Kazam tutaj uważają, że zwiększanie dawek witaminy C nie idzie w parze ze wzrostem żelaza w organizmie. Mniej więcej piszą to co Ty czyli
100 mg brane łącznie z żelazem poprawia jego wchłanianie ale branie 500 mg już nie powoduje już zwiększenia tej wchłanialności. Dodatkowo ponieważ witamina C dość krótko utrzymuje się w organizmie przyjmowana oddzielnie od żelaza nie pływa na jego wchłanianie:
"The enhancing effect of ascorbic acid on nonheme-iron
absorption, both as a supplement (46, 123) and in food (29, 46,
124, 125), is widely known. We found that total vitamin C intake
was not related to serum ferritin in model 1; however, when separated
into dietary and supplemental vitamin C in model 2,
dietary vitamin C was a significant positive predictor (P = 0.04),
whereas supplemental vitamin C was not. These observations
contrast with previous epidemiologic findings in 38 nonpregnant,
healthy, premenopausal women (71) in whom intake of vitamin
C supplements was positively associated with serum ferritin
concentration. However, others have also noted a significant
positive correlation between mealtime vitamin C intake and
serum ferritin but not total vitamin C intake (109). This observation
suggests that total daily vitamin C may not be the best indicator
of the influence of ascorbic acid on iron stores. Our results
also seem to suggest the importance of mealtime vitamin C,
which may be due to the following observations. First, vitamin C
has an enhancing effect only if it is ingested with meals (126).
Consequently, vitamin C taken at other times would play no role
in iron balance. Furthermore, it has been shown that the first
50–100 mg ascorbic acid provide the most marked enhancement
of iron absorption (40), additional quantities result in small
effects. In other words, if vitamin C is added to a diet normally
high in ascorbic acid, it would have a limited effect on iron nutriture
(40). The average dietary vitamin C intake in Framingham
elderly subjects who took vitamin C supplements was quite high,
164 mg, therefore, it is possible that supplemental vitamin C
taken at meals provides little additional enhancement of iron
absorption, and that taken between meals is irrelevant to iron
balance. In addition, several studies have shown that supplementation
with ³ 500 mg ascorbic acid at two to three meals every
day for 5-10 wk does not result in significant increases in iron
stores (75, 127–129).
Źródło:
http://www.ajcn.org/content/67/4/722.full.pdf