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EPA and DHA
Omega-3 fatty acids
The most important representatives of the omega-3 fatty acid family are the plant-based alpha-linolenic acid (ALA) and the marine fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). All three fatty acids are essential for mammals. Theoretically, the long-chain fatty acids EPA and DHA can be synthesised from ALA, but the conversion rate is very low in dogs (< 5 %) and non-existent in cats due to a missing enzyme. As anti-inflammatory and other health-promoting effects are primarily attributable to EPA and DHA, it makes sense to supplement fish oil for some diseases. There are now products with EPA / DHA concentrates, so that sufficiently high quantities of these fatty acids can be administered with small doses.
Anti-inflammatory effect of EPA and DHA
It has been known for some time that the administration of EPA and DHA alters the profile of eicosanoids released during an inflammatory reaction. A number of new mechanisms by which
EPA / DHA influence the various aspects of the inflammatory response have only recently become the focus of research.
Areas of application of EPA and DHA
Cardiovascular diseases
It has been proven that dogs and cats with cardiac insufficiency benefit from EPA / DHA supplements. For example, food intake and thus cardiac cachexia can be improved and survival time extended.
survival time can be achieved. As heart failure is associated with inflammatory processes, it is assumed that the various anti-inflammatory mechanisms of omega-3 fatty acids form the essential biochemical basis for their positive effects. The various inflammation-regulating eicosanoids also have haemodynamic effects (Fig. 2). In humans, EPA / DHA supplementation has been shown to lower blood pressure. In cats suffering from cardiomyopathy, an antithrombotic effect is achieved through reduced platelet aggregation. Susceptibility to arrhythmias, especially atrial fibrillation, is also reduced.
Chronic kidney disease
The administration of EPA and DHA has proven effective as an accompanying therapeutic measure for chronic kidney disease in dogs and cats. Supplementing the diet with marine omega-3 fatty acids
omega-3 fatty acids slows the progression of chronic kidney disease by reducing glomerulosclerosis, lowering glomerular pressure and improving proteinuria, so that overall kidney function is maintained for longer.
Mechanism of action in detail
Influence on the profile of eicosanoids
The majority of pro-inflammatory eicosanoids are formed from the omega-6 fatty acid arachidonic acid (ARA). Supplementing the diet with long-chain omega-3 fatty acids inhibits the formation of arachidonic acid. In addition, they themselves are incorporated into cell membranes to a greater extent than arachidonic acid. If cells die during inflammation, more EPA and DHA are released, which compete with arachidonic acid for the enzymes lipoxygenase and cyclooxygenase, so that proportionally more mediators with a lower pro-inflammatory potential are formed (Fig. 1).
Resolvins and protectins
Only in recent years has it been recognised that counter-regulatory substances that actively contribute to the resolution of inflammation play a major role in the inflammatory process. Until then, the resolution of inflammation was thought to be a passive process; today we know that there are various potent lipid mediators that have independent anti-inflammatory and immunomodulatory properties and are actively involved in the resolution phase of inflammation. These so-called resolvins and protectins are formed enzymatically from EPA and DHA, with EPA serving as a precursor for E-series resolvins and DHA as a precursor for D-series resolvins and protectins (or neuroprotopectins) (Fig. 1). In this respect, DHA has a specific effect in the brain.
Influence on inflammatory genes
Many of the anti-inflammatory effects of long-chain omega-3 fatty acids also appear to be due to changes in gene expression. Various in vitro studies show, for example, an inhibition of the activation of the transcription factor NF-kappaB, which plays a central role in the development and maintenance of inflammation by upregulating the genes for inflammatory cytokines and COX-2, among others.
Among other things, DHA and EPA have an anti-inflammatory and anti-inflammatory effect. Other positive properties of EPA and DHA are their antithrombotic, antihypertensive, antiarrhythmic, antioxidant and neuroprotective effects,
antioxidant and neuroprotective effects.
Osteoarthritis
Numerous studies have shown the benefits of long-chain omega-3 fatty acids for rheumatoid arthritis in humans. The improvements achieved include a reduction in pain, stiffness and joint swelling as well as a reduction in the use of glucocorticoids and NSAIDs. In a systematic review of the literature on the efficacy of oral supplements in animals with osteoarthritis, the strongest evidence for an effect was found for omega-3 fatty acids. For example, in dogs with chronic osteoarthritis receiving carprofen for pain relief, the dose of carprofen was reduced by supplementation with omega-3 fatty acids from fish oil. Other studies have shown an improvement in clinical symptoms with EPA / DHA supplementation.
Inflammatory skin diseases
Inflammatory skin diseases are often characterised by severe itching, which is very stressful for the animals. Allergic skin diseases can be significantly improved by supplementing omega-3 fatty acids. The administration of EPA and DHA leads to a reduction in itching and inflammation as well as an improvement in alopecia and coat quality. Omega-3 fatty acids have a cortisone-sparing effect; in some animals (up to 20 %), administration alone is even sufficient as an alternative therapy.
Improvement of cognitive brain function
In the human sector, the neuroprotective benefits of EPA / DHA supplementation are often cited. There is a positive influence on cognitive functions, attention, short-term memory and learning and memory capacities.
Various epidemiological studies have shown that a diet rich in fish is associated with better brain function. While an undersupply of long-chain omega-3 fatty acids promotes neuroinflammatory processes and associated disorders, higher plasma EPA levels are associated with slower cognitive deterioration and a reduced risk of dementia and depressive symptoms in older people. In particular, EPA / DHA supplementation can improve so-called "mild cognitive impairment" (MCI) in old age.
No studies have yet been carried out on the effect of EPA / DHA supplements on declining cognitive function in older dogs and cats. However, their use appears to be justified, particularly in the presence of other age-related diseases that can be influenced by omega-3 fatty acids.
Take home
Possible areas of application for EPA / DHA preparations: Skin diseases, heart disease, chronic kidney disease, cognitive dysfunction, osteoarthritis
Proven effects: anti-inflammatory, antithrombotic, antihypertensive, antiarrhythmic, antioxidant and neuroprotective
- Cortisone savings for allergy sufferers and atopics
- Reduction in the administration of NSAIDs for osteoarthritis
Side effects only in case of overdose: increased bleeding tendency, increased sensitivity to oxidative stress, reduced serum vitamin E levels.
EPA and DHA reduce both inflammatory and cartilage-degrading processes in chondrocyte metabolism, in which the following mechanisms are involved:
- Production of fewer pro-inflammatory eicosanoids by displacing arachidonic acid in the chondrocytes
- Increased formation of inflammation-dissolving lipid mediators (resolvins, protectins)
- Reduction in the gene expression of inflammatory factors such as COX-2 and cytokines
- Reduction in the gene expression of cartilage-degrading enzymes (aggrecanases)
