Eating vitamin C prevents scurvy . Today scurvy is known to be caused by a nutritional deficiency , but until the isolation of vitamin C and its direct link to scurvy in 1932 , numerous theories and treatments were proposed , often on little or no experimental data . This inconsistency is attributed to the lack of vitamin C as a distinct concept , the varying vitamin C content of different foods ( notably present in fresh citrus , watercress , and organ meat ) , and how vitamin C can be destroyed by exposure to air and copper .