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Vitamin C and Cataracts

Question:
Do vitamin C supplements help prevent cataracts?

Answer:
Modest but not high doses of vitamin C from supplements may help prevent cataracts if taken for a long enough period. Get the details in the Full Answer >>

For extensive information about vitamin C supplements, see the Vitamin C Product Review.



Learn more about vitamin C and other supplements for cataracts:



Is it possible to take too much vitamin C? >>

Do any supplements help prevent or improve cataracts? >>

See other recent and popular questions >>
COMMENTS

James16537   March 5, 2018
Your website has been significantly improved with your recent new medical input.
However regarding vit C, it is actively concentrated mainly in the eye and brain, when blood levels drop. Most mammals produce the human equivalent of more than 5-10 grams a day over a 24 hour period, except primates, guinea pigs, and a bird species.
Plants can produce Vit C at 70 gm per day in direct sunlight. Knockout genetic studies of these plants failed to produce any results until the second gene was found. Both knockouts were lethal to the plant!! No gluconeogenesis. I think all of this bias comes from the historical medical dislike of Linus Pauling's work on vit C, which he took as a powder, averaging 20 gm per day. He died at the age of 92, even after all the work needed to get 2 Nobel prizes.

The medical profession even now is just beginning to raise maximal dose recommendations. Just to play it safe, I still take only 2 gm per day 4 hour controlled release, now for more than 20 years. My eyesight and hearing is unusually good.
No cataract surgery yet.

JT Flick, PhD astrophysics, (Princeton 1975)

ConsumerLab.com   March 5, 2018
Hi James - Please see the information in our CL Answer "Is is possible to take too much vitamin C" -- just to play it safe. https://www.consumerlab.com/answers/is-it-possible-to-take-too-much-vitamin-c/too_much_vitamin_c/

James16541   March 5, 2018
I agree that one can take too much vit C. The question is how much. The old IOM recs, or the newer one? In my humble opinion,the old AREDS studies also reccommended too little. Another non human example would be the 5 gms a day gorillas need at the Zoo. I think that was the St Louis Zoo. In human equivalents that would be much too much, IMHO.

Also, as far as I can recall, toxicologic cases of VitC ODs were in a few (1?) patient that already had too much oxalic acid due to a metabolic variation.

Are you aware of any documented large clinical studies where deaths or severe toxic effects occured in normal individuals taking too much slow release Vit C ? And how much?

ConsumerLab.com   March 5, 2018
Not deaths, but there are reports of negative effects with higher doses of vitamin C ranging from reduced benefit from athletic training to increased risk of cataracts. Not clear if the supplementation was with regular-release or slow release. Please see the information at https://www.consumerlab.com/reviews/vitamin-C_supplement_review/vitaminc/#cautions.


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This CL Answer initially posted on 4/14/2012. Last updated 8/8/2017.
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