Background: Beneficial effects of fish oil n-3 polyunsaturated fatty acids (PUFAs) have been reported in rheumatoid arthritis (RA) however, high doses of n-3 fatty acids have been associated with increased total and LDL cholesterol and impaired glucose metabolism. Cranberry products have been reported to improve markers of oxidative stress, inflammation, and the metabolic profile in patients with type 2 diabetes mellitus and with metabolic syndrome. We hypothesized that including low-energy cranberry juice on a regimen of fish oil supplementation could improve oxidative stress and attenuate the undesirable effects of fish oil in lipid and glucose metabolism in patients with RA. 

Methods: A 90-days randomized controlled trial was conducted. Patients (n = 70) were assigned to one of three groups: control (C); fish oil (FO) received 3 g of fish oil PUFAs supplementation/day; and fish oil and cranberry (FOCR) received 3 g of fish oil PUFAs and 500 mL of cranberry juice/day. 

Results: There was no difference in parameters between FO and the C. FOCR group showed decreased glucose (p = 0.0225), lipid (p = 0.0079), protein (p = 0.0063) oxidation, and Oxidative Stress Index (p = 0.0375) values compared to FO. FOCR reduced glucose values (p = 0.0104), triacylglycerol (p = 0.0065), protein oxidation (p = 0.0042) and Oxidative Stress Index (OSI) (p = 0.0053) compared to the C. Compared to baseline, FO group decreased triacylglycerol (p = 0.0374) and increased glucose (p 0.0001), whereas FOCR group decreased tri-acylglycerol (p = 0.0398) values. 

Conclusion: 500 mL/day of reduced-calorie cranberry juice in patients with RA using fish oil supplementation decreased lipid, protein oxidation and OSI. Turn on screen reader support To enable screen reader support, press Ctrl+Alt+Z To learn about keyboard shortcuts, press Ctrl+slash