Nutritional therapy in the treatment of heart disease in dogs - Heart Disease in Dogs

Alternative Medicine Review,  Sept, 2001  by Robert S. Dove

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Studies on Boxer dogs have shown the efficacy of oral supplementation with carnitine. (22-23) Families of dogs diagnosed with dilated cardiomyopathy were found to have decreased concentrations of myocardial L-carnitine when compared to control groups. When the diets of these dogs were supplemented with high doses of L-carnitine, their health and myocardial function improved greatly; removal of the supplemental L-carnitine caused a return of myocardial dysfunction and clinical signs of dilated cardiomyopathy. (23) Additional research shows that carnitine supplementation in dogs with taurine deficiency can allow conventional cardiovascular drug therapy to be discontinued in some cases. While myocardial function did not completely return to normal in all animals treated with carnitine therapy, it provided the dogs a normal quality of life for months to years. (4)

L-carnitine can improve heart rate, lipid patterns, and exercise tolerance, and protect against cardiac necrosis, all of which are important to returning an animal to normal cardiac function. It is valuable to understand L-carnitine in relation to taurine deficiency and supplementation, as the two nutrients have interrelated roles in management of heart disease in dogs. (24)

Taurine

Taurine, an amino acid found in relatively high concentration in heart tissue, is closely linked with cardiovascular health. It is thought that taurine works as a cardioprotectant by regulating natriuresis and diuresis, exhibiting positive inotropic effects on myocytes, and minimizing the adverse effects of angiotensin II. (25) Taurine has also been shown to decrease the level of lipid peroxides (and hence, oxidative damage) in hypoxic tissues, (26) and exert anti-arrhythmic effects in cardiac muscle. (27)

Taurine supplementation, at 100 mg/ kg/daily over the course of a month, reduced mortality rates, improved clinical condition, and enhanced myocardial contractility in dogs with congestive heart failure as compared to controls. (28) Other researchers have found taurine to slow the rapid progression of heart failure and prolong life expectancy in animals. (29)

In several breeds, taurine deficiency is thought to be one of the leading factors in the pathogenesis of canine (and feline) heart disease; specifically, dilated cardiomyopathy. This is noted especially for breeds such as the American cocker spaniel, Portuguese water dog, and Doberman pincher. (3,30) These relationships highlight taurine as potentially one of the most important nutrients under consideration for nutritional supplementation. It is an effective cardiotonic compound, especially where deficiency exists.

Omega-3 fatty acids

The omega-3 fatty acids, eicosapentanoic acid and docosahexanoic acid, are found almost exclusively in seafood, and especially fish oil from oily, cold water fish such as herring and mackerel. Fish oil possesses hypotriglyceridemic, anti-inflammatory, hypotensive, antiarrhythmic, antivasopressor, and anti-intimal thickening activities. (31-33) Because these compounds are not produced endogenously, they must be introduced by means of the diet or intravenous infusion. Oral supplementation has been found to be as effective as intravenous administration in producing antiarrhythmic actions in dogs with pre-existing heart disease, even though it is not as direct a route of action. When ingested, the fatty acids are initially stored in the membrane phospholipids of the heart, brain, and other tissues where they are not cardioprotective. However, in cases of ischemia, exertion, or major sympathetic adrenergic discharge, the stored fatty acids are quickly liberated by phospholipases and lipases, allowing them to act as in their free form to prevent arrhythmias. (32)