The world's oldest professor, Nanjing's most elderly male resident Zheng Ji, celebrated his 109th birthday yesterday. [Photo: CFP]

The world's oldest professor, Nanjing's most elderly male resident Zheng Ji, celebrated his 109th birthday yesterday.

Born in 1900, Professor Zheng is widely thought to be the world's most aged academic, according to the Jiangsu-based Yangtze Evening Post.

Around 100 guests attended a birthday party in his honour at Nanjing University yesterday, most of them were Zheng's students.

Zhu Changsheng, one of the organizers of the party and one of Zheng's students, told China Daily: "Professor Zheng felt very happy to have so many people come to celebrate his birthday".

Zheng told guests: "Maintaining a positive and optimistic attitude and living in an active manner are the main factors contributing to a long life." As the founder of anti-aging biochemistry in the country, Zheng is one of the most famous biochemists and nutritionists in China.

He has accumulated valuable experiences in the field of anti-aging studies.

When he was 100, Zheng published a book about maintaining good health and enjoying long life.

Zhang Youshang, a member of the Chinese Academy of Sciences who attended the party, said: "Professor Zheng insisted on doing research and normal exercises after turning 100. He set a good example for other professors in the universities. Professor Zheng's actions fully illustrate the meaning of 'life lies in motion'".

In Zheng's book, he suggests the main cause of aging is the failure of cell metabolism. Therefore, isolation from radioactive and toxic substances and a healthy lifestyle are the main anti-aging factors.

Zheng spends his daily life in a strictly scheduled way. He gets up at 5 am and goes to bed at 10 pm and has a detailed timetable of activities set each day that he follows closely.

Born into a farming family in Sichuan province 109 years ago, Zheng graduated from Dongnan University (the former name of Nanjing University) and attained his master degree and doctorate in the United States.

(China Daily May 7, 2009)