South Korea's President Moon Jae-in has presided over some of the most tense nuclear negotiations in history, and his time in government has taken a toll on his health.

Specifically, Moon worked so hard that he lost 12 teeth due to stress, a South Korean ambassador told Business Insider Poland.

South Koreans work famously long and hard hours, and Moon's stress is shared by many others in the country, some of whom work themselves to death in a growing epidemic.

South Korea's President Moon Jae-in has presided over a historic warming of relations with its nuclear neighbor, North Korea, as well as some of the most high-stakes nuclear and military negotiations in history.

But the pressure of work life in Seoul caused him to lose many of his teeth due to stress, and that's not altogether unsurprising in high-profile jobs in South Korea.

Business Insider Poland's Rafał Tomański spoke with South Korea's ambassador in Warsaw, Mira Sun, who described the epically fraught pace of government work in Seoul.

Read more: Kim Jong Un was reportedly 'shocked' when the US pulled out a 'hidden' list of nuclear sites at the Hanoi summit

Sun, in her first interview with foreign press in 12 years, told Tomański that while she worked as the foreign press spokesperson for former South Korean President Roh Moo-hyun, she got to know Moon fairly well.

“Our terms overlapped a little over a year, and he became the chief of staff of President Roh around when I left the president’s office. When I started working at the Blue House, I was told that presidential secretary is a demanding job, both mentally and physically, and one may last about a year and a half," Said Sun, referring to the South Korean president's residence by its colloquial name.

For reference, South Korean presidential terms last five years, but Sun was told to expect she'd only last one year.

"Teeth implants is one sign of how demanding it is," Sun continued. "President Moon had 10 teeth pulled out at once while working for President Roh, and later two more as the president," she said. "I did not lose any teeth and my colleagues teased me that I apparently did not work hard enough."

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South Koreans notoriously work hard, sometimes to the point of working themselves to death. South Koreans on average work more hours per year than any country besides Mexico, clocking 2,113 work hours a year to the US's average of 1,779, according to Forbes.

Experts blame a cultural embrace of hard work and poor information about workers' rights for the lethal hours put in by South Koreans. While South Korea's economy has advanced past manufacturing, technology keeps workers plugged in around the clock.

Business Insider consulted a dentist about the impact of stress on dental health, and found out that while stress may not outright or directly cause the loss of teeth, it can contribute. Under extreme stress, people may grind their teeth, stop caring for their teeth as much, and stand at greater risk of gum disease.

All of these factors can contribute to the loss of teeth.

Read more: Japan is facing a 'death by overwork' problem — here's how companies are combatting it

South Korean President Moon Jae-in and North Korean leader Kim Jong Un attend an official welcome ceremony at Pyongyang Sunan International Airport, in Pyongyang, North Korea. Reuters/Pyeongyang Press Corps

In her interview with Tomański, Sun depicted Moon as a tireless worker who sprang to action on any task.

"In 2011, President Moon Jae-in, who at that time was a respected lawyer, was to give a first foreign press interview with Reuters— and I was asked to be his interpreter," said Sun.

"The reporter was looking for a socket to plug in his laptop computer and could not find one anywhere. In a room with several people, no one noticed that except for President Moon. Dressed in an elegant suit, he quietly got down on all fours to look for a socket. When he found one buried on the floor, he took the plug, connected the computer, brushed off his knees, sat down, and asked for the first question."