Riboflavin status of adolescents in southern China. Average intake of riboflavin and clinical findings.

The average riboflavin intake of 11 200 schoolchildren, aged 12-19 years, in Guangdong Province, China, was measured. Food intake was measured by weighing, and riboflavin intake was calculated by means of food tables. The average intake of riboflavin was 0.45 mg/day. In addition, clinical observations were made in 1313 adolescents in the dietary survey. The findings were consistent with the low intake of riboflavin. The observed clinical signs of riboflavin deficiency were scrotal dermatitis (7.9% of boys), angular stomatitis (5.8% of boys, 2.7% of girls), cheilosis (8.0% of boys, 5.6% of girls) and magenta tongue (36.0% of boys, 40.8% of girls). Corneal vascularization was found only in two of the 1313 children. Scrotal lesions resolved within three to six days after the oral administration of riboflavin (15 mg/day); the resolution of tongue and lip signs progressed more slowly.