He was rushed to a hospital in South Korea and had undergone emergency surgery.
Dozens of flesh-coloured parasites, one of which was 27cm (11 inches) long, were found in the man's digestive tract during life-saving operations, according to the lead surgeon, Lee Cook-jong.
Analysts believe that the issue of North Korea's nuclear and missile programs will be discussed when China's envoy, Song Tao, meets with top North Korean officials. "We have also discovered a parasite never seen in Koreans before".
Officials have said that the defecting soldier made the crossing at the Panmunjom peace village at the Joint Security Area - the heavily guarded section of the Demilitarised Zone (DMZ) where troops from the North & South face each other.
A professor at a medical school told the Review that North Korean defectors would often come to South Korea riddled with parasites, with one patient having more than 30 types of roundworms in her body.
While the contents of the defector's stomach do not necessarily reflect the wider population, his status as a soldier with an elite assignment suggests he would at least be as well nourished as an average North Korean.
South Korea's Lee also added that it could have "a very significant meaning considering the current situation".
High blood pressure is redefined as 130, not 140: United States guidelines
The changes were announced at the American Heart Association's 2017 Scientific Sessions conference in Anaheim, California. But it increases the risk for heart disease and stroke, two of the leading causes of death in the U.S.
The US leader just ended a five-nation of Asia, including a stop in Beijing, during which he called for greater diplomatic pressure to be put on North Korea to abandon its nuclear programme.
Lee Min-bok, a North Korean agriculture expert, said: "Chemical fertiliser was supplied by the state until the 1970s, but from the early 1980s, production started to decrease". Use of the corn found in his stomach, which is cheaper than rice but less popular, has increased in years when North Koreans are more anxious about harvests.
The ambassador was speaking at the North Korean mission in Geneva on Friday, as South Korea and the United States agreed in Seoul to keep co-operating towards a peaceful end to the crisis.
Since the 1990s, when government rations failed to prevent a starvation hitting the country, North Koreans have gradually turned to markets and other private means to feed themselves.
The New York Times says the Trump administration is devising a new strategy on blocking North Korea's missiles before they get far from Korean airspace.
On average, North Koreans are less nourished than their southern neighbours. A study from 2009 said pre-school children in the North were up to 13cm shorter and up to 7kg lighter than those brought up in the South.