SUMMARY: Results of a lifetime retrospective dietary survey showed persons in the lowest category of olive oil consumption had a two-and-one-half times greater risk of developing rheumatoid arthritis than did those in the highest category. In addition, those who ate the highest amount of cooked vegetables had a 75% lesser risk of developing RA.
ABSTRACT: Research into dietary interventions for rheumatoid arthritis (RA) has been, to date, relatively inconclusive, but a new Greek study suggests that high consumption of olive oil and cooked vegetables may protect against the disease and may even moderate its symptoms. Linos et al. at the University of Athens Medical School found that development of RA was closely correlated with a much-less-than average consumption of two common food items in the Greek diet: olive oil and cooked vegetables. Southern Mediterranean populations consume a diet very different from typical Western fare, much higher in both cooked and raw vegetables, fish and olive oil.
Control subjects without rheumatoid arthritis were matched with patients who had been diagnosed with RA, and a lifetime retrospective dietary survey was conducted for each group. Persons in the lowest category of olive oil consumption had a two-and-one-half times greater risk of developing RA than did those in the highest category. In addition, those who ate the highest amount of cooked vegetables had a 75% lesser risk of developing RA.
The most encouraging of previous RA research studies has pointed to a similar role for fish oils. Oil from deep sea fish such as tuna, herring, salmon or cod contain anti-inflammatory n-3 fatty acids. The authors propose a metabolic mechanism through which olive oil appears to protect against the development of RA and inhibit its inflammatory response. Especially in the relatively unrefined form in which it is consumed in Greece, olive oil is also rich in natural antioxidants and is metabolized to polyunsaturated form, eicosatreinoic acid, which, liken-3 fish oils, has anti-inflammatory effects. Consumption of n-3 rich deep-sea fish is low in Greek populations, whose fish diet comes mostly from the shallower waters of the Mediterranean. Hence they would be expected to get most of their polyunsaturated fatty acids by metabolism of the olive oil in their diets.
Source: Linos A et al. Dietary factors in relation to rheumatoid arthritis: a role for olive oil and cooked vegetables? Am J Clin Nutr 1999; 70: 1077-82.