A Long-term Moderate Intervention With n-3 LC-PUFA-supplemented Dairy Products in Patients With Rheumatoid Arthritis

Recent studies suggest that n-3 LC-PUFA may improve cardiovascular and inflammatory diseases.

As a precondition for participating in this study, the subjects were provided information in writing and verbally about the details of the study. Informed consent was obtained from all volunteers. Before the beginning of the study, all participants were subject to a medical examination in the Clinic for Rheumatology (Internal Medicine III, Friedrich Schiller University, Jena). The RA was diagnosed according to the 1987 revised criteria of the American Rheumatism Association (ARA). Severity of disease activity was evaluated by using the disease activity score DAS 28.

Forty five subjects (43 f, 2 m) were randomly divided into two groups to carry out a double-blind, placebo-controlled cross-over study.

The study consisted of two investigation periods of 12 weeks, with an eight-week washout period in between. Patients received about 40 g fat daily (200 g yoghurt with 3.8% fat, 30 g cheese with about 50% fat in the dry matter, and 20-30 g butter). The milk fat was partially exchanged by special oils with high amounts of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and alpha linoleic acid (ALA). The daily dose of n-3 FA amounted to 2.4 g, consisting of 1.1 g ALA, 0.7 g EPA, 0.1 g DPA, and 0.4 g DHA. The placebo products were commercial dairy products with comparable fat contents.

Venous blood and 24h urine were collected at the beginning and at the end of each period. The DAS 28 score was assessed at the beginning and the end of each period, respectively.

Inclusion criteria

• Clear diagnosis of Rheumatoid Arthritis
• Patients receiving nonsteroidal anti-inflammatory drugs (NSAID) or corticosteroids (max. 15 mg/d) or both were eligible if dosage had been stable for at least 4 weeks before day 1 of the study and remained below this limit throughout the study
• Patients on disease-modifying antirheumatic drugs (DMARD) had to be on a constant dosage for at least 8 weeks before and throughout the study

Exclusion criteria

• Subjects with gastrointestinal or metabolic diseases, alcohol abuse, taking dietary supplements (e. g. fish oil capsules), known allergies or foodstuff indigestibility
• patient's request, serious infections, inadequate control of arthritis symptoms (over 50% increase of the number of swollen or tender joints), reinstitution of therapy with DMARD, or if patient compliance with the study protocol was doubtful.