The major part of setting a diet suitable for a heart patient concerns the sodium (salt) content. Old-fashioned sources may suggest severe sodium (salt) restriction for cats with heart disease and heart failure. Today, it is known that in earlier stages of heart disease and heart failure, this approach may actually be negative and harmful. The cat is not allowed to ingest excessive sodium (salt), but must continue to ingest an appropriate amount of protein, calories, vitamins, and other nutrients. Because of that nutritionists express the sodium (salt) content of a diet in terms of milligrams (mg) per unit of caloric energy (e.g. 100 kcal metabolizable energy). If the cat ingests an appropriate amount of energy, it also takes in an appropriate amount of salt. This ratio of sodium to caloric density works out roughly as follows:
Mild Sodium Restriction: 80-100 mg per 100 kcal
Moderate Sodium Restriction: 50-80 mg per 100 kcal
Significant / Marked Sodium Restriction: 40-50 mg per 100 kcal
Extreme Sodium Restriction: 20-40 mg per 100 kcal
Cats with no obvious signs of heart disease
If a cat has no obvious signs of heart disease, only mild sodium (salt) restriction is recommended. At this stage, it is more important to keep the sodium (salt) consumption at the same level every day to avoid sudden spikes in blood sodium level.
Cats with moderate heart disease (heart enlargement)
For cats with moderate heart disease moderate sodium restriction is recommended
Cats with severe heart disease / congestive heart failure
For cats with congestive heart failure significant sodium (salt) restriction is recommended and with refractory congestive heart failure may require extreme sodium restriction to help maintain their comfort when symptoms cannot be well-controlled with medication.
Cats with severe heart disease lose the ability to sufficiently eliminate sodium (salt) from the body. Severe heart disease causes a cascade of changes in kidney function and the central nervous system whereby sodium (salt) and water are retained. The increased distention of the veins eventually causes pressure to raise to a degree that forces fluid through the walls of the smallest blood vessels and into the surrounding tissues. This creates the condition known as "congestive heart failure" (CHF). Part of the treatment of CHF involves severe restriction of sodium (salt) consumption in the diet. It is extremely important that the owner of the cat with cardiac disease monitor this restriction.
Note: High sodium (salt) foods including commercial treats should always be avoided. Water can also contain high levels of sodium (salt). Contact your water supplier for information and consider bottled water as a substitute if necessary. An excellent option to commercial treats are lean meats.