Antioxidant intake, plasma antioxidants and oxidative stress in a randomized, controlled, parallel, Mediterranean dietary intervention study on patients with rheumatoid arthritis

BACKGROUND: Previously we have reported that patients with rheumatoid arthritis (RA) obtained a significant reduction in disease activity by adopting a Mediterranean-type diet. The present study was carried out to investigate the antioxidant intake, the plasma levels of antioxidants and a marker of oxidative stress (malondialdehyde) during the study presented earlier. METHODS: RA patients randomized to either a Mediterranean type diet (MD group; n = 26) or a control diet (CD group; n = 25) were compared during a three month dietary intervention study. Their antioxidant intake was assessed by means of diet history interviews and their intake of antioxidant-rich foods by a self-administered questionnaire. The plasma levels of retinol, antioxidants (α- and γ-tocopherol, β-carotene, lycopene, vitamin C and uric acid) and urinary malondialdehyde (MDA), a marker for oxidative stress, were determined using high performance liquid chromatography. The Student's t-test for independent samples and paired samples were used to test differences between and within groups. For variables with skewed distributions Mann-Whitney U-test and Wilcoxon signed ranks test were performed. To evaluate associations between dietary intake of antioxidants, as well as between disease activity, MDA and antioxidants we used Pearson's product moment correlation or Spearman's rank correlation. RESULTS: The MD group had significantly higher intake frequencies of antioxidant-rich foods, and also higher intakes of vitamin C (p = 0.014), vitamin E (p = 0.007) and selenium (p = 0.004), and a lower intake of retinol (p = 0.049), compared to the CD group. However, the difference between the groups regarding vitamin C intake was not significant when under- and over-repoters were excluded (p = 0.066). There were no changes in urine MDA or in the plasma levels of antioxidants (after p-lipid adjustments of the tocopherol results), from baseline to the end of the study. The levels of retinol, vitamin C and uric acid were negatively correlated to disease activity variables. No correlation was found between antioxidant intake and the plasma levels of antioxidants. CONCLUSIONS: Despite an increase in reported consumption of antioxidant-rich foods during the Mediterranean diet intervention, the levels of plasma antioxidants and urine MDA did not change. However, the plasma levels of vitamin C, retinol and uric acid were inversely correlated to variables related to RA disease activity

Weight reduction is not a major reason for improvement in rheumatoid arthritis from lacto-vegetarian, vegan or Mediterranean diets

OBJECTIVES: Several investigators have reported that clinical improvements of patients with rheumatoid arthritis (RA), from participating in therapeutic diet intervention studies, have been accompanied by loss of body weight. This has raised the question whether weight reduction per se can improve RA. In order to test this hypothesis, three previously conducted diet intervention studies, comprising 95 patients with RA, were pooled. Together with Age, Gender, and Disease Duration, change during the test period in body weight, characterised dichotomously as reduction or no reduction (dichoΔBody Weight), as well as Diet (dichotomously as ordinary diet or test diet), were the independent variables. Dependent variables were the difference (Δ) from baseline to conclusion of the study in five different disease outcome measures. ΔESR and ΔPain Score were both characterised numerically and dichotomously (improvement or no improvement). ΔAcute Phase Response, ΔPhysical Function, and ΔTender Joint Count were characterised dichotomously only. Multiple logistic regression was used to analyse associations between the independent and the disease outcome variables. RESULTS: Statistically significant correlations were found between Diet and three disease outcome variables i.e. ΔAcute-Phase Response, ΔPain Score, and ΔPhysical Function. Δ Body Weight was univariately only correlated to ΔAcute-Phase Response but not significant when diet was taken into account. CONCLUSION: Body weight reduction did not significantly contribute to the improvement in rheumatoid arthritis when eating lacto-vegetarian, vegan or Mediterranean diets

Fat intake and composition of fatty acids in serum phospholipids in a randomized, controlled, Mediterranean dietary intervention study on patients with rheumatoid arthritis

Abstract Background We have previously reported that rheumatoid arthritis patients, who adopted a modified Cretan Mediterranean diet, obtained a reduction in disease activity and an improvement in physical function and vitality. This shift in diet is likely to result in an altered intake of fatty acids. Therefore, the objective of the present study was to examine the dietary intake of fatty acids, as well as the fatty acid profile in serum phospholipids, during the dietary intervention study presented earlier. Results From baseline to the end of the study, changes in the reported consumption of various food groups were observed in the Mediterranean diet group. The change in diet resulted in a number of differences between the Mediterranean diet group and the control diet group regarding the fatty acid intake. For instance, a lower ratio of n-6 to n-3 fatty acids was observed in the Mediterranean diet group, both assessed by diet history interviews (dietary intake) and measured in serum phospholipids. Moreover, the patients in the Mediterranean diet group that showed a moderate or better clinical improvement during the study (diet responders), had a higher reported intake of n-3 fatty acids and a lower ratio of n-6 to n-3 fatty acids compared to the patients with minor or no improvement. Also the fatty acid profile in serum phospholipids differed in part between the diet responders and the diet non-responders. Conclusion The changes in the fatty acid profile, indicated both by dietary assessments and through fatty acids in s-phospholipids may, at least in part, explain the beneficial effects of the Cretan Mediterranean diet that we have presented earlier.</p