Osteoarthritis Protection: Eat Onions and Garlic

Summary
Osteoarthritis is a very common condition that affects older people. For a long time, researchers have tried to find the exact etiology of the disease and whether food could influence its occurence. This study researched foods that were tested in the laboratory for their damaging or beneficial effects on cartilage. The study was performed on a volunteer group of 1,086 female twins. It was found that dietary intake high in fruit and vegetables resulted in lower incidences of hip osteoarthritis. Non-citrus fruits and alliums (garlic, leeks and onions) gave the strongest protection against osteoarthritis.

Introduction
The cause of osteoarthritis, a disease disabling the joints, remains unclear despite millions being affected. High body mass index has been related to osteoarthritis of the knee but the mechanisms are in doubt. Diet has always been a factor of concern in the pathology of osteoarthritis. Although certain oxidants pose cellular damage to the cartilage, the effects of individual dietary nutrients and how they influence or delay cartilage repair are still unclear. This study examined the overall dietary patterns for a more realistic assessment of osteoarthritis. The subjects considered were twins, who are easy to differentiate between dietary influences and associated lifestyle factors. For confirmation of the assessment, dietary compounds was tested on cartilage cells.

Methodology
* The twins who volunteered for the study completed a few questionnaires regarding health, lifestyle and dietary factors. The questionnaires listed 131 food items.
* X-ray films of the hand, hip or knee were used in the assessment of osteoarthritis.
* The food factors found to be associated with least incidences of osteoarthritis were tested on cartilage cells. The cell death and enzyme activity were assessed.

Results
* From the X-ray films, approximately 14, 27 and 58 percent of the twins were found to have features suggestive of osteoarthritis at the hip, knee and hand respectively.
* It was inferred that higher dietary content of fruit and vegetable (especially alliums and non-citrus fruits) resulted in a significant protective effect from osteoarthritis of the hip.
* Diallyl sulfides, the compound found in alliums (garlic, leeks and onions), had the potency to inhibit an enzyme responsible for cartilage damage.

Shortcomings
The study design, being cross-sectional, was not the best or most preferable method. This was attributed to the difficulty in determining the direction of cause and effect. A few twins experiencing pain from osteoarthritis could have modified their dietary patterns. The dietary assessment could have been biased. Most of the volunteers were female twins that were healthy, leading to mere pre-symptomatic changes on X-ray film examination.

Conclusion
This study was performed with the advantages of having twins as the subjects and the assessment of complete dietary patterns rather than individual foods. Osteoarthritis is linked with high BMIs but most other causatives are ambiguous. Prevention and early detection are pivotal in this disease. This study has shown promising results in the use of non-citrus fruits and alliums in diet and the beneficial effects they have on cartilage damage. The results shown in this study could be used to change the diet and nutraceuticals eaten by osteoarthritis patients to influence the course of the disease from very early on. Further workup on the confirmation and clinical trials would be required. Nonetheless, osteoarthritis could be possibly be contained by dietary modification. These results could be used in future public health messages by promoting pertinent food habits.

For More Information:
Dietary Garlic and Hip Osteoarthritis: Evidence of a Protective Effect and Putative Mechanism of Action
By Frances M.K. Williams; Jane Skinner; King’s College London, England and University of East Anglia, Norwich, England

*FYI Living Lab Reports Are Summaries of the Original Research.
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