Foods/Supplements-Vitamins: Vitamin C - Oral

This is the other half of the vitamin C topic. (aka ascorbic acid; ascorbate)

Oral vitamin C from food or supplements is mostly not associated with reduced PCa risk. Studies mostly looked at vitamin C intake & the risk of a future PCa diagnosis.

Is there benefit after diagnosis? The vitamin C gurus who promote high-dose IVC say no.

SOME EFFECT on risk:

[Pos1] 2009 - Italy:

"for vitamin C the inverse association was of borderline statistical significance (OR = 0.86 ...)."

[Pos2] 2005 - U.S.

"Compared with men in the lowest quartile of intake, reduced risks were observed for men in the highest quartile of intake of vitamin C (OR = 0.49 ...)"

NO EFFECT on risk:

[Neg1] The Physicians' Health Study II Randomized Controlled Trial (2009)

"In this large, long-term trial of male physicians, neither vitamin E nor C supplementation reduced the risk of prostate or total cancer."

[Neg2] A 2006 U.S. study:

"Dietary and supplemental vitamin C intakes were not associated with a reduced risk of prostate cancer."

[Neg3] A 2005 U.S. study:

"The median plasma concentration of vitamin C for the cohort was 1.17 mg/dL, which is in the normal to high range for older men."

"The age-adjusted relative risk of prostate cancer for the highest quartile (median = 1.47 mg/dL ...) compared with the lowest quartile (median = 0.83 mg/dL ...) of plasma vitamin C concentration was 1.31" (!)

[Neg4] A 2003 U.S. study:

"In both cohorts, cases and controls had similar concentrations of alpha-carotene, beta-carotene, total carotene, beta-cryptoxanthin, lutein, lycopene, retinol, and ascorbic acid"

[Neg5] A 2002 Dutch study:

"For intake of retinol, vitamins C and E and other carotenoids (alpha-carotene, beta-carotene, lycopene, and lutein/zeaxanthin) no effect on overall prostate cancer risk was found."

[Neg6] A 2000 Swiss study found no benefit & reported:

"Increased cancer mortality risks associated with low plasma cholesterol were not explained by the confounding effect of antioxidant vitamins, but were attributed in part to the effect of preexisting cancer."

[Neg7] A 1996 U.S. study reported:

"During the 30-year follow-up, prostate cancer developed in 132 men {of 1,899 middle-aged men}. There was no indication that consumption of beta-carotene or vitamin C was related to increased or decreased risk of prostate cancer."

[Neg8] 1996 German study.

[Neg9] 1985 Hawaii

-Patrick

[Pos1] ncbi.nlm.nih.gov/pubmed/194...

[Pos2] ncbi.nlm.nih.gov/pubmed/163...

[Neg1] jama.jamanetwork.com/articl...

[Neg2] jnci.oxfordjournals.org/con...

[Neg3] ncbi.nlm.nih.gov/pubmed/159...

[Neg4] ncbi.nlm.nih.gov/pubmed/125...

[Neg5] ncbi.nlm.nih.gov/pubmed/121...

[Neg6] ajcn.nutrition.org/content/...

[Neg7] ncbi.nlm.nih.gov/pubmed/886...

[Neg8] ncbi.nlm.nih.gov/pubmed/860...

[Neg9] ncbi.nlm.nih.gov/pubmed/383...

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