- What Are Fatty Acids?
- Overview of Fish Oils
- Uses of Fish Oil in Dogs and Cats
- Precautions and Side Effects
- How Fatty Acids are Supplied
- Fatty Acid Dosing Information for Pets
What Are Fatty Acids?
Fatty acids are an essential component to bodily function. Two fatty acids commonly discussed in veterinary medicine are omega-6 and omega-3. They are both required in dogs and cats and especially important, since animals are unable to produce these essential fatty acids independently. For this reason, fatty acids are supplemented in most high-quality commercial pet foods.
The benefits of fatty acids include anti-inflammatory properties that reduce flaky, itchy skin, improve allergies, and limit joint pain. Fatty acids can also support the immune system and potentially help fight cancer.
Key Points about Omega Fatty Acids for Dogs and Cats:
- The main types of omega-3 fatty acids include two long chain acids, frequently called free fatty acids, known as EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), and a short-chain omega-3 fatty acid known as ALA (alpha-linolenic acid). EPA and DHA are plentiful in fish (cold water), shellfish, flaxseed, and nut oils, while DHA is abundant in algae.
- Omega-6 fatty acids are found in meat products, grains (such as corn, soybean), vegetable oils (such as cottonseed, sunflower, black currant seed, evening primrose, and borage), egg yolks, and processed foods.
- Based on the normal diet, most dogs receive adequate amounts of omega-6 fatty acids, but are deficient in omega-3 fatty acids.
- Fish oil is often recommended as a good supplement for omega-3 fatty acids.
- It is important that pets not only get the appropriate amounts of fatty acids, but also get them in the proper ratio.
Below is information about the importance and function of fatty acids, therapeutic uses, side effects, drug interactions, and dosing.
Overview of Fish Oils
There are over 100 fatty acids. They are essential components of cell structure (particularly cell membranes) and are involved in a number of metabolic processes in dogs and cats.
The roles of fatty acids in the body include:
- Maintaining fluidity and flexibility of cell membranes
- Formation of short-lived hormone-like substances called prostaglandins, thromboxanes, and leukotrienes
- Maintaining health of the skin and its permeability to water
- Cholesterol esterification
- Energy production through oxidation in cells during exercise or starvation
Fatty acids attach to glycerol (via ester bonds) to form mono-, di- or triglycerides. Triglycerides are referred to as neutral fat, and store considerable energy for times of need. Phosphate-substituted triglycerides, called phospholipids, generally contain two rather than three fatty acids. Glycerol acts as a skeleton on which fatty acids are delivered to the body (in food), transported around the body (in plasma), and incorporated within cells and cell membranes. Free fatty acids are released within the intestine to facilitate their absorption.
Reconstituted triglycerides are transported in chylomicrons to be broken down into free fatty acids in blood vessel walls under the influence of insulin-activated lipoprotein lipase (LPL) to enable their transfer into cells. One fatty acid, linoleic acid, is considered essential in dogs and cats because it cannot be synthesized and must be supplied in the diet. All others, with the exception of arachidonic acid in cats, can be synthesized from linoleic acid, though the rate of conversion may not be adequate to meet bodily requirements in all instances. In this sense, they may be essential as well.
Fatty acids are required for the biosynthesis of eicosanoids (EA), including prostaglandins, thromboxanes, and leukotrienes. A delicate balance of EA helps control vascular tone, thrombin, and platelet activity. Omega-3 fatty acids give rise to Group 3 prostanoids and leukotrienes, the properties of which are generally considered helpful in terms of maintaining proper vascular integrity and blood flow. For this reason, omega-3 fatty acids have received a lot of attention as human dietary supplements to help prevent intravascular platelet aggregation and thrombus formation. Omega-6 fatty acids give rise to Group 2 prostanoids and leukotrienes. It can be argued that the ratio of omega-3 to omega-6 is as important to their biological action as their concentration in the supplement/diet.
In dogs and cats, the primary use of fatty acids is for their anti-inflammatory properties, including to palliate eczema-like skin eruptions and pruritus. Fatty acids have also been used to halt the progression of renal disease, retard tumorigenesis, reduce pain and inflammation, and prevent thrombus formation. It has also been shown to improve appetite in some cats with heart disease.
On face value, it would seem that dietary supplementation with fatty acids is something of a panacea, but a word of caution is indicated. Definitive studies confirming the efficacy and the safety of long-term supplementation have yet to be performed. Also, the optimal ratio of omega-3 to omega-6 fatty acids has yet to be established. A ratio of 5 to 10:1 omega-3 to omega-6 has been suggested as appropriate.
In addition, dietary supplementation with fatty acids is not without short and possibly long-term side effects. While fatty acid supplementation may ultimately be shown to have value, more studies are needed before such treatment can be unequivocally recommended.
Brand Names and Other Names of Fatty Acids/Omega Supplements
- Human formulations: Omega-3s: Promega Pearls Softgels® (Parke Davis), Cardi-Omega # Capsules® (Thompson Medical), EPA Capsules® (Nature’s Bounty), Sea-Omega 50 Softgels® (Rugby), Marine Lipid Concentrate Softgels® (Vitalline), Super EPA® 1200 Softgels and Super EPA® 2000 Capsules (Advanced Nutritional), and various generics.
- Dog fish oil formulations: 3 V Caps® and Derm Caps® (DVM), Linatone® (Lambert Kay), OFA® (Dermapet).
Please note, as over-the-counter products, fatty acid supplements do not need to be registered with the FDA.
Uses of Fish Oil in Dogs and Cats
Omega-3 and omega-6 fatty acids are used for treatment of a variety of conditions:
- Various dermatological problems:
- Pruritus (itchy skin) associated with atopy (allergies)
- Keratinization disorders, such as epidermal dysplasia, follicular dystrophy, ichthyosis, lichenoid psoriasiform dermatosis, primary idiopathic seborrhea, sebaceous adenitis, and Schnauzer comedo syndrome
- Immune-mediated skin disorder (Lupus erythematosus)
- Miliary dermatitis (cats)
- Eosinophilic granuloma (cats)
- Pain-related disorders:
- Pain associated with arthritis (hip dysplasia)
- Rheumatoid arthritis
- Various causes of joint pain
- Heart-related problems:
- Boxer dog arrhythmogenic right ventricular cardiomyopathy (ARVC)
- Heart failure (cats)
- Lymphoma and other tumors
- Cachexia associated with cancer
- Other Conditions:
- Intestinal inflammation (Inflammatory bowel disease)
- Renal disease
Precautions and Side Effects
Side effects of fish oil supplementation include:
- Increased free radical formation (with consequent lipid peroxidation) caused by increased intake of omega-3 fatty acids without adequate antioxidant protection.
- Hemorrhage, commonly presented as a nose bleed. It is important to monitor clotting parameters and avoid use when coagulopathies are present.
- Gastrointestinal upset such as vomiting and/or diarrhea, which can occur at high dosages. Learn more about home care for vomiting and diarrhea in dogs here.
- Lethargy (dogs only)
- Reduced release of insulin (monitor blood sugar). Fish oils should be used with caution in patients with non-insulin dependent diabetes (rare in dogs, common in cats). Learn more about diabetes here.
- Increased incidence of pancreatitis in predisposed breeds, such as Miniature Schnauzer, Miniature Poodles, and Cocker Spaniels. Learn more about pancreatitis here.
- Hypervitaminosis A, which is caused by products containing vitamin A. Symptoms may include lethargy, anorexia, weight loss, changes in sensitivity over the neck and forelimb region, stiffness or lameness in front legs, and constipation.
Drug Interactions with Fish Oil
Because of the effects of fatty acids on bleeding/coagulation times, it is probably unwise to administer fatty acid dietary supplements concurrently with anticoagulants, such as aspirin, warfarin, and heparin. Check with your veterinarian if your pet is on anticoagulants before using any nutritional supplement.
- Commercially available veterinary products contain a combination of fish oil (eicosapentaenoic and docosahexaenoic acids) and vegetable oil (gamma linoleic acid). They may also contain vitamin E (tocopherol), vitamin A, and vitamin D. Dosing forms are either capsules, tablets, chewable tablets, liquids, or granules.
- Human formulations of omega-3 fatty acids contain 600, 1000, or 1200mg of fatty acid per capsule, equivalent to N-3 fat content of between 168 – 563mg EPA and 72 – 312mg of DHA. Most have vitamin E added.
Fatty Acid Dosing Information for Pets
- As each product is different, the dosing regimen of fish oil in dogs suggested by the individual manufacturer should be followed.
- It may take 10 to 14 weeks or longer to see full therapeutic effects.
- Most veterinary formularies recommend to dose omega-3 fatty acids based on the metabolic weight and not the actual body weight. (Note: Metabolic weight takes into consideration a dog’s body weight, metabolism, energy level, and life stage). Dogs come in a variety of weights and sizes. A 25-pound dog does not need 5 times more than a 5-pound dog. The metabolic weight looks at the needs of energy-using tissues such as muscles and organs. There are scientific calculations, but you can roughly obtain a metabolic weight by taking your dog’s weight in pounds and dividing by 2.2 to get their weight in kilograms (kg) then multiplying this number by 0.75. For example, if your dog weighs 75 pounds and you divide by 2.2, their weight in kilograms is 34. If you multiply their weight of 34 kg by 0.75 – you get 25.6 as the metabolic weight. Your veterinarian can help you with this calculation.
- The dosage recommendation varies based on the condition being treated and the amount of fatty acids in the food.
- In dogs, published dosage recommendations include a daily allowance of 30 mg/kg0.75, 140 mg/kg0.75 for kidney disease, 310 mg/kg0.75 for osteoarthritis, 125 mg/kg0.75 for inflammatory or immunologic disorders – all based on metabolic weights.
- May be given with or without food.
- Products should be stored out of sunlight and heat.
- Most commercially available veterinary products contain a combination of vegetable oil (gamma linoleic acid), fish oil (eicosapentaenoic and docosahexaenoic acids), vitamin E, and Vitamin A.