The Effects of Vitamin C on Arthritis

Vitamin C (L-ascorbic acid) is a powerful antioxidant that plays essential roles in joint health and immune function that may benefit people with arthritis. A growing body of research suggests the vitamin may ease pain, reduce inflammation, and protect against cartilage damage associated with rheumatoid arthritis (RA) and osteoarthritis (OA). 

An autoimmune disease, RA is the result of an immune system malfunction where healthy cells are attacked by mistake, causing inflammation and swelling in affected joints. OA, often referred to as "wear-and-tear" arthritis, is characterized by a gradual deterioration of the joints.

Though different conditions, both result in joint pain that research suggests may benefit from adequate intake of vitamin C. Vitamin C may protect against the development and progression OA and RA for a variety of reasons:

• Vitamin C is a powerful antioxidant that fights molecules that trigger joint inflammation.
• Vitamin C serves a role as a co-factor in collagen synthesis, the main protein in joint tissue and bone.
• Vitamin C plays a role in fighting infection and may work to control inflammation linked to infection, which may trigger arthritis flares.

In addition, vitamin C appears to moderate the autoimmune response in rheumatoid arthritis and help prevent a worsening of the chronic condition. 

Reduces Inflammation

Inflammation is a primary feature of arthritis that may be mediated through adequate vitamin C intake, according to research published in 2019. The small study reported in the Journal for Vitamin and Nutrition Research found vitamin C intake is associated with reduced levels of inflammatory markers.

Investigators measured dietary antioxidant intake and blood levels of both antioxidants and inflammatory markers in 87 patients with active rheumatoid arthritis. They found an association between higher blood levels of vitamin C and lower levels of interleukin 1-beta (IL-1beta), a marker of inflammation.

The study authors concluded that antioxidant micronutrients play important roles in the reduction of inflammatory conditions in patients with RA.

Protects Cartilage

A handful of studies suggests vitamin C may prevent cartilage damage associated with osteoarthritis.

In a study performed on rats and published in the International Journal of Molecular Science, vitamin C was found to reduce cartilage degradation, lower levels of inflammatory cytokines, and prevent arthritic damage to joints.

A 2019 study published in PLOS One investigated vitamin C’s effect on bone and cartilage metabolism to discern how the nutrient may benefit people with osteoarthritis. Using cell cultures, investigators found vitamin C induced a cascade of reactions that help protect cartilage against damage.

Research in humans found similar results. A 2019 study published in the journal Arthritis Care & Research found vitamin C may protect against further knee damage in patients with osteoarthritis.

Investigators tracked dietary intake of vitamin C in 1,785 people with osteoarthritic knees and found those who consumed the highest levels of the vitamin showed significantly less damage to the cartilage compared to those with lower intakes of the antioxidant.

Slows Autoimmune Progression

Vitamin C appears to play a role in halting disease progression by short-circuiting the damaging autoimmune response, according to research published in the BMJ journal Annals of the Rheumatic Disease.

The British population-based study found that the antioxidant may prevent inflammatory polyarthritis, a type of rheumatoid arthritis that affects five or more joints, by modulating the autoimmune response.

Investigators assessed dietary intakes of fruits and vegetables in people without arthritis, then followed subjects for four years. The researchers found those with the lowest intake of vitamin C had a three-fold greater risk of developing polyarthritis than those with the highest intake.

Eases Pain

Vitamin C may also help to reduce joint pain associated with arthritis. The antioxidant's role of vitamin C in pain reduction was explored in a 2017 study published in the Journal of Translational Medicine. 

According to researchers, vitamin C possesses analgesic properties that appear to work along similar pathways as opioids. The micronutrient was found to ease pain under a wide range of conditions that include trauma, cancer, and neuralgia. 

In addition, the study authors noted that patients taking vitamin C alongside opioids for post-surgical pain required less medication for relief than those not taking the vitamin. They suggest it could be used to reduce medication intake for other conditions as well.

While the pain-relieving aspects of vitamin C need further exploration, the research shows promise for aiding people with arthritis.

How Much Vitamin C Do I Need?

Vitamin C is sold as a dietary supplement at most pharmacies and health food stores. However, the current research into the benefits of vitamin C on arthritis is based on dietary intake.

Meeting the recommended daily allowance (RDA)—90 milligrams (mg) a day for men and 75 mg a day for women—can easily be accomplished by eating a variety of fruits and vegetables.

Vitamin C is abundant in red peppers, orange juice, citrus fruits, broccoli, and spinach. In fact, one 6-ounce serving of orange juice provides more than 100% of the RDA for vitamin C.

When supplementing with vitamin C, it is important to use caution. Early research suggests taking too much vitamin C may have the opposite effect.

A 2004 study on guinea pigs found that higher doses of the micronutrient can be problematic for those with osteoarthritis. While these results have not been replicated in human studies, they indicate that supplementing above the current RDA levels is generally not recommended.

Before taking vitamin C supplements for your arthritis, review your diet and options with your healthcare provider. There is no standard recommended dose for people with arthritis, however, the maximum daily dose of vitamin C is 2,000 mg (unless otherwise instructed by your healthcare provider).

A Word From Verywell

There is no denying that vitamin C benefits everybody, whether they have arthritis or not. Therefore, it is a good idea to maintain a healthy amount of vitamin C-rich options in your diet. Talk to your healthcare provider about a vitamin supplement if you struggle to get enough of these foods.