Intervention With Long-chain n-3 Polyunsaturated Fatty Acids From Microalgae Oil in Patients With Rheumatoid Arthritis

Recent studies suggest that the daily intake of n-3 LC-PUFA (eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)) can support the therapy of chronic-inflammatory diseases and might be useful to prevent coronary heart diseases. The majority of these studies do not differentiate between the effects of EPA and DHA. The present study investigate the therapeutic potential of DHA in patients with rheumatoid arthritis.

As a precondition for participating in this study, the patients were provided information in writing and verbally form about the details of the study. Written informed consent was obtained from all volunteers. Before the beginning of the study, all patients were subject to a medical examination by their general rheumatologist. Thirty-eight patients with rheumatoid arthritis (DAS ≥ 2.4) entered the study.

The placebo-controlled, randomized double-blind cross-over study consists of two investigation periods of 10 weeks, with a ten-week washout period in between (after the washout period the intervention was crossed between the groups and the respective products were consumed for further 10 weeks).

Patients in the placebo period receive 60 g sausage, 8 g tomato spread and 30 g milk powder (= 200 mL milk beverage) daily. These products were enriched with sunflower oil (8 g/d).

In the intervention period, the products (60 g sausage, 8 g tomato spread and 30 g milk powder (= 200 mL milk beverage) were enriched with 8 g microalgae oil (Schizochytrium sp., Maris DHA oil, no. 3790, IOI, Hamburg, Germany). In this group, the daily dose of docosahexaenoic acid (DHA) amounted to 2.11 g.

Venous blood is collected at the beginning and at the end of each period.

• Disease activity was determined by sum of tender and swollen joints (68/66), joint score DAS28, ultrasound score (US-7 score), rheumascan, inflammatory markers (ESR, C reactive protein), HAQ questionnaire and further lifestyle forms

Inclusion criteria

• Patient has a diagnosis of RA (according to the ACR classification criteria, revised 2010) for at least 6 months prior to randomization.
• Patient has a moderate disease activity as defined by disease activity score DAS28 ≥ 2.4
• Patient has the ability to comprehend the full nature and purpose of the study, including possible risks and side effects, to cooperate with the investigator, to understand verbal and written instructions, and to comply with the requirements of the entire study.
• stable dosis of disease-modifying antirheumatic drugs within 4 weeks prior to randomization and presumably over the study periods (30 weeks).

Exclusion criteria

• Intra-articular corticosteroids within 4 weeks prior to randomization or blood sample taking
• Patients are permitted to receive either oral or parenteral glucocorticoids equivalent to ≤10 mg daily prednisone and nonsteroidal anti-inflammatory drug, if they have received a stable dose for at least 4 weeks prior to randomization and presumably over the study periods (30 weeks).