*3.2. Vitamin C Uptake into Plasma*

Plasma ascorbate levels, following ingestion of either 200 mg vitamin C tablets or 1.5 Sungold kiwifruit (providing an equivalent dose of ~200 mg vitamin C), are shown in Figure 2. A statistically significant increase in plasma ascorbate was observed as early as 0.5 h post intervention (*P* = 0.008). No significant differences in the plasma time-concentration curves were observed between the two interventions (*P* = 0.645). Area under the ascorbate time-concentration curves also indicated no difference between the two interventions (Table 1). An estimate of the total increase in plasma ascorbate indicated that all of the ingested vitamin C tablet and kiwifruit-derived vitamin C accumulated in plasma over the eight-hour time course (Table 1).

**Table 1.** Area under the plasma and urinary ascorbate time-concentration curves (AUC) and total increase in plasma and urinary ascorbate. Subjects were supplemented with 200 mg vitamin C or 1.5 Sungold kiwifruit and ascorbate concentrations in plasma and urine were determined over the eight hours post intervention.


a Data represent mean ± SEM; <sup>b</sup> *P* values were determined using paired two-tailed Students *t*-test. <sup>c</sup> Total blood volumes were estimated using Nadler's formula [24].

**Figure 3.** Change in urinary ascorbate excretion following ingestion of 200 mg vitamin C (●) or 1.5 Sungold kiwifruit (○). Data represent mean ± SEM (*n* = 9). Baseline urinary ascorbate concentrations were 10 ± 4 μmol/mmol creatinine and 14 ± 3 μmol/mmol creatinine for the vitamin C and kiwifruit groups, respectively. Two way analysis of variance with Fisher pairwise multiple comparison procedure indicated a significant increase in plasma vitamin C from two hours post intervention (*P* < 0.001), as well as a significant difference between the two interventions (*P* = 0.016).
