To analyze the trend of dietary vitamin C intake and its food sources among Chinese population aged 50-79 years old in 9 provinces, from 1991 to 2009.

Data on twenty-four-hour dietary recall from China Health and Nutrition Survey (1991, 1993, 1997, 2000, 2004, 2006 and 2009) was used to identify the trends in vitamin C intake among Chinese population aged 50-79 years old.

Totally, 24,321 adults were assessed among 7 round surveys, including 11,739 males (48.3%) and 12,582 females (51.7%). From 1991 to 2009, the intake of vitamin C was reduced by 12.1 mg and 11.8 mg in rural male and female respectively; and the intake of vitamin C increased by 8.7 mg and 10.2 mg in urban males and females, respectively. Intake of vitamin C from the dark-color vegetables decreased by 15.1 mg and 13.9 mg in rural males and females, and it was increased first then decreased in both urban males and females. Vitamin C from the light-color vegetables kept stable during the 18 years. The intake of vitamin C in the southern residents aged 50-79 year-olds was significantly higher than that of the northern residents (except for 1997). The proportion that vitamin C intake reached to Chinese RNI were 19.8%-30.4% (urban males), 31.1%-43.9% (rural males), 15.9%-24.9% (urban females), and 26.4%-38.1% (rural females) respectively.

The present study indicated that the changing of vitamin C intake was different between urban and rural residents aged 50-79. The amount of vitamin C intake between urban and rural residents was gradually getting closer. However, the intake of vegetables and fruit was not sufficiency.