By Andrew M. Seaman
NEW YORK (Reuters Health) - Daily vitamin C supplements don't lower uric acid as much as drugs used to treat high levels of the acid that's responsible for gout, says a new study from New Zealand.
"It's not that the vitamin C didn't reduce the uric acid level at all, it's just so small that it wouldn't make a difference from the patients' perspectives," said Dr. Lisa Stamp, the study's lead author from the University of Otago in Christchurch.
Previous studies had found that people who eat the most vitamin C were at a decreased risk for developing gout, a form of arthritis caused by the crystallization of uric acid in joints. It's believed the vitamin increases the amount of uric acid excreted through a person's urine.
Few studies, however, have looked at whether vitamin C would lower uric acid levels in people already suffering with the pain and swelling of gout, or if it would lead to additional uric acid reductions in people who are already on medication.
For the new study, which was published in Arthritis & Rheumatism and funded by The Health Research Council of New Zealand, the researchers recruited 20 gout patients who were already on medicine and another 20 who were not.
The 20 participants who were on medication were taking allopurinol, which is marketed as Aloprim and Zyloprim. They were told to either increase their dose of the medicine or also take 500 milligrams of vitamin C supplements every day.
The 20 participants who were not already taking medication were either started on allopurinol or told to take a 500-milligram vitamin C supplement every day.
At the beginning of the eight-week study, the amount of uric acid in the participants' blood was 9 milligrams per deciliter on average. The researchers said a healthy uric acid level falls below 6.5 milligrams per deciliter.
In both cases, participants who started taking vitamin C - with or without medication - did not see a significant decrease in uric acid levels.
There was, however, a significant decrease in the uric acid levels of people who started on allopurinol - about 3 milligrams per deciliter - and in those who were on the drug but increased their doses - about a 1.6 milligrams per deciliter decrease.
"It still appears you're probably better off taking whatever uric acid lowering treatment your doctor would prescribe," Stamp said.
OBESITY AND BEER
She added that there could be a few reasons why they didn't see an association between vitamin C and decreased uric acid levels.
"It may be that just in gout patients that the effect of vitamin C would be too weak," she said.
But Dr. Tim Bongartz, a rheumatologist from the Mayo Clinic in Rochester, Minnesota, said it's difficult to make any firm conclusions from the new study, because it would take about 200 participants in each group to see a difference.
"So the results of the study don't tell you much," said Bongartz, who was not involved with the new study.
He added that even if the study could reproduce the results of past studies of people without gout, it probably wouldn't bring people's uric acid levels below the threshold of 6.5 milligrams per deciliter. But it doesn't mean medication is the only answer.
"It does not always have to be medication. There are many other measures that can help people drop uric acid levels. The most important one is in obese individuals to drop weight," Bongartz said.
Another way, according to both Bongartz and Stamp, is to cut back on alcohol - especially beer.
SOURCE: http://bit.ly/14uAxjS Arthritis & Rheumatism, online May 16, 2013.