摘要：Objectives . We sought to determine prevalence rates of vitamin C deficiency and depletion in the United States. Methods . We used data from the Third National Health and Nutrition Examination Survey to assess intake of dietary, supplemental, and serum vitamin C. Results . Mean intakes and serum levels of vitamin C were normal; however, vitamin C deficiency and depletion were common (occurring among 5%–17% and 13%–23% of respondents, respectively). Smokers, those who did not use supplements, and non-Hispanic Black males had elevated risks of vitamin C deficiency, while Mexican Americans had lower risks. Conclusions . Health professionals should recommend consumption of vegetables and fruits rich in vitamin C and should recommend supplementation for individuals at risk of vitamin C deficiency. Health professionals in the United States generally consider overt vitamin C deficiency, or scurvy, to be a disease of historical significance. 1 Despite numerous case studies in the recent medical literature, 2– 19 scurvy is now presumed to be an uncommon disease in developed nations, 20 and patients who present with low-grade inflammation, fatigue, limping, gum bleeding, or swollen extremities may not be screened for vitamin C deficiency. 15, 17, 21, 22 Furthermore, because the signs and symptoms of scurvy are similar to those of other conditions (e.g., vascultitis, rheumatic disorders, reduced lung function), patients with vitamin C deficiency initially may be misdiagnosed and prescribed medication without receiving proper therapy. 17, 23 In the United States, mean vitamin C intakes usually exceed the recommended dietary allowances (RDAs) of 75 and 90 mg per day for women and men, respectively. 24 Elevated mean intakes, however, mask the fact that numerous US residents underconsume vitamin C. Data from the US Department of Agriculture’s 1994 to 1996 Continuing Survey of Food Intakes by Individuals showed that 18% of US adults consumed less than 30 mg per day of vitamin C, despite an overall mean intake of 95 mg per day. 25 The data from this survey further indicated that 14% of male and 20% of female 13- to 18-year-olds consumed less than 30 mg per day of vitamin C (RDAs are 65 and 75 mg per day for girls and boys, respectively). 26 In addition to low dietary intakes, numerous reports have indicated that cigarette smokers are at increased risk of low serum vitamin C owing to the free-radical-quenching role of vitamin C (i.e., the ability to render oxidants harmless), 27– 29 and the most recent data from the 2000 Behavioral Risk Factor Surveillance System indicate that 23% of US adults smoke cigarettes. 30 At the same time, most Americans are not consuming the recommended number of servings of vegetables and fruits or taking vitamin supplements. 20, 31 Currently, the second leading cause of death in the United States is cancer; as a preventive measure, high vitamin C intakes may reduce the risk of oral, esophageal, stomach, and breast cancers. 20 Serum vitamin C levels have been assessed in international studies, 32– 34 but little is known regarding vitamin C status among American children and adults. The present study was conducted to determine the prevalence of vitamin C deficiency and depletion in the United States.
