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Vitamin C

Humans do not synthesize vitamin C but require exogenous intake of ascorbic acid for the biosynthesis and hydroxylation of hormones, neurotransmitters, and mature collagen. Vitamin C is present in many fruits and vegetables, but proper food preparation is necessary to avoid degrading the vitamin C content.

The third National Health and Nutrition Examination Survey estimated that 14% of men and 10% of women in the United States have vitamin C deficiency. Vitamin C deficiency results in scurvy. Generalized symptoms of scurvy include fatigue, myalgias, arthralgias, weakness, anorexia, weight loss, and irritability. Dermatologic manifestations include follicular hyperkeratosis with perifollicular hemorrhage surrounding twisted, brittle hairs, ecchymoses, poor wound healing, and swelling in the legs. Soft-tissue or subperiosteal hemorrhage usually occurs in the legs and may cause pain so severe that affected persons are unwilling to walk. Left untreated, scurvy may result in cardiorespiratory failure and death.

Anemia occurs in 75% of patients with scurvy and is the only routine laboratory abnormality. Multifactorial causes of the anemia include blood loss into tissues or from the gastrointestinal tract, intravascular hemolysis, and coexisting folate and iron deficiencies. Vitamin C deficiency does not cause coagulation abnormalities.

The diagnosis of scurvy depends on history, physical examination, and clinical improvement after the administration of ascorbic acid. Although a low plasma vitamin C level is specific for the diagnosis of scurvy, plasma vitamin C levels quickly normalize with enteral intake of ascorbic acid and do not reflect tissue levels. Leukocytes serve as a storage pool for ascorbic acid. The measurement of ascorbic acid levels in leukocytes may be considered, although such levels may not be easily obtainable and may also be affected by dietary intake.

References

Hampl JS, Taylor CA, Johnston CS. Vita- min C deficiency and depletion in the Unit- ed States: the Third National Health and Nutrition Examination Survey, 1988 to 1994. Am J Public Health 2004;94:870-5.

Hirschmann JV, Raugi GJ. Adult scurvy. J Am Acad Dermatol 1999;41:895-906.

Reuler JB, Broudy VC, Cooney TG. Adult scurvy. JAMA 1985;253:805-807.

Wilson CW. Clinical pharmacological aspects of ascorbic acid. Ann N Y Acad Sci 1975;258:355-376.

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