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Osteoarthritis is a debilitating joint disease that mostly impacts the elderly, but it also can significantly affect working adults. The absolute cause of osteoarthritis is still unknown. It seems that genetic factors account for half of the development of osteoarthritis, while environmental factors account for the other half. The most influential environmental factor seems to be body mass index (BMI); this is particularly true for knee osteoarthritis. It has been suggested that the influence of BMI is due to diet. Oxidants, pathologic changes that cause damage to the body, have been shown to damage cartilage. The Framingham Study has shown protective effects of vitamin D, vitamin C, vitamin E, and beta carotene against osteoarthritis.
Williams et al. in England examined if patterns of food intake were associated with current osteoarthritis (hip, hand, or knee) in a large cohort of female twins. Food intake was evaluated by the 131-item food frequency questionnaire (FFQ), which was broken into the categories of fruit and vegetable, high alcohol, traditional English, dieting, and low meat. Nutrient intake from the FFQ was analyzed using an established nutrient database. BMI was calculated, and participants completed lifestyle questionnaire, which included questions about physical activity. Presence of osteoarthritis was determined by radiological assessments. The researchers also conducted an in vitro (outside of the body) analysis to examine the effects of bioactive compounds from allium vegetables (vegetables from the onion family, such as garlic and leeks) on the joints.
14.1% of the twins in the study population had hip osteoarthritis, 27.8% had knee osteoarthritis, and 58% had hand osteoarthritis. The average BMI was 25.6 kg/m2, which showed that the study population in general was not obese. Williams et al. found that the fruit and vegetable category had a statistically significant protective effect against hip osteoarthritis. The fruit and vegetable category included fruit, allium vegetables, and cruciferous vegetables (vegetables from the cabbage family, such as broccoli and Brussels sprouts). Intake of alliums and non-citrus fruits individually had statistically significant protective effects against hip osteoarthritis. The in vitro analysis showed that the bioactive compounds of diallyl disulphide and diallyl sulphide from alliums suppressed the mechanisms associated with joint damage and inflammation.
Williams et al. concluded that fruits and vegetables, particularly those from the allium family, provide a protective effect against hip osteoarthritis. This finding suggests that vegetables from the allium family could be used as an early disease intervention in order to prevent progression of hip osteoarthritis. The researchers also noted that this finding was not applicable to knee osteoarthritis or hand osteoarthritis because osteoarthritis at different sites of the body have different genetic and environmental factors.
References
1. Williams FMK, Skinner J, Spector TD et al. Dietary garlic and hip osteoarthritis: evidence of a protective effect and putative mechanism of action. BMC Musculoskeletal Disorders. 2010;11.
2. Mosby's Medical Dictionary. Oxidative Stress. The Free Dictionary. 2009. Available at http://medical-dictionary.thefreedictionary.com/oxidative+stress.
3. Magee, E. The Super-Veggies: Cruciferous Vegetables. WebMD. April 19, 2007. Available at http://www.webmd.com/food-recipes/features/super-veggies-cruciferous-vegetables.
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