It is clear that the vitamin C intake needed to prevent scurvy, 10 mg or even less, is very small. What is uncertain, however, is how much more than this is required to ensure good health. There is no clear link between the biochemical roles of vitamin C and scurvy. Thus, the amount of vitamin C necessary to prevent scurvy may not be equivalent to what is needed to satisfy the body's diverse enzymatic and non-enzymatic requirements.
Some investigators have reported that larger daily doses of vitamin C are beneficial in conditions apparently quite unrelated to scurvy (Irwin & Hutchins, 1976). For example, a study of vitamin C and physical working capacity showed that the subjects with the lowest serum vitamin C levels had the lowest aerobic capacity, and that an increase in serum vitamin C level was accompanied by a proportional increase in aerobic capacity, but only up to the vitamin C serum level of 0.8 mg/dl (Buzina & Suboticanec,1985). The serum vitamin C level 0.8 mg/dl corresponds to a daily dietary intake of about 80-100 mg, which is well above the FAO/WHO RDA. Where vitamin C and increased iron absorption are concerned, Hallberg et al. (1989) stated that the amount of vitamin C needed in the diet to achieve reasonable iron absorption is much higher than that required to prevent scurvy.
It has still not been established which biochemical function or functions best mirror the optimal dietary level of vitamin C. Where prevention of scurvy in emergencies is concerned, it can be agreed that food distributed to affected populations should cover the 30 mg FAO/WHO RDA.