WASHINGTON (Reuters) - The wife of a prominent Chinese dissident appealed to U.S. President Barack Obama on Tuesday to make a public call for her husband to be allowed to travel to the United States, saying he was in "alarmingly poor health" and needed medical treatment.

Human rights lawyer Gao Zhisheng was released from jail in August after three years in prison, but remains under house arrest in China. His family and human rights groups say he was physically and psychologically abused by prison authorities.

"Gao Zhisheng is now in alarmingly poor health," his wife, Geng He, who has political asylum in the United States and lives in San Francisco with their children, told a news briefing in Washington.

She said that, while her husband was recovering and learning to speak again, he was suffering the effects of severe lack of nutrition, low blood sugar and had a cyst on his gall bladder.

She said his weight had fallen from 79 kg before his incarceration to 62 kg and he had many loose teeth. Some could "easily be pulled out by hand," she said, adding he could now only eat baby food.

Geng He appealed to Obama and U.S. Secretary of State John Kerry to make public expressions of concern. She said she had spoken to her husband two days ago and he was able to talk only with difficulty.

"He said he wants very much to come to the United States to reunite with his family and his body needs to be able to recover," she added.

Jared Genser, a lawyer from Freedom Now, which campaigns for prisoners of conscience, said the fact that Gao's family had political asylum made it "the unique responsibility of the United States to actually help and make family reunification possible."

A State Department spokeswoman said in August the United States had raised Gao's case publicly and privately with senior Chinese officials and would continue to do so. It urged Beijing to allow Gao to travel freely and be reunited with his family.

Geng He said Gao, who was originally sentenced in 2006 to three years in jail for "inciting subversion of state power," had been told by police in prison that his wish to go to the United States was "nothing but a dream, especially if the U.S. government wants you to go."

The combative rights advocate attained international publicity for his campaigning for religious freedom, particularly for members of the banned religious group Falun Gong. He had also defended underground Christians and villagers embroiled in property disputes with government officials.