Is ginger efficient and safe in osteoarthritis?

Osteoarthritis and Cartilage Journal: According to a recent study, ginger could be, although it's modestly efficient, a better treatment option than NSAIDs (anti-inflammatory drugs like ibuprofen) judged on possible adverse effects of the latter, to treat osteoarthritis.

Ginger has been an important ingredient in Asian medicine for centuries, particularly for pain relief in musculoskeletal diseases. In Europe, ginger was listed in Galén's pharmacopoeia, and was mentioned by Plinius the Elder for medicinal use. Since then, ginger has been part of the folk medicine and popular nutraceuticals. Ginger consists of a complex combination of biologically active constituents, of which the compounds gingerols, shogoals and paradols reportedly account for the majority of its anti-inflammatory properties. However, there is variability in the compounding of ginger products. The relative composition in the extraction of ginger is determined by species of ginger, maturity of the rhizome, climate in which the plants are grown, when harvested, and preparation method of the extract.

Research has shown that ginger acts as an inhibitor of cyclooxygenase (COX), particularly the inducible form of COX (COX-2), rather than the constitutive form (COX-1). 

To understand: COX-2 selective inhibitor drugs (Celebrex, Vioxx...) are a form of non-steroidal anti-inflammatory drug (NSAID) that directly targets COX-2, an enzyme responsible for inflammation and pain

 Ginger also inhibits lipo-oxygenase, resulting in suppression in the synthesis of the inflammatory leukotrienes (The leukotrienes are a family of biologically active molecules, formed by leukocytes, mastocytoma cells, macrophages, and other tissues and cells in response to immunological and nonimmunological stimulation).. 

Various ginger compounds and extracts have been tested as anti-inflammatory agents, where the length of the side chains determines the level of effectiveness. However, a combination of ginger extracts is more effective in decreasing inflammatory mediators than an individual compound. Ginger extracts are, furthermore, found to inhibit the expression of tumor necrosis factor (TNF)-α and in one study a ginger extract was shown to be as effective an anti-inflammatory agent as betamethasone.

To understand anti-TNF effect of ginger: A TNF inhibitor is a pharmaceutical drug that suppresses response to tumor necrosis factor (TNF), which is part of the inflammatory response. TNF is involved in clinical problems associated with autoimmune disorders such as rheumatoid arthritis

 

Today the therapy for osteoarthritis (OA) is still directed towards symptoms, since no disease-modifying therapy has been established, and there is continued research into potential symptom-modifying drugs with minimal adverse reactions. Apart from ginger, several other herbal medicines and nutraceuticals have been studied as alternatives to non-steroidal anti-inflammatory drugs (NSAIDs) in the treatment of OA. Among these are Boswella serrata, avocado–soybean unsaponifiables (ASU), rosehip, passion fruit peel extract, and curcuminoids. Use of herbal medicine is, furthermore, mentioned in the latest OARSI guidelines for non-surgical management of knee OA, and a thorough evaluation of orally taken and topically applied complementary and alternative medicines in the treatment of OA is given in two systematic reviews by Long et al., and by De Silva et al..

With the growing interest in use of herbal and phytochemical products in the treatment of OA, the aim of this study was to assess the clinical evidence of efficacy and safety of oral ginger in the symptomatic treatment of OA, with an emphasis on the quality of the evidence (i.e., our confidence that the estimates of the effect are correct).

Since osteoarthritis is a chronic disease with increasing need of treatment, it is important to find a right balance between benefit and harm with long term use of any applied treatment. NSAIDs are commonly used in osteoarthritis, but serious cardio-vascular and gastro-intestinal adverse effects of this group of drugs are well-known. Ginger is, on the other hand, generally considered safe, and no serious adverse effects were seen when ginger extract was given to rats. Main complaints with ginger intake are milder stomach upset, ‘bad taste in the mouth’, and similar, which also are the mentioned adverse effects which lead to withdrawal from treatment in the included studies in this meta-analysis. 

Ginger therefore seems a better treatment option than NSAIDs judged on possible adverse effects of the latter treatment. There could though be other concerns like allergy caused by the ginger preparations, and interactions with medication.

When looking at allergic reactions caused by ginger, a study demonstrated that ginger did not produce allergic reactions tested by prick-tests. In contrast, extract from common ginger in an in vitro study showed a small, although insignificant, anti-allergenic effect⁶².

It is well-documented that ginger is an anti-coagulant, and this will be of importance in connection with patients taking drugs like warfarin. A particular important finding is the synergistic effect between ginger and nifedipine on anti-platelet aggregation⁶⁵. Since osteoarthritis patients in general are older subjects who are often overweight to obese, a subpopulation with a heart condition or high blood pressure can be expected. Recommendation on trying ginger as a therapy has therefore to take a possible interaction of ginger with the patients' other medication into account prior to recommending use of ginger.