At doses above 1000 mg/day, vitamin C
has been linked to an increased risk of kidney stones in men
due to its conversion to oxalate and excretion in urine (66).
Falls noch jemand hierüber gestolpert ist - in der verlinkten Studie ist folgendes in der section "methods" zu finden:
In 1986 (NHS I and HPFS) and 1991 (NHS II), participants were
asked to complete an FFQ that asked about the average use of more
than 130 foods and 22 beverages in the previous year. Dietary in-
formation was updated every 4 years. Validation studies have
demonstrated the reliability of the FFQ.
Intake of dietary factors
was calculated from the reported frequency of consumption of each
specified unit of food and, except for oxalate, from US Department
of Agriculture data on the content of the relevant nutrient in specified portions.
The oxalate content of most foods on the FFQ, as well
as of frequently consumed foods written in, was measured by
capillary electrophoresis as previously described.
The FFQ also
inquires about vitamin and mineral supplements. Users of multi-
vitamins and vitamin C supplements are asked to name the specific
brand and provide the amount and frequency of use. Our database
contains the composition of more than 1,000 brands of multivita-
mins and calculates the amount of vitamin C (and other vitamins and
minerals) as the frequency of intake multiplied by composition. The
same method is used for individual vitamin C supplements. For the
current analysis, we used data from the FFQ for total vitamin C
(dietary plus supplement sources) intake; alcohol intake; dietary
intake of calcium, sodium, potassium, magnesium, fructose,
oxalate, phytate, animal protein, and total fluids; and calcium
supplements. All nutrients were energy-adjusted
Es ist also wohl davon auszugehen, dass liposomales Vitamin C unabhängig zu betrachten ist.