Garlic May Ward off Pain in Knee Osteoarthritis

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Dehghani and colleagues¹ in Iran and Australia have discovered that garlic supplementation of 12 weeks’ duration may reduce pain in overweight or obese women with knee osteoarthritis (OA).

Obesity, pain, and osteoarthritis
Osteoarthritis (OA) is the most prevalent progressive joint disease that can lead to deformity, comorbidities, and poor quality of life. Recent research has implicated adipose tissue and adipose-derived peptides such as adipo-cytokines and tumor necrosis factor alpha (TNF-α) in OA pathogenesis.

Studies have shown that garlic may reduce the risk of cardiovascular and other inflammatory diseases. Dehghani and associates looked at the effect of garlic supplementation on serum concentrations of resistin and TNF-α in overweight or obese women with knee OA. Furthermore, they sought to determine whether garlic supplementation could alter disease complications such as pain in knee OA.

The study
The authors conducted a randomized, double-blind, placebo-controlled, parallel-design trial that included postmenopausal overweight and obese women aged 50 to 75 years with mild to moderate knee OA. Patients with other chronic diseases, allergies to garlic, smokers, those with hip OA, or in weight loss programs were excluded.

Two random groups were formed with one receiving blinded 500-mg garlic tablets two times a day for 12 weeks and the other placebo. Joint pain was assessed using a visual analogue scale, and blood was obtained for resistin and TNF assays.

Ultimately, 76 subjects completed the study (39 in the garlic group and 37 in the placebo group).

Next: the results and take-home points for clinicians.

The results
Following garlic supplementation for 12 weeks, serum concentrations of resistin were significantly decreased in the garlic group (6.41 ± 2.40 to 5.56 ± 2.16 ng/mL; P = .008). No significant changes in TNF-α concentration were observed within or between the garlic and placebo groups.

Pain scores were significantly decreased in the garlic group (6.8 ± 2 to 5.3 ± 2.3; P = .002) but not in the placebo group (6.7 ± 2.4 to 6.2 ± 2.5; P = .674). Pain scores were also significantly lower in the garlic group than in the placebo group at week 12 (5.3 ± 2.3 vs 6.2 ± 2.5; P = .043).

Take-home points
• Clinicians may counsel overweight and obese women with OA that supplementation with garlic may help reduce knee pain.

• Garlic is an inexpensive and relatively benign supplement that may reduce OA inflammation.

• While resistin levels were reduced in the garlic group, TNF-α levels were not.

• Pain relief in knee osteoarthritis may be mediated by the reduction in resistin in obese women.

• Overweight and obese women with knee OA can be encouraged that the use of garlic in their daily diets may improve joint pain with little downside.

Next: final thoughts.

Final thoughts
• It is always encouraging when therapeutic recommendations include easy-to-implement, safe, low-cost strategies.

• Garlic is so ubiquitous in everyday diet that encouraging patients with OA to include more in their cuisine may be far easier than starting them on a new drug.

• Care should be taken to limit expectations, especially since this was a small study with limited scope.

• Without measures of joint damage and progression, one can only extrapolate that garlic might reduce pain with unknown effects on cartilage loss and functional status.

References:

1. Dehghani S, Alipoor E, Salimzadeh A, et al. The effect of a garlic supplement on the pro-inflammatory adipocytokines, resistin and tumor necrosis factor-alpha, and on pain severity, in overweight or obese women with knee osteoarthritis. Phytomedicine. 2018;48:70-75. doi: 10.1016/j.phymed.2018.04.060.