High-dose Vitamin C May Worsen Arthritis 37603

High-dose Vitamin C May Worsen Arthritis

DURHAM, N.C.--Vitamin C has been associated with the slowing ofosteoarthritis (OA) progression in animal and human studies (Matrix Biol, 21,2:175-84, 2002); however, a recent in vivo animal study suggests high-dosevitamin C may actually make OA worse (Arthritis Rheum, 50, 6:1822-31,2004; www.rheumatology.org/publications/ar/index.asp).

Researchers from Duke University Medical Center exposed male guinea pigs withsurgically induced OA to low, medium or high doses of ascorbic acid for eightmonths; the low dose was equivalent to the minimum amount needed to preventscurvy, the medium dose was equivalent to the amount of a person consuming 200mg/d (5 fruits and vegetables daily) and the high dose was the dosage shown in aprevious guinea pig study to slow OA progression. The researchers found anassociation between ascorbic acid supplementation and increased cartilagecollagen content, but found ascorbic acid worsened the severity of spontaneousOA. They also reported active transforming growth factor beta (TGF beta;prolonged intraarticular exposure to which has been shown to cause OA-likechanges) was expressed in marginal osteophytes (small, abnormal bony outgrowths)that increased in size and number with increasing ascorbic acid intake.Researchers concluded the worsening of OA with ascorbic acid supplementation suggeststhat ascorbic acid intake should not be supplemented above the currentlyrecommended dietary allowance (90 mg/d for men and 75 mg/d for women).