The Plant-Derived Antioxidants
Many supplements used in rheumatology are antioxidants derived from herbs, spices, or other plants. When plants encounter stressors, like temperature changes or hungry insects, their secondary metabolism revs up and creates compounds with biological properties. Some of these substances influence inflammatory pathways in the human body, said Luís Silva, PhD, a medicinal chemistry researcher at the Polytechnic Institute of Guarda in Portugal. “If it is possible to reduce these kinds of anti-inflammatory processes, it is also possible that we could help people with inflammatory diseases to a good life, or a better life.”
Dr. Luís Silva
Dr. Luís Silva
Turmeric and curcumin. You might see this supplement labeled as turmeric, a golden spice in curry powder, or curcumin, an antioxidant compound known as a curcuminoid in turmeric. Curcuminoids might reduce inflammation by scavenging free radicals and inhibiting enzymes that make prostaglandins, Silva said.
Turmeric is the most popular herbal supplement for people with RA, according to Funk’s research. A study review of six publications including 539 patients in Frontiers in Immunology showed that curcumin supplements improved RA patients’ ESR, DAS, swollen joint count, and tender joint count. Turmeric could help patients with OA, too. Patients with OA who took 1000 mg/d of curcumin improved their pain and function, according to a systematic review including 12 studies and 1438 participants in the journal Nutrients. In lupus, small studies are promising but inconclusive, suggested a study review in Frontiers in Immunology.
Watch patients taking turmeric and methotrexate closely, Funk said. Both have been associated with liver problems. Some users also experience GI symptoms like diarrhea because turmeric doesn’t absorb well in the GI tract.
Milk thistle (silymarin). This flowering plant is often marketed as a liver-supporting supplement, but research also suggests promise in RA and OA. A systematic review of 12 studies in Current Rheumatology Reviews suggested that silymarin supplements might help relieve pain, reduce inflammation, and protect the cartilage matrix, synovial membrane, and cartilage cells in joints. This supplement might help via immunomodulatory, anti-inflammatory, antioxidant, and anti-apoptotic properties, the researchers said. Doses of 250-750 mg appear to be safe. Side effects such as gastroenteritis, diarrhea, bloating, and headache can occur.
Boswellia serrata. Sourced from the resin of a tree that grows in dry, mountainous regions of Asia and Africa, Boswellia serrata can help relieve joint pain and stiffness and improve joint function in OA, suggested a systematic review of seven trials involving 545 patients in BMC Complementary Medicine and Therapies. Users saw benefits when taking 100-250 mg/d for 4 weeks or more. Compounds in Boswellia serrata may inhibit 5-lipoxygenase, an enzyme involved in producing inflammatory leukotrienes. No adverse events were reported. In some studies, users have reported GI side effects.
Ginger. Ginger is a popular herbal supplement among people with RA, Funk’s research suggested. One small clinical trial involving 70 patients with RA in the journal Gene showed that taking 1500 mg/d of ginger for 12 weeks improved their DAS and boosted their expression of FoxP3 genes, which are linked with the function of regulatory T cells. A meta-analysis including three studies with 330 patients taking ginger published in the journal Nutrients suggested ginger can reduce pain and systemic inflammation in people with OA. Preclinical studies suggested phenolic compounds in this spicy root, such as gingerols, reduce inflammation through multiple mechanisms.
Funk’s research revealed wide variation in the quality of ginger supplements, reinforcing the importance of selecting an independently verified product. Research suggested a safe dose is up to 2-2.5 g/kg body weight.
Resveratrol. Found in red grapes and red wine, this compound is particularly good at blocking COX-2 enzymes, an important step in the inflammatory cascade, Silva said. “Because of their chemical structure, they have great affinity to these enzymes to lead to their inhibition,” he said. A study review of five articles including 481 patients in The European Journal of Rheumatology showed that people with OA, RA, or Takayasu arteritis who took 250-1000 mg/d of resveratrol saw improvements in pain, function, disease activity, joint swelling, and inflammation, with no side effects.
Cinnamon. This warming spice is gaining popularity as a supplement, reported the American Botanical Council. Cinnamon is often marketed as lowering blood sugar and supporting bone health. In a small study of 36 women with RA published in The Journal of the American College of Nutrition, participants who consumed 2 g/d of cinnamon powder had reduced DASs along with reduced pain and tender and swollen joint counts. Cinnamon may reduce pain by inhibiting prostaglandin and blunt inflammation by reducing the release of arachidonic acid from cell membranes, according to a study review in Frontiers in Pharmacology. GI problems and allergic reactions are among the most common side effects.
Funk, Nikiphorou, Philippou, and Silva all had no relevant disclosures.
A version of this article first appeared on Medscape.com.