(CNN) -- For U.S. diplomats trying to understand the goings-on in countries with no diplomatic relations with the United States, snippets of information about the health of leaders can be valuable.
The latest group of documents released by WikiLeaks included a report from an un-named informant that Ayatollah Seyed Ali Khamenei, Iran's supreme religious leader, has terminal cancer and is "expected to die in months," while another cable said that the North Korean leader's health is in question.
A July 2009 report from U.S. officials in Seoul said that Kim Jong Il's health is failing and that, "South Korean analysts believed that KJI (Kim Jong Il) was unlikely to live more than three to five years, although he seemed to be doing better lately."
Just three months later, a Chinese official told U.S. diplomats that Kim Jong Il "appeared to be in reasonably good health."
In a memo in June 2009, an official in Singapore described Kim Jong Il dismissively as a "flabby old chap." But the Chinese official who saw Kim in October of 2009 said the ailing leader "lost weight when compared to when he last saw him three years earlier."
During a two-and-a-half hour meeting, the Chinese official asked the North Korean leader if he still drank alcohol, given his reputation among the Chinese as "quite a good drinker," according to the leaked documents.
"Kim said yes," is the response noted in the cable.
The information about Khamenei's health comes from a partially redacted U.S. diplomatic cable from August 2009, in which an un-named businessman reports a discussion that one of his contacts had with former Iranian President Ali Akbar Rafsanjani, who told him that Khamenei has terminal leukemia.
Khamenei was elected Iran's Supreme Leader in July 1989, following the death of his predecessor, Ayatollah Khomeini, and currently exercises control over the Iranian regime, including Iranian President Mahmoud Ahmadinejad.
His health could impact U.S. efforts to talk with Iran.
Other WikiLeaks documents released Monday suggest that Khamenei is reportedly willing to negotiate with the United States about Iran's nuclear goals, while Ahmadinejad is not.
U.S. officials in China sent a diplomatic cable to Washington detailing conversations that their Chinese counterparts had with the Iranians. The September 2009 cable, written approximately a month after the report about Khamenei's cancer, indicates he may be interested in talking to the United States.
The cable read, in part, that "Iran was willing to make a deal with the U.S. on the nuclear issue, adding that this willingness came from the Supreme Leader, and that President Ahmadinejad was not the decision-maker on the issue."