Antioxidants are substances required by the body to prevent the damage of cells caused by unstable molecules (free radicals) [1].
Free radicals are generated within the body during the conversion of food to energy [2].
Free radicals are also responsible for causing oxidative stress, which is the trigger for cell damage [3].
Oxidative stress is known to play a role in a variety of diseases like diabetes, cancer, arthritis, etc.
Arthritis is a condition leading to joint pain, stiffness, swelling, and inflammation. Antioxidants are known to be reduced in patients with arthritis. Thus, dietary antioxidants can be vital in arthritis.
Link Between Antioxidants and Arthritis
When there is an infection in the body the phagocytes (cells that protect the body from harmful substances) activation and the reaction of the bacterial products in the body leads to an increased production of free radicals which is responsible for immune cell damage.
Free radicals are also required by the bacteria for their survival. Antioxidants protect the body from these harmful chemicals and improve immunity [4].
One of the key markers of the process of arthritis disease is oxidative stress.
The reaction between immune cells and foreign bodies leads to the production of reactive oxygen species(ROS) or free radicals that are responsible for this stress [5].
In the case of rheumatoid arthritis, the body’s immune cells fail to recognize its own cells and attacks it.
The disease progression to some extent in RA can be due to these ROS. This type of reaction is like the one that takes place in case of an infection in the body [6].
The concentration of antioxidants is reduced in the synovial fluid (fluid between the joints) of rheumatoid arthritis patients [7].
Inflamed joints result in continuous production of free radicals and this ultimately leads to the failure of the antioxidant system.
One of the research study findings has concluded that there was reduced pain, inflammation and swelling of joints in arthritis patients upon antioxidant supplementation [8].
There are numerous antioxidants which can benefit in arthritis as discussed in detail below.
15 Natural Antioxidants to Combat Arthritis
Antioxidants like, vitamin A, vitamin C, vitamin E, beta-carotene, curcumin, selenium, etc. , can combat arthritis by reducing oxidative stress and preventing cell damage caused by free radicals.
These antioxidants also reduce the symptoms of arthritis and have been proven to impart the pain-relieving effect which is comparable to that of NSAI Drugs used for arthritis pain.
1. Vitamin C
Vitamin C is required for the synthesis of collagen in the body, which is required for the repair of tissues and growth of tendons, ligaments, cartilage, blood vessels and bones [9].
In arthritis, there is an increased pressure on the bones which tends to damage the cartilage. As vitamin C is involved in the synthesis of collagen, a key component of cartilage it is essential in arthritis.
Recent studies have demonstrated the analgesic (pain relieving) properties of Vitamin C [10]. Supplementation of vitamin C has been proven to be vital in arthritis.
Arthritis is mainly managed by drugs called Non-Steroidal Anti-Inflammatory Drugs (NSAID’s).
These drugs tend to reduce the vitamin C levels therefore, intake of this antioxidant becomes necessary [11].
Dose
The recommended dose of vitamin C in arthritis patient is 500mg-1000mg per day [12]. It is best to take this antioxidant 2-3 times a day. Smoking depletes vitamin C; thus, smokers require an additional 35mg per day [13].
Precautions
Vitamin C must be taken under the supervision of a health professional. Also, consult your doctor before taking more than 1 gram of vitamin C per day.
Vitamin C might cause a diuretic effect (increased urine output) [14]. Vitamin C intake warrants adequate fluid consumption.
Vitamin C may interact with other drugs to cause an increase or decrease in its action. If one is taking other medications routinely a physician’s advice is a must before taking these supplements.
People with conditions such as diabetes, thalassemia, sickle cell anemia, etc., may have severe side effects of vitamin C. Patients with existing disease conditions must consult their physician.
What does this mean? Vitamin C has pain relieving properties and it can also replace the vitamin C lost due to use of arthritis medications.
2. Vitamin E
There is a reduced concentration of vitamin E in arthritis patients which is responsible for increased ROS and oxidative stress which damage the chondrocytes (cartilage cells).
A clinical trial involving 40 arthritis patients has confirmed that supplementation of vitamin E can benefit arthritis patients by reducing oxidative stress [15].
Animal studies have shown that Vitamin E reduces joint inflammation and destruction and provides a beneficial effect on arthritis [16] .
Dose
The recommended dose of Vitamin E in arthritis patients is 400mg or 600 International Units (IU) [17].
Precautions
Taking vitamin E supplements may cause some interaction with drugs and one such example is with the blood thinning drug warfarin, where there is an increased risk of bleeding [18].
Therefore, one must obtain medical advice prior to starting vitamin E supplements.
What does this mean? Vitamin E can benefit arthritis patients by reducing oxidative stress and preventing join destruction and inflammation.
3. Beta-Carotene
Beta-carotene is one of the pigments of carotenoids. 50% of beta-carotene is converted to vitamin A. Beta-carotene content is reduced in individuals with arthritis [19].
Beta-carotene reduces tissue damage by driving away from the free radicals that bring about tissue damage [20].
Dose
The recommended dose of beta-carotene is 6-15mg per day [21].
Precautions
High doses of oral beta-carotene can cause yellowing of the skin [22]. It is advised to take this antioxidant in combination with others to reduce the risk of any side effects [23].
The side effects of beta-carotene include allergic reactions that may cause itching and swelling [24]. Physician advice must be sought in such a case.
It must be noted that there is no conclusive evidence from clinical trials for stating the benefits of beta-carotene in arthritis.
What does this mean? Beta-carotene prevents the tissue damage and reduce oxidative stress.
4. Vitamin A
The antioxidant vitamin A not only helps maintain of eyes but, it is also necessary for the development of teeth, soft and skeletal tissues [25].
It is proven with the help of animal studies that vitamin A reduces the inflammatory mediators (chemicals causing inflammation) in arthritis [26].
In animal studies, it was observed that vitamin A reduces DNA damage caused by some drugs (eg. methotrexate) used in arthritis [27].
Dose
The recommended dose of vitamin A is 2300-3000 IU per day [28].
Precautions
Vitamin A may cause side effects like headache, dry skin, dry lips, and fatigue. It may also increase cholesterol levels in the body [29].
Vitamin A can also cause some interaction with drugs (eg. Statins, antibiotic). Vitamin A supplements more than the recommended dose must be taken under supervision.
What does this mean? Vitamin A reduces inflammation and reduces toxicity caused by the drugs used in arthritis.
5. Selenium
Selenium is an important mineral in the body that helps in maintaining the immune function of the body [30]. It can help revitalize the blood cells and increase the body’s capacity to fight infections [31].
There is evidence for the reduction of selenium in arthritis[32]. The benefits of selenium in arthritis can be due to the restoration of selenium in the body and its positive effect on the immune system.
However, more evidence is required to confirm the benefits of selenium in clinical trials to prove this effect in arthritis patients.
Dose
The recommended dose of selenium in adults is 55mcg. Although, higher doses (200mcg) have been used in humans in various studies one must not take it without appropriate guidance [33].
Precautions
Selenium use for long periods or at high doses (i.e., above 400mg) may cause toxic side effects like finger-nail loss, irritability, skin rash and fatigue.
The use of selenium is contraindicated in people with hypothyroidism and skin cancer.
There can be interactions of this mineral with other drugs (chemotherapy drugs, psychiatry medicines, etc.). It is best to consult your doctor if you are taking any other drugs routinely [34].
What does this mean? Selenium content is reduced in arthritis and supplementation may benefit in the disease. Caution and physician advice is necessary before supplementation with high dose.
6. Copper
Copper is another antioxidant that helps improve the immune system, prevent DNA damage and helps in the synthesis of collagen [35].
The copper content in arthritis patients is reduced and the drugs like steroids may also contribute to copper reduction [36] [37].
Copper has been proven to be effective in arthritis patients by a study conducted by J. Forestier. It showed better tolerance compared with gold salts [38].
Animal studies have proven the anti-arthritic benefits of copper [39]. However, strong evidence from human studies is awaited.
Dose
The recommended dose of copper in adults is 900mcg per day [40].
Precaution
Side effects of copper include nausea, stomach pain, metallic taste in the mouth, etc., It has the potential to interact with other drugs (Anti-hypertensives, birth control pills, etc.) [41].
Copper supplementation is contraindicated in Wilson’s disease (excess copper in the body). Use of this supplement must be approved by your doctor.
What does this mean? Copper is proven to be effective in arthritis. It is also shown to have anti-arthritic effects in animal studies.
7. Zinc
Zinc is a trace mineral which helps in wound healing, immune system maintenance, growth, and reproduction. In arthritis patients, there is zinc malabsorption which leads to zinc deficiency [42].
A study published in the Annals of Rheumatic Diseases stated that there is a decreased concentration of zinc in arthritis patients.
A clinical trial in arthritis patients provides evidence that it reduces joint swelling, morning stiffness and improves functionality[43].
Dose
Recommended daily dose of zinc is 8-11mg [44].
Precaution
Common side effects of Zinc are a metallic taste in the mouth, stomach upset and vomiting.
Zinc can interact with anti-hypertensive drugs and antibiotics therefore, it must be taken upon guidance.
What does this mean? Zinc is proven to reduce joint swelling, stiffness and improve functionality in arthritis.
8. CoQ10 Enzyme
The coq10 enzyme is a powerful antioxidant which promotes immune system function and reduces oxidative stress.
The benefits of CoQ10 was studied in a clinical trial including 2 groups of arthritis patients. The group which received CoQ10 supplementation had reduced inflammation-causing chemicals and decreased oxidative stress [45].
Dose
The recommended dose of CoQ10 enzyme in arthritis patients is 100mg per day.
Precaution
CoQ10 enzyme supplementation may cause occasional stomach upset.
The coq10 enzyme may reduce blood sugar in diabetes patients.
It may also interact with other drugs (Eg. chemotherapy medications). Therefore, it must be taken under the supervision of a health care professional.
What does this mean? CoQ10 enzyme reduces inflammation causing chemicals in arthritis and also contributes in the reduction of oxidative stress.
9. Curcumin
Curcumin is an antioxidant found in the spice turmeric. It reduces 2 enzymes that are responsible for inflammation [46].
A review of 8 studies (meta-analysis) conducted by James WD et. al., concluded that there was a benefit of curcumin in arthritis [47].
Curcumin has been proven vital in alleviating arthritis-related pain, swelling, stiffness and increased the physical movements [48].
Another clinical trial concluded that the effects of curcumin are known to be equivalent to that of ibuprofen [49].
Dose
The recommended dose of curcumin in arthritis patients is 1000mg per day [50].
Precautions
Curcumin is generally safe but, it may cause some side effects such as stomach ache, hair loss, increase heart rate, etc. if doses higher than 1200mg per day is taken [51].
What does this mean? Curcumin has been proven to be instrumental in the reduction of arthritis symptoms and its pain relieving effect is comparable to that of ibuprofen.
10. Lycopene
Lycopene is an antioxidant present in tomatoes, grapefruit, watermelon, and algae. Clinical trials in healthy volunteers have shown to reduce oxidative DNA damage without any significant side effects [52].
Animal studies have shown that it has anti-inflammatory properties which resemble that of drug indomethacin [53].
Lycopene holds the potential to benefit in arthritis patients in a similar way as that of other antioxidants. However, human controlled trials in arthritis patients are lacking to prove this effect.
Dose
The recommended dose of lycopene is 30mg per day [54].
Precautions
Lycopene can interact with radiation and chemotherapy, therefore, it must not be taken by cancer patients [55].
What does this mean? Lycopene reduces oxidative stress and its pain relieving effect is similar to that for drugs used for pain relief.
11. Zeaxanthin
Zeaxanthin is a carotenoid pigment present in corn saffron etc., has reactive oxygen quenching properties that can benefit arthritis patients [56].
An Australian clinical study of antioxidants in arthritis proved that there was decreased damage to the cartilage due to zeaxanthin supplementation[57].
Dose
The recommended dose of zeaxanthin is 53mg per day [58].
Precautions
Zeaxanthin can cause a headache as a side effect [59].
What does this mean? Zeaxanthin combats arthritis by lowering oxidative stress and preventing cartilage depletion.
12. Lutein
Lutein is an antioxidant present in egg yolk which can singly bind to the free radical oxygen species and prevent oxidative damage [60].
Lutein is known to reduce inflammation and oxidative stress. These effects have been confirmed by numerous animal studies [61].
Dose
The recommended dose of lutein is 3mg per day.
Precautions
Lutein can cause a headache as a side effect [62].
What does this mean? Lutein which is found in egg yolk has unique property of singly binding to the free radicals and preventing oxidative stress.
13. Alpha Lipoic Acid
Alpha Lipoic Acid is a fat-soluble (unlike others which only act within the presence of water) antioxidant that works throughout the body [63].
It reduced inflammatory mediators in animal studies [64].
It has also demonstrated the capacity of reducing joint destruction and oxidative stress which can be of great benefit in arthritis patients [65].
In another animal study, alpha lipoic acid was associated with amelioration of methotrexate (a drug used for rheumatoid arthritis) induced toxicity [66].
Dose
The exact recommended dose is not available therefore one must consult a physician for the same [67].
Precautions
Alpha Lipoic Acid may cause insomnia, skin rash, diarrhea, and fatigue. It has the potential to interact with other medications. It can also reduce Vitamin B1 levels in the body [68].
What does this mean? Alpha lipoic acid has an anti-inflammatory effect and it also reduces the drug toxicity caused by arthritis medications.
14. Ginkgo Biloba
Ginkgo Biloba is one of the oldest tresses and it contains flavonoids and terpenoids which possess great antioxidant properties [69] .
Ginkgo biloba extract is proven to improve joint pain symptoms in a clinical trial involving arthritis subjects. It can also be inferred from animal studies that ginkgo has anti-arthritic and pain relieving actions [70].
Dose
The recommended dose of ginkgo biloba in arthritis patients is 180mg per day [71].
Precautions
The side effects of ginkgo biloba include headache, dizziness, stomach upset and skin reactions.
It can also interact with some medication as well as increase bleeding risk in patients on blood thinning drugs [72].
Gingko must not be taken by epileptic patients as it can cause seizures. Patients with diabetes must consult a health professional before taking this supplement [73].
What does this mean? Ginkgo biloba has antioxidant properties and reduces joint pain symptoms in arthritis.
15. Superoxide Dismutase
Superoxide Dismutase (SOD) is an antioxidant defense system present in wheat germ, nuts, sprouts, etc. [74] Manganese is a trace mineral which is a component of SOD that benefits in arthritis [75].
SOD has been proven to have anti-inflammatory effects in animal studies [76]. The use of SOD in severe rheumatoid arthritis showed significant amelioration of symptoms. [77]
Dose
The recommended dose of manganese is 1.8mg to 2.3mg
Precautions
Manganese rarely causes side effects like headache, liver damage, loss of appetite, etc. Manganese supplements must be taken with the advice of a physician and taking more than 10mg per day can be harmful as it causes damage to the nervous system [78].
What does this mean? SOD is known to have remarkable antioxidant properties along with anti-inflammatory and symptom relief effects in arthritis.
Conclusion
Antioxidants reduce immune cell damage caused by free radicals. This type of damage is a common feature in arthritis.
Various studies in humans, as well as animals, have demonstrated the beneficial effects of antioxidants like vitamin C, A, E, beta-carotene, superoxide dismutase, curcumin, CoQ10 enzyme, etc.,
The supplementation of antioxidants can benefit in reducing the symptoms of arthritis-like joint pain, swelling, and stiffness along with a reduction in inflammation.
Although, there is a good amount of evidence for benefit of some antioxidants in arthritis some others have not yet been studied thoroughly in human clinical trials.
The use of these antioxidant supplements may cause some side effects. There is also a chance interaction of most of these antioxidants with other drugs, therefore, health professional’s advice is warranted prior supplementation