Dietary Omega-3 Fats for Treatment of Inflammatory Joint Disease: Efficacy and Utility
Section snippets
Effects of fish oil in rheumatoid arthritis and other inflammatory disorders
There have been 14 double-blind, randomized, controlled trials that examined the effects of fish oil on clinical outcomes in established rheumatoid arthritis (RA) (reviewed in Ref. [1]). Tender joint count was the most common outcome measure to have a statistically significant improvement with fish oil, compared with other outcomes. Ten of these trials were included in a meta-analysis and mega-analysis of outcomes after 12 weeks of fish oil supplementation. These analyses concluded that fish
Chemistry of omega-3 fatty acids
There can be the mistaken assumption, often created by marketers, that ω-3 fats in vegetable oils are the same as those in fish oils. The designation ω-3 applies to a class of fatty acids that have a double bond between carbon atoms 3 and 4, counted from the omega end of the carbon chain (Fig. 1). These fatty acids are essential for many functions, particularly in excitable tissues such as brain, retina, and myocardium, and because neither human beings nor fish can insert an ω-3 double bond,
Biochemical actions of omega-3 fatty acids relevant to inflammatory disorders
The lipid inflammatory mediators, prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) are products of the ω-6 20-carbon fatty acid, arachidonic acid (AA; 20:4ω-6), metabolized via the cyclooxygenase (COX) and 5-lipoxygenase (5-LOX) pathways, respectively. Hyperalgesia in response to peripheral inflammation appears to be caused by the actions of central nervous system (CNS) PGE2 newly synthesized by both induced and constitutive CNS COX-2 in concert with induced PGE synthase [13], [14], [15].
Dietary omega-6 fatty acids: excess and interactions
The use of polypharmacy in modern medical practice has brought an appreciation of the care that is needed in handling drug interactions. These can decrease or increase actions of the drug under consideration. Likewise, this is a consideration in the therapeutic use of fish oil and it is one that requires an appreciation of other unsaturated fats in the diet.
In chemical terms, ω-3 fatty acids are polyunsaturated. However, the common or marketing use of the word “polyunsaturated” for fats in
Fish oil use in a rheumatology clinic
Doses of 3 g to 5 g per day EPA plus DHA are required for an anti-inflammatory effect. Such doses can be achieved realistically only with fish oil, even though fish and ω-3 containing vegetable oils can provide a valuable contribution. Typically, 10 mL to 15 mL per day of fish oil is needed for an anti-inflammatory dose of ω-3 fats, and this can be achieved most cheaply and efficiently with bottled fish oil.
A practical method for ingestion of 10 mL to 15 mL per day of fish oil has been
Beyond symptomatic benefits of fish oil: considerations of cardiovascular benefits in rheumatoid arthritis
RA confers an approximate threefold increased risk of myocardial infarction and an approximate twofold increased risk of sudden cardiac death [38]. The increased cardiovascular risk is not explained by traditional risk factors and appears to be related to the extent of disease activity as measured by systemic inflammatory markers or extra-articular disease [39].
Cardiovascular risk may be further increased in RA patients because of the frequent use of NSAIDs for symptomatic relief. Using a
Summary and perspectives
Fish oil is not widely used in RA therapy, despite the following, all of which has been presented above:
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There is high level evidence (meta-analysis of randomized, controlled trials) for symptomatic benefits
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There is biologic plausibility for its clinical effects (inhibition of inflammatory mediator production, production of anti-inflammatory mediators)
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There is reduction in use of NSAIDs, which confer cardiovascular risk as well as the well-known risk of gastrointestinal adverse events
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There is a
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