A study in the Journal of Periodonology analyzed vitamin C intake and periodontal disease indicators in 12,419 adults. Researchers found that patients who consumed less than the recommended 60 mg. per day RDA of vitamin C had a 1.5 times greater risk of developing severe gingivitis compared to patients who consumed 180 mg. per day of vitamin C or more. The connection between periodontal disease and vitamin C has been known since the late 18th century. Vitamin C is important for the maintenance of healthy connective tissue.