Vitamin C does not lower uric acid levels in gout patients

May 16, 2013

Despite previous studies touting its benefit in moderating gout risk, new research reveals that vitamin C, also known ascorbic acid, does not reduce uric acid (urate) levels to a clinically significant degree in patients with established gout. Vitamin C supplementation, alone or in combination with allopurinol, appears to have a weak effect on lowering uric acid levels in gout patients according to the results published in the American College of Rheumatology (ACR) journal, Arthritis & Rheumatism.

Gout is an inflammatory that causes excruciating pain and swelling triggered by the crystallization of within the joints. Estimates from the ACR report that more than 8.3 million Americans suffer with gout. Medical evidence reports that long-term gout management requires treatment with medications that lower urate levels by inhibiting uric acid production (allopurinol) or increasing uric acid excretion (probenecid) through the kidneys.

"While current treatments are successful in reducing the amount of uric acid in the blood, there are many patients who fail to reach appropriate urate levels and need additional therapies," explains lead author, Prof. Lisa Stamp, from the University of Otago in Christchurch, New Zealand. "Vitamin supplementation is one such alternative therapy and the focus of our current study, which looked at the effects of vitamin C on urate levels in patients with gout."

The team recruited gout patients who had urate levels greater than the ACR treatment target level of 0.36 mmol/L (6 mg/100 mL). Of the 40 participants with gout, 20 patients already taking allopurinol were given an additional 500 mg dose of vitamin C daily or had the dose of allopurinol increased, while another 20 patients not already taking allopurinol were either started on allopurinol or vitamin C (500 mg/day). Researchers analyzed blood levels of vitamin C (ascorbate), creatinine and uric acid at baseline and week eight.

Study findings show that a modest vitamin C dose for eight weeks did not lower urate levels to a clinically significant degree in gout patients, but did increase ascorbate. The results differ from previous research which found that vitamin C reduced urate levels in healthy individuals without gout, but with high levels of uric acid (hyperuricemia). In fact, the Stamp et al. study found that reduction of uric acid was significantly less in gout patients taking vitamin C compared to those who started or increased their dose of .

"Though vitamin C may reduce of developing gout, our data does not support using vitamin C as a therapy to lower uric acid levels in patients with established gout," concludes Prof. Stamp. "Further investigation of the urate lowering effects of a larger dose in those with is warranted."

Explore further: Gout study offers genetic insight into 'disease of kings'

More information: "Clinically insignificant effect of supplemental vitamin C on serum urate in patients with gout; a pilot randomised controlled trial." Lisa K Stamp, John L O'Donnell, Christopher Frampton, Jill Drake, Mei Zhang and Peter T Chapman. Arthritis & Rheumatism; Published Online: May 16, 2013 (DOI: 10.1002/art.37925).

Related Stories

Gout study offers genetic insight into 'disease of kings'

December 23, 2012
Scientists have shed light on why some people are more susceptible to gout than others. A study has identified 18 new genetic variations that increase levels of uric acid in the blood, which is the main cause of the disease. ...

Clinical trial demonstrates that rilonacept significantly reduces gout flares

January 5, 2012
A phase II clinical trial found that rilonacept, an inhibitor of the protein interleukin-1 (IL-1), significantly reduced acute gout flares that occur when initiating uric acid-lowering therapy. Results of the trial—the ...

Gout guidelines arm patients and physicians with tools to fight painful disease

September 28, 2012
Gout is one of the most common forms of inflammatory arthritis, affecting nearly 4% of adult Americans. Newly approved guidelines that educate patients in effective methods to prevent gout attacks and provide physicians with ...

Eating cherries lowers risk of gout attacks by 35%

September 28, 2012
A new study found that patients with gout who consumed cherries over a two-day period showed a 35% lower risk of gout attacks compared to those who did not eat the fruit. Findings from this case-crossover study published ...

Study finds gout and hyperuricemia on the rise in the US

June 26, 2012
Researchers from Boston University School of Medicine (BUSM) have found that the incidence of gout and hyperuricemia (high uric acid levels) in the U.S. has risen significantly over the last 20 years and is associated with ...

Recommended for you

Opioids and obesity, not 'despair deaths,' raising mortality rates for white Americans

July 20, 2017
Drug-related deaths among middle-aged white men increased more than 25-fold between 1980 and 2014, with the bulk of that spike occurring since the mid-1990s when addictive prescription opioids became broadly available, according ...

Aging Americans enjoy longer life, better health when avoiding three risky behaviors

July 20, 2017
We've heard it before from our doctors and other health experts: Keep your weight down, don't smoke and cut back on the alcohol if you want to live longer.

Parents have critical role in preventing teen drinking

July 20, 2017
Fewer teenagers are drinking alcohol but more needs to be done to curb the drinking habits of Australian school students, based on the findings of the latest study by Adelaide researchers.

Fresh fish oil lowers diabetes risk in rat offspring

July 19, 2017
Fresh fish oil given to overweight pregnant rats prevented their offspring from developing a major diabetes risk factor, Auckland researchers have found.

High-dose vitamin D doesn't appear to reduce the winter sniffles for children

July 18, 2017
Giving children high doses of vitamin D doesn't appear to reduce the winter sniffles, a new study has found.

Scientists develop new supplement that can repair, rejuvenate muscles in older adults

July 18, 2017
Whey protein supplements aren't just for gym buffs according to new research from McMaster university. When taken on a regular basis, a combination of these and other ingredients in a ready-to-drink formula have been found ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

Mauricio
1 / 5 (1) May 16, 2013
one of the worst studies I ever read!

1. no blind placebo control condition
2. they did not evaluate dose dependent function. They should had have different groups with different doses: 500, 1000, 2000, 3000 milligrams.
3. 500 milligrams is a very low dose of vitamin C, regardless what the government advices. Many studies have found that vitamin c is effective at larger doses for many problems.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.