Incorporation of n-3 PUFA and γ-linolenic acid in blood lipids and red blood cell lipids together with their influence on disease activity in patients with chronic inflammatory arthritis - a randomized controlled human intervention trial

Background and aim: Marine n-3 fatty acids and gamma-linolenic acid both have anti-inflammatory effects and may be useful to help treat inflammatory diseases. The effects of these alone or combined were examined in patients with arthritis in a randomized controlled trial. Design: Patients with rheumatoid arthritis or psoriatic arthritis were randomized into four groups in a double-blind, placebo-controlled parallel designed study. Patients received the respective capsules (1:3.0 g n-3 LC-PUFA/d; 2: 3.2 g gamma-linolenic acid/d; 3:1.6 g n-3 LC-PUFA + 1.8 g gamma-linolenic acid/d; 4: 3.0 g olive oil) for a twelve week period. Clinical status was evaluated and blood samples were taken at the beginning and at the end of the period. Differences before and after intervention were tested with paired t-test or with Wilcoxon test for non-normal data distribution. Results: 60 patients (54 rheumatoid arthritis, 6 psoriatic arthritis) were randomised, 47 finished per protocol. In group 1, the ratio of arachidonic acid (AA)/eicosapentaenoic acid (EPA) decreased from 6.5 +/- 3.7 to 2.7 +/- 2.1 in plasma lipids and from 25.1 +/- 10.1 to 7.2 +/- 4.7 in erythrocyte membranes (p <= 0.001). There was no significant influence on AA/EPA ratio due to interventions in group 2-4. In group 2, the intake of gamma-linolenic acid resulted in a strong rise of gamma-linolenic acid and dihomo-gamma-linolenic acid concentrations in plasma lipids, cholesteryl esters, and erythrocyte membranes. The combination of n-3 LC-PUFA and g-linolenic acid (group 3) led to an increase of gamma-linolenic acid and dihomo-gamma-linolenic acid concentrations in plasma lipids, cholesteryl esters, and erythrocyte mem-branes. This increase was only half of that in group 2. Conclusions: Incorporation of eicosanoid precursor FAs was influenced by an intake of n-3 LC-PUFA and gamma-linolenic acid suggesting a possible benefit for therapy of chronic inflammatory diseases.