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TOPIC: How much calcium, Vit C is too much?

How much calcium, Vit C is too much? 11 Sep 2005 14:33 #3444

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I swear by [b:654cdc2267]Nature's Plus - Source of Life Multi-Vitamin & Mineral Supplement[/b:654cdc2267]. It's the only brand I've used for the last 4 years and find the results very satisfying. I've tried other brands of multi's over the years and have always come back to this brand.

I also take up to 2000 mg of Vitamin-C a day.

How much calcium, Vit C is too much? 11 Sep 2005 17:05 #3446

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Anthea wrote:


I also take up to 2000 mg of Vitamin-C a day.

 

Anthea, this is the upper limit on Vitamin C, according to the National Academy of Science. Daily requirement is only 75mg/day. You may want to be careful about dietary C foods you eat in addition to supplementation. If I might make this suggestion- cut down gradually the supplementation to allow room for dietary intake like fruits and vegetables high in vitamin C. That way you get the benefits of phytochemicals along with C and fiber. :D

According to newer studies, body tissue can only hold or are considered saturated at around 150mg of vitamin C a day due to the high oxidative rate. A practical daily upper intake should be more around 200mg/day.

There is lots of debate over the benefits of high dosage vitamin C. Just like other vitamins, too much can actually be pro-oxidative, accelerating harm vs. being beneficial.

Oranges or citric fruits, fruit juices, spinach, cantalope, cauliflower, brussels sprouts, green peppers, kale, strawberries, asparagus, papaya, pineapple, apples, broccoli are good sources of C.

Problems that can occur at 2,000mg of vitamin C
-Increase in kidney stones due to precipitation of uric acid in urine, this can increase with too much calcium supplementation too.
-Hyper absorption of Iron (Fe) for those who may be predisposed with hemochromatosis, thalassemia and sideroblastic anemia.
-Increased diarrhea
-Can create false negative tests for fecal occult blood and tests for glucose in the urine can be rendered invalid.
-The bioavailablity of vitamin B12 may be impaired by vitamin C in doses of 500mg or more taken with meals and up to 1 hour after the meal. Even 200mg has been shown to destory B12 in gastric juice within 30 minutes.

If you have been taking high vitamin C doses over a period of time and abruptly stop, problem with C deficiencies can occur because the body makes adjustments to accommodate the high levels.

Just like coming off of an antidepressant, it's a good idea to take some time to wean off large doses of vitamin C.

Thanks for your post! :D

How much calcium, Vit C is too much? 11 Sep 2005 22:22 #3445

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Thx for the detailed info. Debra. :) I'm aware of this research and don't entirely agree with it, with all respect.

According to my own information the correct dosage of Vit C per person is according to body weight - 15mg per pound of weight (I weigh 149 lb and am 5'11"). I'm still well within this limit. Vit-C is water-soluble, and I do drink a healthy amount of water per day, as well as maintain my diet, which includes plenty of fresh fruits and veges. I have not experienced any negative effects from this dosage of Vit C per day (I take ascorbic Vit C).

Thx again!

How much calcium, Vit C is too much? 12 Sep 2005 00:12 #3447

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Anthea,

Thanks for your reply. Like I've mentioned before, there is lots of debate on vitamin C between scientists. There are some researchers who still hold out from some of the old data from as early as the 70's. But there are some newer studies with improved laboratory technology that are more reliable in measuring toxic body levels as well as side effects. As far as water soluable vitamins go, they can have toxic effects as an example Vitamin B's we know B6 can cause nerve damage at levels above 100mgs.

Thankfully our body will make adjustments on the absorption of vitamin C, instead of the normal 89-90% rate of absorption, your body may adjust to absorbing only 10% in order to protect against pro-oxidation.

But what if you should decide to stop taking C at those levels, which many people do without knowledge of the potential consequences. Your body was used to receiving high levels and then has actually changed to only absorbing 10%. We don't know how long it will take to adjust back, but it could take as long as 3 months, but why take the risk if there's no real benefit?

I would refer you to the review the new data for Upper limits set forth by the National Academy of Sciences for yourself.

As a licensed registered dietitian it would not be prudent for me to endorse or recommend doses at that level and I hope anyone considering taking vitamin C at those levels would talk with their physican about it first.

Oh, one other possible problem with high levels of Vitamin C, it does increase estrogenic effects in the body, something women with PMS should think about.

How much calcium, Vit C is too much? 14 Sep 2005 14:19 #3448

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Thx Debra, again, you have supplied some really interesting information. :)

I've been looking for the "Upper limits set forth by the National Academy of Sciences" data and haven't been able to find any of this information. Do you have a resource I could find this info. at? I'm always open to learning new information.

As I mentioned before, I haven't experienced any negative effects on the dosage of Vit C I'm taking, but then again, it is just my own personal experience and I wouldn't suggest anyone use more Vit-C than is generally recommended.

I also understand completely your obligations as a dietician to not endorse any information that could possibly compromise people's well-being. I absolutely respect you for that. :)

Thanks again Debra, it is truly wonderful that you are making your expertise freely available to people who are in need of good reliable information on how to effectively manage their PMS/PMDD woes. As I told you when we first started corresponding - it is about time that a site like yours came into being - you are providing an invaluable service and you will always have my full support. :)

How much calcium, Vit C is too much? 14 Sep 2005 20:33 #3449

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Anthea,

I hope you can access this link, there is some free information about Vitamin C and other nutrients. It's very small, they make it that way because they want people to buy the books, but if you print it out you may be able to read it. It's pure research stuff, kind of boring, but if you can get through it, more power to ya.

I find it kinda boring, I like the reviews better, but you have to buy those too ($25-30 a paper). What I have at home is mostly in the form of text books and old research papers I've printed out over the years.

http://www.nap.edu/books/0309069351/html/58.html

How much calcium, Vit C is too much? 15 Sep 2005 12:50 #3450

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Thanks. :) Wow, that is some tiny print! LOL ... I'll have to copy and resize to read it through comfortably. The bit that I did read showed relevance for taking into consideration body-mass when it comes to dietary supplements, which of course, makes a lot of sense. I'll have to read the whole article through properly though.

How much calcium, Vit C is too much? 17 Sep 2005 16:05 #3451

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Anthea,
I was checking out the Nature's Plus vitamin.
Did you know it has 1000mgs of Vitamin C...I am sure you did.
So in actuality you take 3000mgs of Vitamin C.
Just thought I would share that info.
In my research that is too much but I am not a doc!
Marilee

How much calcium, Vit C is too much? 17 Sep 2005 19:56 #3452

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Thx Marilee -- good observation! I calculated the 1000mg in my multi - so I only take 2000mg in actuality. I have to add, I don't do this every day - only on days where I've been through some stress, had illness, etc.

How much calcium, Vit C is too much? 03 Feb 2010 00:04 #3453

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One more reason to be careful about taking too much vitamin C

Am J Clin Nutr 91: 487-493, 2010. First published November 18, 2009; doi:10.3945/ajcn.2009.28528
American Journal of Clinical Nutrition, doi:10.3945/ajcn.2009.28528
Vol. 91, No. 2, 487-493, February 2010


ORIGINAL RESEARCH COMMUNICATION
Vitamin C supplements and the risk of age-related cataract: a population-based prospective cohort study in women1 alicja.wolk@ki.se

Background: Experimental animal studies have shown adverse effects of high-dose vitamin C supplements on age-related cataract.
Objective: We examined whether vitamin C supplements ( 1000 mg) and multivitamins containing vitamin C ( 60 mg) are associated with the incidence of age-related cataract extraction in a population-based, prospective cohort of women.
Design: Our study included 24,593 women aged 49–83 y from the Swedish Mammography Cohort (follow-up from September 1997 to October 2005). We collected information on dietary supplement use and lifestyle factors with the use of a self-administrated questionnaire. Cataract extraction cases were identified by linkage to the cataract extraction registers in the geographical study area.
Results: During the 8.2 y of follow-up (184,698 person-years), we identified 2497 cataract extraction cases. The multivariable hazard ratio (HR) for vitamin C supplement users compared with that for nonusers was 1.25 (95% CI: 1.05, 1.50). The HR for the duration of >10 y of use before baseline was 1.46 (95% CI: 0.93, 2.31). The HR for the use of multivitamins containing vitamin C was 1.09 (95% CI: 0.94, 1.25). Among women aged 65 y, vitamin C supplement use increased the risk of cataract by 38% (95% CI: 12%, 69%). Vitamin C use among hormone replacement therapy users compared with that among nonusers of supplements or of hormone replacement therapy was associated with a 56% increased risk of cataract (95% CI: 20%, 102%). Vitamin C use among corticosteroid users compared with that among nonusers of supplements and corticosteroids was associated with an HR of 1.97 (95% CI: 1.35, 2.88).
Conclusion: Our results indicate that the use of vitamin C supplements may be associated with higher risk of age-related cataract among women.
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