Vitamin C and The Gastrointestinal System

Gastrointestinal ulcers, erosions, and bleeding are common adverse reactions in patients subjected to therapy with non-selective non-steroidal anti-inflammatory drugs. They damage the gastric mucosa by the inhibition of protective prostaglandins on mucosal tissues. This results in microvascular injury accompanied by the activation of neutrophils and the release of oxygen radicals.113

Vitamin C was found to eliminate free radicals.114 Vitamin C is also potentially important in the prevention

of gastric cancer by scavenging nitrate and preventing the nitrosation of dietary substances by potentially carcinogenic N-nitrosoamines.115

Recommended Daily Allowances of Vitamin C

The current daily recommended dietary allowance (RDA) of vitamin C is 75 mg for women and 90 mg for men, based on the vitamin’s role as an antioxidant as well as protection from deficiency.116,117

Pharmacological doses (> 100 mg/ day) of vitamin C may reduce the risk of chronic diseases such as cancer, cardiovascular disease, and cataracts, probably through antioxidant mechanisms. The totality of the reviewed data suggests vitamin C, 100 mg/day, may be required for the optimum reduction of chronic disease risks in nonsmoking men and women.118 Several populations warrant special attention with respect to vitamin C requirements. These include patients with periodontal disease, smokers, pregnant and lactating women, and the elderly.

Patients with Periodontal Disease

Based on evidence from a recent study, it can be concluded there is a significant relationship between dietary vitamin C intake and periodontal disease after adjusting for age, gender, gingival bleeding, and tobacco consumption.16 When compared to patients taking in excess of 180 mg of dietary vitamin C daily, the odds ratios for periodontal disease were 1.30, 1.26, 1.21, and 1.16 for patients taking 0-29 mg, 30-59 mg, 60-99 mg, and 100-179 mg of vitamin C, respectively. These findings indicate there is a dose-dependent relationship between dietary vitamin C intake and periodontal disease. Therefore, patients with

periodontal disease may benefit from a dietary analysis and, when appropriate, from daily vitamin C supplementation.

Smokers

Smokers have a higher requirement for vitamin C than nonsmokers.119,120 Vitamin C concentrations in smokers are inversely related to cigarette consumption.121-124 This is most likely due to increased demand as a result of increased oxidative stress.121,122,124 In one study, vitamin C supplementation (2000 mg/day for 5 days) significantly reduced the amount of urinary F2-isoprostanes, an indicator of oxidative stress.125 The current RDA for smokers is 110 mg/day for women and 125 mg/day for men117, although it has been proposed smokers require 120 to 180 mg/day to maintain plasma vitamin C concentrations comparable to nonsmokers.125