*2.1.4 Body pool of Vitamin C*

Kallner *et al*. [25] had estimated the total body pool of vitamin C to be 2 mg/100 g body weight (excluding the amount in cells and tissues). Under normal, non-smoking conditions, the daily turnover is expected to be replaced continuously by dietary intake. Hence, as the daily metabolic loss (2.9%) and urinary loss (25%) increases [7], the RDA also increases to maintain the total body pool. This is the basis for setting the RDA for vitamin C by some important organizations like the World Health Organization.

Doses of vitamin C ≥ 250 mg/day can increase the body pool to the plasma level (40-60 μmol) necessary to maintain optimal health [26]. With adequate dietary intake, vitamin C supplementation above 400 mg/day often reach a saturated level in which the sodium-dependent vitamin C transporter can no longer permit entry of more vitamin C into the plasma [26]. This leads to increased renal excretion. Therefore, the optimal dose needed to saturate the plasma and blood corpuscles apart from the erythrocytes is 200–400 mg/day [26]. A review by the Nobel Prize winner Linus Pauling [27] had much earlier suggested 250–4000 mg/day as the daily intake of vitamin C to make allowance for saturation and restoration of depleted stores.
