“These changes occur at the molecular level and were clearly visible when we did our study, regardless of the class of molecules we were looking at,” he says.
The tests involved 108 volunteers aged between 25 and 75, who provided blood, stool and skin, mouth and nose swabs every few months for one to seven years. Thanks to this, the scientists were able to analyze 135,000 different molecules (RNA, proteins and metabolites) and microbes (bacteria, viruses and fungi that lived in the gut and on the skin of the participants). This allows the scientists to claim with such confidence that human cells do not change gradually, in chronological order. They found clusters of molecules with the greatest changes in age between 40 and 60 years.
The sharp acceleration of the aging process at age 44 seemed so unexpected to scientists that they initially attributed it to hormonal changes in women’s bodies before menopause. But further research has shown that similar changes occur in men of the same age.
