Gamma-linolenic acid, an omega-6 fatty acid, may reduce pain, tender joint count and stiffness, and is generally safe. For omega-3 polyunsaturated fatty acids (found in fish oil), a meta-analysis reported a favorable effect on pain, although confidence in the effect was considered moderate. The same review reported less inflammation but no difference in joint function. A review examined the effect of marine oil omega-3 fatty acids on pro-inflammatory eicosanoid concentrations; leukotriene4 (LTB4) was lowered in people with rheumatoid arthritis but not in those with non-autoimmune chronic diseases. (LTB4) increases vascular permeabiltity and stimulates other inflammatory substances. A third meta-analysis looked at fish consumption. The result was a weak, non-statistically significant inverse association between fish consumption and RA. A fourth review limited inclusion to trials in which people eat ≥2.7 g/day for more than three months. Use of pain relief medication was decreased, but improvements in tender or swollen joints, morning stiffness and physical function were not changed. Collectively, the current evidence is not strong enough to determine that supplementation with omega-3 fatty acids or regular consumption of fish are effective treatments for rheumatoid arthritis.