The study, published in the BMC Musculoskeletal Disorders, highlights the possible effects of diet in protecting against osteoarthritis, suggesting a potential for using specific beneficial compounds found in garlic to develop treatments for the condition.
“Osteoarthritis is a major health issue and this exciting study shows the potential for diet to influence the course of the disease. With further work to confirm and extend these early findings, this may open up the possibility of using diet or dietary supplements in the future treatment osteoarthritis,” said Professor Ian Clark, from the University of East Anglia, a co-author of the study.
Osteoarthritis is the most common disabling joint condition affecting elderly adults, and has a significant impact on adults of working age. The cause, however, remains unclear.
Several predisposing genetic variants have been discovered, environmental risk factors that have been identified include an influence of body mass index (BMI).
But, the researchers said the precise mechanisms behind BMI’s association and of other environmental factors are uncertain.
“A role for micronutrients in both the incidence and progression of osteoarthritis, particularly at the cartilage level … Reactive oxygen species have been shown to influence both normal chondrocyte activity and cartilage damage so an important role for antioxidants is widely postulated,” said the researchers, led by Dr Frances Williams from King’s College London.
However, they said that the effects of individual dietary micronutrients in vivo, remains uncertain.
Results from the Framingham study suggested a protective effect of vitamin D on progression of knee osteoarthritis as well as protective effects of vitamin C, beta carotene and vitamin E.
Rather than attempt to look at individual nutrients, the new study investigated the patterns of food intake in relation to prevalence of osteoarthritis of the hand, hip, and knee, in a large volunteer cohort of over 1,000 healthy female twins using the food frequency questionnaire.
Trends in dietary analysis revealed a specific pattern of dietary intake, high in fruit and vegetables, showed a statistically significant inverse association with hip osteoarthritis.
The researchers reported that consumption of non-citrus fruit and alliums – such as garlic – had the strongest protective effect.
Williams and colleagues noted that diallyl disulphide – a compound found in garlic and other alliums – has been shown to repress the expression of degrading enzymes that are linked with osteoarthritis – providing a potential mechanism of action for the observed effect.
“While we don't yet know if eating garlic will lead to high levels of this component in the joint, these findings may point the way towards future treatments and prevention of hip osteoarthritis,” said Dr Williams.
The researchers added that if such results are confirmed by independent replication, then dietary intervention trials would be “a reasonable next step.”
Source: BMC Musculoskeletal Disorders
Volume 11, doi: 10.1186/1471-2474-11-280
“Dietary garlic and hip osteoarthritis: evidence of a protective effect and putative mechanism of action”
Authors: F.M.K. Williams, J. Skinner, T.D Spector, A. Cassidy, I.M. Clark, R.M. Davidson, A.J. MacGregor