This page - Vitamin C lowers uric acid - was last reviewed or updated on 13 May 2015
Does Vitamin C lower uric acid ?
You can’t be 100% sure Vitamin C (ascorbic acid) lowers the uric acid, nor by how much.
If you can get a reduction it is likely to be under 1.0 mg/dL, but falls have been higher. For gout sufferers – they often have kidney impairment – success may hinge on how well your kidneys function and whether Vitamin C can boost their clearance of uric acid.
You can’t be sure medicines always work either, although medicines’ reliability, and the amounts they can reduce uric acid, are usually more than Vitamin C what can achieve.
But Vitamin C’s reductions are useful when they happen. If for example, a gout sufferer is dealing with a current uric acid level of 9.0 mg/dL, and needs to lower it by 3.0 to 6.0 mg/dL, then falls of the amounts - 0.35, - 0.54, - 0.78 mg/dL, or more, are clearly a helpful contribution. In some of the studies, the falls were much greater than - 0.35 to - 0.78 mg/dL. And in some, vitamin C raised uric acid, but falls were more than twice as common.
These kinds of reductions also make a useful contribution to keeping uric acid levels down when your uric acid is at around the level which controls gout attacks, thought to be 5.0 - 6.0 mg/dL and below, so helping you to avoid them. Or even preventing gout in the first place.
Can you consume enough Vitamin C to control gout ?
Could you eat your way to lowered uric acid, and control of gout, by consuming every day at least 500 mg of Vitamin C from foods and beverages? This fascinating possibility has never been studied.
But in one very large population study, nearly 50,000 and 1317 confirmed gout cases, (1) diets were analysed using a food frequency questionnaire. - a total of more than 130 foods and beverages. When Vitamin C from foods and beverages was part of the intake, (the rest of the consumed Vitamin C came from supplements), the researchers concluded that higher Vitamin C intake is associated with lower uric acid levels.
There was the lowest risk of gout with the highest Vitamin C intake, more than 1,500 mg – 1.5 grams – daily. And a higher risk with the lowest, under 250 mg daily.
You can get a detailed list of the foods highest in Vitamin C - the National Nutrient database - free - courtesy of the USDA (U.S, Dept of Agriculture) . Find it here.
Vitamin C safety
Taking Vitamin C alone should NOT be relied on unless you have a rheumatologist with experience of using it. One study, concluded it was safe for most adults at up to 2 grams/day. Dr.Atkins (Atkins diet) used higher doses than that.
But 2 grams may not be true in your case, so discuss
it with your doctor. Note these high dose Vitamin C and uric
acid studies discussed on this page were controlled scientific experiments.
Gout sufferers often have kidney impairment/failure which with mega
doses of Vitamin C, might be associated with oxalate kidney stones.
Oxalic acid is a metabolite of Vitamin C. But the Vitamin C safety study (2) said: “It is
uncertain whether this risk occurs in the general population.”
For more information about this Vitamin C safety study, it is quoted below and is a free download, courtesy of the American Journal of Clinical Nutrition.
Side effects/ adverse effects
In the meta-analysis of Vitamin C studies, no trial reported adverse effects, (maximum dose 2 grams and below); the median dose was 500 mg daily. And few reported side effects at 2 grams and below. In the small 2013 study there were no serious adverse effects at 500 mg daily for eight weeks. No one developed oxalate stones - and they were gout patients.
How long before we know the complete truth about Vitamin C and uric acid?
It’s going to take quite a number of Vitamin C and uric acid studies among gout patients to find out why there are these contradictions and hopefully get to the complete truth. Don’t expect this anytime soon.
The three mega dose studies I have quoted on this page (two of them included a few patients with gout), were conducted between 1977 – 1981 but had a relatively small number of trialists; the next Vitamin C study with gout patients included, wasn't until 2013. And to compound the challenge, note that Vitamin C’s effect on uric acid can measure differently with different measurement methods.
If you want to examine the meta-analysis itself (3) in
detail, discussed on this page, it is a free download courtesy of the Journal Arthritis Care &
Research. Click here, then
click on – “get pdf” or on "View Full Article with Supporting Information (HTML)."
(1) Choi HK, Gao X, Curham G. Vitamin C intake and the risk of gout in men: a prospective study. Archives of Internal Medicine 2009 Mar 9;169(5):502-7. doi: 10.1001/archinternmed.2008.606.
(2) Hathcock J.N, Azzi A, Blumberg J, Bray T, Dickinson A, Frei B, Jialal I, Johnston C.S, Kelly F.J, Kraemer K, Packer L, Parthasarathy S, Sies H, Traber M.G. Vitamins E and C are safe across a broad range of intakes. American Journal of Clinical Nutrition. 2005 Apr; 81(4):736-45.
(3) Stephen P. Juraschek, Edgar Miller and Allan C.Gelber Effect of oral vitamin C supplementation on serum uric acid: A meta-analysis of randomized controlled trials Arthritis Care and Research Article first published online: 29 AUG 2011 DOI: 10.1002/acr.20519
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