Heart-Healthy Diet for Dogs and Cats: Nutrition for Cardiovascular Wellness

Nutrition plays a profoundly important role in cardiovascular health — both as a foundation for maintaining a healthy heart throughout life and as a modifiable factor that can either support or undermine cardiac function in pets with diagnosed heart disease. The relationship between diet and heart health in companion animals has received intense scientific attention in recent years, particularly following the investigation into a potential link between certain grain-free diets and dilated cardiomyopathy (DCM) in dogs, which brought the topic of cardiac nutrition into mainstream awareness among pet owners and veterinary professionals alike.

"What we feed our pets has direct, measurable effects on their cardiovascular system. Essential amino acids like taurine and L-carnitine are literally required for the heart muscle to function — deficiency leads to heart failure. Omega-3 fatty acids modulate inflammation and arrhythmias. Sodium intake affects fluid balance and blood pressure. And overall caloric balance determines body condition, which directly impacts cardiac workload. Nutrition is not a peripheral consideration in cardiac care — it is a central pillar." — Dr. Sarah Chen, DVM

The heart is one of the most metabolically demanding organs in the body, beating continuously from before birth until death — approximately 100,000 to 200,000 times per day in a dog, and even more in a cat. This relentless contractile activity requires a constant supply of energy (primarily derived from fatty acid oxidation in cardiomyocytes), specific amino acids and cofactors for muscle contraction and electrical conduction, and antioxidants to manage the oxidative stress generated by the heart's high metabolic rate. When any of these nutritional requirements is not met — whether due to an inherently deficient diet, malabsorption, increased metabolic demand from disease, or interference by dietary factors that reduce nutrient availability — the heart's function can be directly impaired.

Understanding cardiac nutrition requires recognising that dietary needs differ between healthy pets (where the goal is prevention and maintenance of cardiovascular wellness) and pets with diagnosed heart disease (where specific dietary modifications become part of the therapeutic plan). This guide covers both scenarios, providing evidence-based guidance to help pet owners make informed nutritional decisions that support their companion's cardiovascular health at every life stage. For a foundation in understanding pet food quality, see our guide on reading pet food labels.

Several specific nutrients have been identified as critical for maintaining normal cardiac structure and function in dogs and cats. Deficiency in any of these can directly contribute to the development of heart disease, while adequate or supplemental intake can support cardiac function and may slow the progression of existing disease.

Taurine is a sulphur-containing amino acid that is essential for normal myocardial (heart muscle) function, and its role in cardiac health has been extensively studied in both dogs and cats. Cats are obligate taurine-dependent — they cannot synthesise sufficient taurine from precursor amino acids and must obtain it directly from their diet. Taurine deficiency in cats was identified in the late 1980s as the primary cause of feline dilated cardiomyopathy, and the subsequent supplementation of commercial cat foods with adequate taurine levels virtually eliminated nutritional DCM in cats — one of the most dramatic success stories in veterinary nutrition. Dogs can synthesise taurine from methionine and cysteine, but certain breeds (Cocker Spaniels, Golden Retrievers, Newfoundlands, and others) appear to have reduced synthetic capacity or increased metabolic requirements, making them vulnerable to taurine deficiency under certain dietary conditions. Low plasma and whole-blood taurine levels have been documented in some dogs with dilated cardiomyopathy, and taurine supplementation in deficient dogs has been associated with significant improvement in cardiac function in some cases.

L-carnitine is an amino acid derivative that plays an essential role in fatty acid transport into the mitochondria, where fatty acids are oxidised to produce the ATP (energy) that fuels cardiac contraction. The heart derives approximately 60 to 70 per cent of its energy from fatty acid oxidation, making adequate L-carnitine availability critical for normal myocardial metabolism. L-carnitine deficiency has been documented as a cause of DCM in some dog breeds, particularly Boxers and Cocker Spaniels, and L-carnitine supplementation has been shown to improve cardiac function in deficient dogs. However, L-carnitine deficiency is difficult to diagnose definitively because plasma levels do not accurately reflect myocardial tissue levels — endomyocardial biopsy is the gold standard for diagnosis but is rarely performed due to its invasive nature. Because of this diagnostic challenge, empirical L-carnitine supplementation (typically 50 to 100 mg/kg/day divided into two to three doses) is often recommended for dogs with DCM, particularly those of predisposed breeds.

Omega-3 fatty acids — specifically EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) derived from marine sources (fish oil) — have multiple cardiovascular benefits that are supported by both human and veterinary research. Omega-3 fatty acids have anti-inflammatory properties that can reduce the chronic myocardial inflammation associated with heart disease, anti-arrhythmic effects that may reduce the frequency and severity of ventricular arrhythmias, anti-cachectic effects that help preserve lean muscle mass in pets with cardiac cachexia (the wasting syndrome that accompanies advanced heart failure), and potential anti-thrombotic effects that may reduce the risk of blood clot formation. Veterinary cardiologists commonly recommend omega-3 supplementation (typically 40 to 100 mg/kg/day of combined EPA and DHA) for dogs and cats with heart disease, sourced from high-quality fish oil supplements rather than plant-based omega-3 sources (flaxseed, which contains ALA but not the cardioprotective EPA and DHA).

Beginning in 2018, the US Food and Drug Administration (FDA) began investigating reports of dilated cardiomyopathy in dog breeds not traditionally predisposed to the condition, with many affected dogs having been fed diets marketed as 'grain-free' — diets that substituted traditional grains (corn, wheat, rice, barley) with legumes (peas, lentils, chickpeas), potatoes, or other alternative carbohydrate sources as primary ingredients. This investigation sparked intense debate within the veterinary and pet food communities and raised important questions about the relationship between diet composition and cardiac health.

The FDA's investigation identified over 1,100 reports of suspected diet-associated DCM by the time of their most recent update, with Golden Retrievers being the most commonly reported breed, followed by mixed breeds, Labrador Retrievers, Great Danes, and others. Many — though not all — of these cases involved dogs fed diets where legumes, legume-derived proteins, or potatoes appeared as primary ingredients (often among the first five to ten listed ingredients). Some affected dogs had low taurine levels, and a proportion showed improvement in cardiac function when switched to grain-inclusive diets and supplemented with taurine. However, others had normal taurine levels, and the improvement in cardiac function after diet change was not universal, complicating the mechanistic explanation.

Despite extensive investigation, a definitive causal mechanism linking specific grain-free diet ingredients to DCM has not been conclusively established. Several hypotheses have been proposed: that high legume content may interfere with taurine synthesis, absorption, or recycling; that legume-based proteins may be less bioavailable than animal-based proteins for taurine precursor amino acids; that certain fibres in legumes may increase faecal taurine losses; or that the relationship is more complex, potentially involving multiple interacting nutritional factors, genetic predisposition, and individual metabolic variation. For a deeper comparison of diet types, see our guide on raw vs commercial pet food.

The practical take-home for pet owners, based on current evidence and the consensus guidance from veterinary nutrition and cardiology specialists, is as follows: feed a diet from a manufacturer that employs board-certified veterinary nutritionists, conducts feeding trials (not just laboratory nutrient analysis), and has a robust quality control programme; if you choose to feed a grain-free diet, do so for a specific, documented reason (such as a confirmed grain allergy diagnosed through an elimination diet trial) rather than based on marketing claims; monitor your dog for any signs of cardiac disease (cough, exercise intolerance, breathing difficulty, lethargy); and discuss diet selection with your veterinarian, particularly if your dog belongs to a breed with known DCM predisposition. The investigation is ongoing, and recommendations may evolve as more data become available.

When a pet has been diagnosed with heart disease, nutritional management becomes a specific, tailored component of the overall treatment plan. The dietary goals shift from general health maintenance to targeted interventions that support cardiac function, manage symptoms, slow disease progression, and maintain body condition — which is particularly challenging in pets with advanced heart disease who may be struggling with both appetite loss and cardiac cachexia.

Sodium restriction is perhaps the most widely discussed dietary modification for pets with heart disease, though its implementation requires nuance. In pets with congestive heart failure (CHF), excessive sodium intake can exacerbate fluid retention by increasing blood volume and promoting oedema and effusion. Current guidelines recommend mild sodium restriction for pets in early stages of heart disease (avoiding high-sodium treats and table food) and more significant restriction for pets with active CHF — typically limiting dietary sodium to less than 80 mg per 100 kcal for dogs and less than 100 mg per 100 kcal for cats in moderate-to-severe CHF. However, overly aggressive sodium restriction should be avoided, particularly in asymptomatic pets, as it can activate the renin-angiotensin-aldosterone system (RAAS) — the very neurohormonal pathway that contributes to heart failure progression — and may reduce appetite and palatability at a time when maintaining caloric intake is critical.

Caloric adequacy and maintaining body condition is a crucial and often underappreciated aspect of cardiac nutrition. Pets with moderate-to-severe heart disease are at high risk of cardiac cachexia — a complex metabolic syndrome characterised by progressive loss of lean muscle mass driven by chronic inflammation, neurohormonal activation, and altered metabolism. Unlike simple starvation (which primarily depletes fat stores), cachexia preferentially destroys skeletal muscle, reducing the pet's strength, mobility, and overall vitality. Maintaining adequate caloric intake — ideally with a diet that provides high-quality, highly digestible protein to support muscle maintenance — is essential for combating cachexia. Appetite stimulants (mirtazapine in cats, capromorelin in dogs) may be prescribed when reduced appetite threatens nutritional status.

Therapeutic cardiac diets are commercially available veterinary prescription diets specifically formulated for pets with heart disease. These diets are typically moderately sodium-restricted, enriched with taurine, L-carnitine, and omega-3 fatty acids, and formulated for high palatability and digestibility. Examples include Royal Canin Cardiac, Hill's h/d, and Purina Pro Plan Veterinary Diets CC CardioCareBT. While these diets can be valuable tools, they may not be appropriate for every cardiac patient — for example, a dog with concurrent kidney disease and heart disease has competing dietary requirements that may necessitate a customised feeding plan developed in consultation with a board-certified veterinary nutritionist. Always discuss specific dietary changes with your veterinarian, especially if your pet is on weight management or has multiple health conditions requiring dietary consideration.

Beyond the essential nutrients discussed earlier (taurine, L-carnitine, omega-3 fatty acids), several additional supplements have been studied for their potential cardiovascular benefits in dogs and cats. While the evidence base for veterinary cardiac supplements is less extensive than for human cardiology, some supplements have sufficient support to warrant consideration as part of a comprehensive cardiac care plan.

Coenzyme Q10 (CoQ10 or ubiquinone) is a fat-soluble compound that plays a critical role in mitochondrial energy production and also functions as a potent antioxidant. The heart, with its exceptionally high metabolic rate, contains the highest concentration of CoQ10 of any organ. Studies in both human and veterinary patients with heart failure have demonstrated reduced myocardial CoQ10 levels, and supplementation has been associated with improved cardiac function parameters in some human trials. In dogs, CoQ10 supplementation has been studied primarily in the context of DCM, with some studies suggesting modest improvements in echocardiographic indices of cardiac function. The typical supplemental dose in dogs is 1 to 3 mg/kg/day, and the ubiquinol form is considered more bioavailable than the ubiquinone form. While CoQ10 is generally safe and well-tolerated, it should be considered a complement to — not a replacement for — standard cardiac medications.

Magnesium is an essential mineral involved in hundreds of enzymatic reactions, including those governing cardiac electrical conduction and muscle contraction. Magnesium deficiency can contribute to cardiac arrhythmias, and dogs with heart failure may have reduced magnesium levels due to diuretic therapy (furosemide increases urinary magnesium loss) and reduced dietary intake. Magnesium supplementation may be beneficial for dogs with documented hypomagnesaemia or those on chronic high-dose diuretic therapy, though routine supplementation without documented deficiency is not universally recommended. The relationship between magnesium and cardiac rhythm is particularly relevant for dogs receiving digoxin, as hypomagnesaemia increases the risk of digoxin toxicity.

Vitamin E and selenium serve as antioxidants that help protect cardiomyocytes from oxidative damage — a process that is accelerated in failing hearts due to increased reactive oxygen species production. While deficiency of either nutrient can cause myocardial damage (selenium-deficient cardiomyopathy is well documented in livestock and has been reported in dogs), the benefit of supplementation above adequate dietary levels in pets with heart disease is less clearly established. Most high-quality commercial pet foods provide adequate vitamin E and selenium for healthy animals, but pets with malabsorptive conditions or those fed unconventional diets may benefit from supplementation. For comprehensive guidance on supplements for ageing pets, consult our resources on senior dog supplements and senior cat supplements.

A critical caveat for all cardiac supplements: they should never replace prescribed cardiac medications (pimobendan, diuretics, ACE inhibitors, antiarrhythmics), and pet owners should always discuss supplement use with their veterinarian before initiating any regimen, as some supplements can interact with medications or be contraindicated in certain conditions. The supplement market is also poorly regulated, and product quality varies significantly — veterinarian-recommended brands and products with independent quality verification (such as USP or NSF certification for human products, or veterinary-specific product lines) are preferred over unverified products.

Translating nutritional science into everyday feeding practices is where theory meets reality for pet owners. Whether you are feeding a healthy pet with the goal of preventing cardiovascular problems, or managing the diet of a pet with diagnosed heart disease, the following practical strategies provide an evidence-based framework for supporting your pet's cardiac health through nutrition.

For healthy pets — preventive nutrition: Feed a complete and balanced diet from a reputable manufacturer that meets AAFCO (in the US) or FEDIAF (in Europe) nutritional standards for your pet's life stage. Ensure the diet provides adequate levels of taurine (particularly important for cats and at-risk dog breeds), is based primarily on high-quality animal protein sources (which naturally provide taurine, L-carnitine, and essential amino acids), and includes marine-sourced omega-3 fatty acids. Maintain your pet at a healthy body condition score (4 to 5 out of 9) — obesity places significant additional workload on the heart and is an independent risk factor for cardiovascular disease. Avoid excessive sodium from treats and table scraps (many human foods, including processed meats, cheese, bread, and canned vegetables, contain far more sodium than is appropriate for pets). If you feed treats, ensure they constitute no more than 10 per cent of daily caloric intake and choose low-sodium options.

For pets with diagnosed heart disease: Work closely with your veterinarian — and ideally a board-certified veterinary nutritionist for complex cases — to develop a dietary plan tailored to your pet's specific cardiac condition, stage of disease, concurrent health issues, and individual preferences. Transition to any new diet gradually (over seven to ten days) to avoid gastrointestinal upset and ensure acceptance, which is particularly important for pets whose appetite may already be compromised. Feed multiple small meals throughout the day rather than one or two large meals — this reduces the metabolic demand on the heart associated with digesting and processing large meals, and may improve appetite in pets that are reluctant to eat large quantities. Monitor body weight and body condition score weekly, as unintentional weight loss can occur insidiously and may indicate worsening cachexia or inadequate caloric intake. Report any changes in appetite, body condition, or dietary tolerance to your veterinarian promptly.

Treats and food toppers for cardiac patients: Many commercial treats are surprisingly high in sodium, which can undermine the sodium-restricted diet prescribed for pets with CHF. Read labels carefully — or better yet, use small pieces of low-sodium, single-ingredient treats such as plain cooked chicken breast, unsalted green beans, blueberries, or small amounts of banana. Pill pockets and flavoured medication wrappers should also be checked for sodium content. For pets with reduced appetite, warming food slightly (to just below body temperature) enhances aroma and palatability, and adding a small amount of low-sodium broth or water to kibble can increase moisture content and appeal. Understanding pet food labels empowers owners to make heart-conscious choices for treats and diets alike.

The overarching message is that cardiovascular nutrition is not a one-size-fits-all proposition. A healthy puppy, a middle-aged Cavalier King Charles Spaniel with early mitral valve disease, and a senior Doberman Pinscher with advanced DCM and CHF all have different nutritional needs. Working with your veterinary team to identify and implement the right dietary strategy for your individual pet is one of the most impactful things you can do to support their cardiovascular health and quality of life.