By Alan R. Gaby, MD
Supplementing with vitamin C may help prevent gout by lowering blood levels of uric acid, reports Arthritis and Rheumatism (2005;52:1843-7). While a previous study showed that taking a large dose of vitamin C (8 grams per day) can lower blood levels of uric acid, this is the first study to show that a relatively modest amount (500 mg per day) has the same effect.
Uric acid is a byproduct of human metabolism that circulates in the bloodstream. When present in normal concentrations, uric acid is believed to have beneficial antioxidant effects in the body. However, when uric acid levels are elevated it may crystallize in joints or other tissues, resulting in the painful arthritic condition known as gout. A high blood level of uric acid is also believed to be a risk factor for heart disease development.
Uric acid levels can be controlled to some extent by restricting certain foods, such as refined sugar, red meat, organ meats, chicken, turkey, mackerel, seafood, beans, peas, spinach, and yeast. For people whose levels remain elevated, doctors may prescribe drugs that either inhibit the bodys uric acid production or promote its excretion in the urine. While these drugs can help prevent gout attacks, they may also cause side effects including kidney damage, vomiting, or severe skin rashes.
In the new study, 184 volunteers were randomly assigned to receive one of the following daily for two months: 500 mg of vitamin C, 400 IU of vitamin E, 500 mg of vitamin C plus 400 IU of vitamin E, or a placebo. Among those taking vitamin C, the average serum uric acid concentration decreased by approximately 10%. In contrast, uric acid levels increased slightly in those not taking vitamin C, and the difference between the two groups was statistically significant. The uric acid lowering effect of vitamin C was most pronounced among people whose initial uric acid level was above normal. Vitamin E had no effect on uric acid levels.
Vitamin C appears to reduce uric acid levels by increasing its excretion in the urine. The results of this study suggest that supplementing with moderate amounts of vitamin C might help prevent gout attacks. Whether larger doses would be more effective remains to be determined. In the 1970s, one group of researches expressed concern that high-dose vitamin C might actually trigger gout attacks by causing rapid mobilization of uric acid from the tissues. That concept arose from the observation that drugs that increase uric acid excretion will occasionally cause a gout attack. However, doctors who prescribe high-dose vitamin C have not seen this problem, and there are no published reports of vitamin C induced gout.
An expert in nutritional therapies, Chief Medical Editor Alan R. Gaby is a former professor at Bastyr University of Natural Health Sciences, where he served as the Endowed Professor of Nutrition. He is past-president of the American Holistic Medical Association and gave expert testimony to the White House Commission on Complementary and Alternative Medicine on the cost-effectiveness of nutritional supplements. Dr. Gaby has conducted nutritional seminars for physicians and has collected over 30,000 scientific papers related to the field of nutritional and natural medicine. In addition to editing and contributing to The Natural Pharmacy (Three Rivers Press, 1999), and the A-Z Guide to Drug-Herb-Vitamin Interactions (Three Rivers Press, 1999), Dr. Gaby has authored Preventing and Reversing Osteoporosis (Prima Lifestyles, 1995) and B6: The Natural Healer (Keats, 1987) and coauthored The Patient's Book of Natural Healing (Prima, 1999).