Frequently Asked Questions about the Influence of Diet on Cardiovascular Diseases

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My cat suffers from compensated hypertrophic cardiomyopathy. Should its diet have a low sodium content?

The traditional recommendation for cats with cardiac disease is a diet that is very low in sodium. The current data, on the other hand, suggest that such a restriction will be beneficial only when the heart disease is decompensated. Too low a sodium content stimulates the reninangiotensin- aldosterone system (RAAS), which can have harmful effects on the cat’s heart and renal functions.

My cat suffers from decompensated hypertrophic cardiomyopathy (history of pulmonary edema). Should its diet have a low sodium content different than for compensated hypertrophic cardiomyopathy?

Sodium restriction (up to 0.5 g/1000 kcal) is justified when the cardiopathy has reached the stage of congestive heart failure.

Some results obtained in rats suggest that insufficient intake of energy by the cells may contribute to the development of hypertrophic cardiomyopathy. The administration of short- and medium-chain fatty acids is said to limit the consequences of cardiac hypertrophy. The benefit for cats has yet to be evaluated.

My cat suffers from systemic arterial hypertension. Should its diet have a low sodium content?

Large sodium intake (> 2 g/1000 kcal) must be avoided but clinical studies fail to determine whether a low-sodium diet facilitates medical treatment to control arterial pressure.

Major sodium restriction is not recommended in hypertensive cats. Excessive restriction will stimulate the renin-angiotensin-aldosterone system (RAAS), a classic pressure regulator, and promote hypokalemia by increasing potassium loss through the urine.

My cat suffers from systemic arterial hypertension secondary to chronic kidney disease. Is a food specifically formulated for cats with chronic kidney disease indicated or are additional nutritional measures needed?

Diets for cats with chronic kidney disease contain low or moderate levels of sodium (0.5 - 1 g/ 1000 kcal) (see chapter 7). In cats with chronic kidney disease showing a clear increase in arterial pressure, restricting the consumption of sodium chloride is not sufficient to prevent arterial hypertension, which must be treated medically.

Other nutrients that may help control arterial pressure include:

- Arginine: precursor of nitric oxide (NO), which helps regulate arterial pressure

- Omega-3 fatty acids, EPA and DHA: in humans, very high doses (>3 g/day) produce a vasodilator effect and a reduction in arterial pressure. This effect has not been established in cats.

My cat suffers from decompensated hypertrophic cardiomyopathy and chronic kidney disease. What type of food is best recommended?

Food with a sodium content of around 0.5 g/1000 kcal is recommended for cats with chronic kidney disease. Reducing the phosphorus content in this food will slow down the progression of the renal disease. Furthermore, foods formulated for cats with chronic kidney disease are enriched in omega-3 fatty acids, which is also beneficial in the event of cardiopathy.

My cat is obese and suffers from hypertrophic cardiomyopathy. What type of food should be prescribed?

The priority is implementing medical treatment and a diet that best supports cardiac function. Restricting energy intake will then be desirable, as obesity is associated with increased cardiovascular risk. Some studies on rodents show that dietary restriction reduces the level of oxidative stress and protects against some degenerative diseases, especially cardiomyopathies. This has not been studied in cats.

When should taurine deficiency be suspected during dilated cardiomyopathy?

Taurine deficiency in cats has been uncommon since the end of the 1980s, because commercial foods are now supplemented with taurine. This deficiency may however be suspected if the cat is fed a home-prepared ration, a vegetarian diet or poor quality foods. Measuring the taurine level in the whole blood (>250 nmol/mL) will help establish a definitive diagnosis. As central retinal degeneration is irreversible, it can be used to determine whether the cat has been fed with a taurine-deficient food for several months during the course of its life, but not whether its current diet is taurine-deficient.

Should cats with cardiac disease be prescribed potassium supplements?

Hypokalemia may appear with the use of diuretics (e.g., furosemide). Hypokalemia also occurs in 20% of cats with chronic kidney disease, and it increases the risk of hypertension (see chapter 7). Hypokalemia potentializes the toxicity of digoxin as well. In cardiopathic cats, the correction of hypokalemia through the supplementation of potassium is therefore strongly recommended.

Supplementation, on the other hand, is not necessary in the absence of hypokalemia. In cats treated with an angiotensin converting enzyme inhibitor, which stimulates reabsorption of potassium by the kidneys, the potassium content of the food must not be different from that of a maintenance food (1.5 - 2 g/1000 kcal).