Vitamin C Overdose?

About consuming fruits; fresh, dried or juiced.
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Ducky
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Vitamin C Overdose?

Post by Ducky »

The recommended dietary allowance (RDA) for Vitamin C in nonsmoking adults is 75 mg per day for women and 90 mg per day for men.

In 1 liter of OJ there is 250mg. (even more if its freshly pressed)

Some of you drinking more than 1 liter a day.

"Vitamin C Overdose can cause diarrhea, gas, or stomach upset. Other side effects could be stomach cramps, nausea, and diarrhea, and an increased risk of developing kidney stones. Large amounts of Vitamin C reduce body levels of copper, an essential nutrient."

http://ezinearticles.com/?Vitamin-C-Overdose&id=144404
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RRM
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Post by RRM »

True, but particularly true for taking supplements,
because then the body has issues with sufficiently reducing the absorption rate.
As with the uptake of minerals, the uptake rate of vitamins depends
on the availability of that vitamin in your daily diet.
If you daily consume lots of vitamin c, the uptake rate is very low.
If you consume little vitamin C, the uptake rate is high.

When you occasionally consume supplements,
the body cannot properly adjust the uptake rate,
also because supplements are extremely concentrated.

Thats why people like me (who consume liters of OJ)
dont even experience the first symptoms, such as diarrhea, gas and stomach upset.
Kookaburra
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Post by Kookaburra »

Since the human body can adapt its uptake rate for the vitamins and nutrients, why is there even osteoporosis? People who consume lots of milk, will have their uptake of calcium decreased.
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Post by Kookaburra »

I was just browsing the old board and came across this quote that RRM posted.
From http://www.4.waisays.com :
"As with all minerals, the body normally absorbs just as much calcium from our food as it needs. Only about 200 mg is absorbed into the blood, on the average, whether we consume 300 mg or 700 mg calcium daily, or sometimes even when we consume up to 1200 mg supplementary calcium daily. (13) In order to absorb the right amount of calcium, absorption rate decreases when we consume more calcium.
Since only about 200 mg is absorbed no matter how high/low the consumption, how does drinking lots of milk contribute to the osteoblasts getting exhausted?
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RRM
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Post by RRM »

If you consume less than 200 mg, less will be absorbed.
If you consume more than say 1,000 mg, often more than 200 mg is consumed.
The more you consume above that level, very little, but still some extra will be absorbed.
This is because the body cannot reduce the uptake to 0.
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Post by Kookaburra »

I just realised this:

If a person(RDA: FDA Men, 19-24YR, 72kg, 160lb, 177cm, 70in) consumes 4500ml of OJ, the amount of vitamin C is 2354.43037mg as shown by the nutrient calculator while the RDA for vitamin C is only 60.00mg! Thats 39 times more! According to your logic, the absorption rate will be very low however still some extra will be taken in, and won't that lead to vitamin c overdose?
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Post by Ducky »

That's pretty scary.
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Post by Oscar »

Nobody knows exactly how much we need of a given vitamin, or how much is too much. Fat soluble vitamins are stored in fat and consequently we can handle less of those. Water soluble vitamins, like vitamin C, will be excreted by the body if not used, which is also why we need those on a more regular basis.
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Post by Kookaburra »

Isn't calcium water soluble too?
from http://jn.nutrition.org/cgi/content/full/127/8/1573S
Calcium, iron and zinc were chosen as examples of water-soluble micronutrients that many people consume at levels that do not exceed and often do not meet recommended dietary intakes.
Hence, can't I say that, in reference to the following quote:
Water soluble vitamins, like vitamin C, will be excreted by the body if not used, which is also why we need those on a more regular basis.
Calcium will be excreted by the body if not used, which is also why we need those on a more regular basis.

Please correct me if I am wrong.
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RRM
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Post by RRM »

Kookaburra wrote:Thats 39 times more! According to your logic, the absorption rate will be very low however still some extra will be taken in, and won't that lead to vitamin c overdose?
I was talking about calcium,
which is very different from vitamins.
I know about the absorption rates of calcium,
i havent investigated those of vitamin C.

I suspect that the tolerance for vitamin C is much, much higher,
as we naturally must have consumed loads of it.
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Post by RRM »

Kookaburra wrote:Isn't calcium water soluble too?
Water soluble vitamins, like vitamin C, will be excreted by the body if not used, which is also why we need those on a more regular basis.
Calcium will be excreted by the body if not used, which is also why we need those on a more regular basis.

Please correct me if I am wrong.
Ok, i will. :)
Its not just about whether its water soluble.
We cannot store vitamin C.
Calcium is stored in the bones.

Excess vitamin C is either not absorbed, or excreted.
Excess (absorbed) calcium is temporarily stored in the bones, prior to excretion,
so that when the blood calcium level goes down long after that meal,
the calcium gets released from the bones, replenishing the blood calcium level. Thus it may take a long time before you need additional calcium.
So, we need less calcium relative to vitamin C, because there is always spare (excess) calcium in the bones.
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