Increase of gingival hydroxyproline and proline by improvement of ascorbic acid status in man

The 4-hydroxyproline and proline content of periodontal tissue was measured in 24 adult volunteers with initially low and partially even deficient plasma vitamin C values, before and after peroral supplementation with 70 mg ascorbic acid daily for six weeks. The latter caused a statistically significant rise and normalization respectively of plasma ascorbic acid and simultaneously a statistically significant increase of the hydroxyproline and proline in periodontal tissue (p less than 0.01) but not before the plasma vitamin C level was above 0.9 mg/dl. The optimal plasma vitamin C level which was associated with the highest hydroxyproline and proline content in periodontal tissue ranged between 1.00-1.30 mg/dl corresponding to the total daily dietary ascorbic acid intake of about 100 mg.