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Side effects
of Vitamin C
Data source:
http://en.wikipedia.org/wiki/Vitamin_c
Common side-effects
Relatively large doses of vitamin C may cause
indigestion, particularly
when taken on an empty stomach.
When
taken in large doses, vitamin C causes
diarrhea in healthy
subjects. In one trial, doses up to 6 grams of ascorbic acid
were given to 29 infants, 93 children of preschool and school
age, and 20 adults for more than 1400 days. With the higher
doses, toxic manifestations were observed in five adults and
four infants. The signs and symptoms in adults were nausea,
vomiting, diarrhea, flushing of the face, headache, fatigue and
disturbed sleep. The main toxic reactions in the infants were
skin rashes.[86]
On the other hand, Cathcart has demonstrated that sick patients,
with influenza and cancer for example, do not suffer any adverse
effects whatsoever until the dosage is raised to fairly high
levels such as 100 grams or higher.[87]
Possible side-effects
As
vitamin C enhances iron absorption[88],
iron poisoning can become
an issue to people with rare
iron overload disorders,
such as
haemochromatosis. A genetic
condition that results in inadequate levels of the enzyme
glucose-6-phosphate dehydrogenase
(G6PD), can cause sufferers to develop
hemolytic anemia after
ingesting specific oxidizing substances, such as very large
dosages of vitamin C.[89]
For
decades, large doses of vitamin C have been speculated to
trigger
oxalate formation and
increase absorption of dietary oxalate, possibly causing
kidney stones.[90]
However, this speculation may not be justified since there is no
clear relationship between excess
ascorbic acid intake and
kidney stone formation.
[91]
In a
study conducted on rats, during the first month of pregnancy,
high doses of vitamin C may suppress the production of
progesterone from the
corpus luteum.[92]
Progesterone, necessary for the maintenance of a pregnancy, is
produced by the corpus luteum for the first few weeks, until the
placenta is developed enough to produce its own source. By
blocking this function of the corpus luteum, high doses of
vitamin C (1000 mg) are theorized to induce an early
miscarriage.
In a
group of spontaneously aborting women at the end of the first
trimester, the mean values of vitamin C were significantly
higher in the aborting group. However, the authors do state:
'This could not be interpreted as an evidence of causal
association.'[93]
However, in a previous study of 79 women with threatened,
previous spontaneous, or habitual abortion, Javert and Stander
(1943) had 91 % success with 33 patients who received vitamin C
together with bioflavinoids and vitamin K (only three
abortions), whereas all of the 46 patients who did not receive
the vitamins aborted.
[94]
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