses – but there was no intervention in the basic aging mechanisms. What will happen when we deal directly with those biological mechanisms and metabolic processes responsible for aging?” asks Cohen.

He believes the maximum age can be increased by two to three decades, due to the next generation of treatments that science will develop.

To examine whether intervention in the aging processes will affect life expectancy, Cohen and his team gathered and analyzed all the studies made in the last 20 years (“There are hundreds of them,” he noted). In them, scientists succeeded in delaying the aging of organisms such as fungi, worms, flies, mice, rats and even monkeys.

“We found something interesting in all of them: The increase in the maximum age was almost identical to the rise in the average or median age, reaching up to 30 percent,” Cohen said. He believes the findings indicate that focusing on the biological and genetic causes of aging will allow for a further leap in maximal life expectancy in the future.

“Aging is a natural biological process whose basic characteristic is decreased functioning. Though the aging process looks different in various organisms, it is based on very similar mechanisms,” Cohen said. The goal is to slow down the aging process and prolong life with medicines, he added.

But even if this is theoretically possible, there are many other questions left unanswered – highlighting the complexity of trying to interfere with the aging process. One question concerns the optimal age for intervention. Various theories show how metabolic processes vital to development at an early age become aging coefficients at an older age, and their activity contributes to various age-associated diseases.

These questions are sure to preoccupy researchers for many years to come.