Nelson Mandela's noble lifework, which will be admired and remembered for years to come, may have also in part contributed to his long life, experts say.
The former South African leader, who played a lead role in ending apartheid and served as the country's first post-apartheid president between 1991 and 1997, died Thursday (Dec. 5) at age 95.
Mandela reached an old age in spite of experiencing significant adversity, including 27 years in prison.
Mandela's positive attitude, as well as the notion that he was working on behalf of his country, may have served to buffer him from physical stress and help him cope with some of this adversity, Vickie Mays, a professor of psychology at the University of California, Los Angeles, told LiveScience in July. [Why Nelson Mandela Was So Beloved]
"The mind is a very wonderful, very intricate organ in the body that is designed to help you survive," Mays said. "Having a positive attitude under a negative circumstance, and having a belief that the experience is for a greater good, is sometimes very helpful in coping with what might be some detrimental physical outcomes."
During his incarceration, Mandela may have experienced lack of proper nutrition, including a deficiency of vitamin D, a nutrient that people get from sunlight, Mays said. Insufficient vitamin D has been linked to various diseases, including heart disease and diabetes, while healthy amounts of the vitamin foster healthy bone growth and may prevent inflammation.
Mandela was also required to perform hard labor while in prison.
Despite these hardships, "we didn’t see him as being negative or talking about the years that he lost," Mays said.
"One of the lessons to learn here is: Working for, with and on behalf of others is a very noble, and maybe health-enriching experience," Mays said. She noted that Mother Teresa also had a long life, reaching age 87.
Of course genetics and other factors, including lifestyle, also play large roles in longevity and whether a person will survive into their 90s and older. A 2010 study of people ages 100 and over, known as centenarians, found that a specific set of genetic markers could predict 77-percent of the time whether someone would live to a very old age.
Another study of people living in the mountain regions of Sicily found that those who lived past the age of 100 typically followed a so-called Mediterranean diet, one that's rich in fruits, vegetables, and whole grains, and low in red meat and refined carbohydrates.
Just one in 4,400 Americans lives to age 100, according to 2010 U.S. census data.