Writing in the September issue of the Annals of the Rheumatic Diseases, the researchers noted that the gain from a Mediterranean-type diet intervention in patients with rheumatoid arthritis (RA) is potentially twofold.
Firstly, improvement in disease activity and secondly, reduction in cardiovascular risk - since people with RA are known to be at increased of suffering from, or dying from, cardiovascular disease.
The study involved a six-week dietary intervention in 130 female patients from different hospitals in Glasgow, UK. Participants were aged between 30 and 70, and had suffered from RA for eight years.
The intervention group attended weekly two-hour sessions for six weeks, including cooking classes, and also received written dietary information. The control group were given written dietary information only.
Both groups completed food frequency questionnaires (FFQs), and clinical and laboratory measures were assessed at baseline, 3 and 6 months.
According to the researchers, led by G McKellar from the Centre for Rheumatic Diseases, Glasgow Royal Infirmary, significant benefit was shown in the intervention group compared with controls for patient global assessment at 6 months, pain score at 3 and 6 months, early morning stiffness at 6 months and Health Assessment Questionnaire score at 3 months.
Analysis of the FFQs showed significant increases in weekly total fruit, vegetable and legume consumption and improvement in the ratio of monounsaturated:saturated fat intake and systolic blood pressure in the intervention group only.
The Med diet is rich in cereals, wine, fruits, nuts, legumes and whole grains, fish and olive oil. Its main nutritional components include beta-carotene, vitamins A, C and E, tocopherols, polyphenols, and essential minerals.
"In this study we sought to assess whether we could modify dietary lifestyle, disease activity and cardiovascular risk in female patients with RA living in areas of social deprivation by introducing them to a Mediterranean-type diet," wrote the researchers.
"This study shows that this intervention was achievable and well received by patients. Intake of fruit, vegetables and legumes increased significantly over 3 months in the intervention group and the use of monounsaturated compared with saturated fats improved."
However, the researchers said they did not find a significant improvement in the intake of the antioxidant vitamins A, C and E, but suggested that this may have been because the FFQ was not sufficiently sensitive to detect changes in the actual nutrient intake.
The Mediterranean diet has also been linked to reducing the risk for heart disease. In this study, the scientists wanted to ascertain whether they could modify the higher tendency in patients with RA of being at risk for cardiovascular disease through diet.
Following the study period, the intervention group were found on average to have lost weight (median 0.9 kg over the 6 month period), whereas the control group showed a weight gain (median 3 kg). However, the researchers said this difference was not statistically significant. They also said they noticed a small, but insignificant reduction in systolic blood pressure in the intervention group.
"This study has shown that female patients with RA following a Mediterranean-type diet derive modest benefits across a range of areas, suggesting that this type of intervention may be a useful therapeutic adjunct to conventional DMARDs, feasible in routine clinical practice and popular with patients," concluded the researchers.
Source: Annals of the Rheumatic Diseases; September 2007; 2007;66:1239-1243. doi: 10.1136/ard.2006.065151
Authors: G McKellar, E Morrison, A McEntegart, R Hampson, A Tierney, G Mackle, J Scoular, J A Scott, H A Capell