High Salt Diets Bad for Heart Failure Patients

Each year another 670,000 Americans are diagnosed with heart failure (HF) and there are now close to 6 million Americans living with failing hearts. About 20% die within a year of diagnosis and less than half survive 5 years after being diagnosed with HF.

Nearly 300,000 people die from HF each year. Only heart attacks and cancer kill more Americans. Deaths from coronary artery disease have been falling for the past 40 years but deaths attributed to HF have more than doubled. About 14% of those 65y and older have HF but they account for about 42% of all Medicare hospitalization expenditures. Many factors like increasing age, smoking, heart attacks, heart valve problems, cardiac arrhythmias, heavy alcohol intake, obesity, and diabetes damage and weaken the heart over time and contribute to the development of HF. However, the biggest risk factors for the development of HF is hypertension and left ventricular hypertrophy (LVH). There is growing evidence hypertension is largely caused by excessive salt intake, which is known to stiffen arteries in the short term and eventually thicken the arteries and leads to LVH. In response to excess salt, elevated blood pressure, and other insults the heart gradually thickens and stiffens due to the build-up of scar-like connective tissue. LVH may simply be the beginning of HF. However, hypertension and LVH can usually be reversed by a healthy low-salt diet, whereas once HF develops there is no cure. The failing heart becomes grossly enlarged and gradually losses it ability to pump blood efficiently. In some patients the stiffened heart does not allow left ventricle to fill properly leading to diastolic HF. In others, with systolic HF the ability of the heart?s left ventricle to contract eject most of its contents into the aorta is markedly reduced. The heart?s reduced ability to pump blood to the kidneys in HF reduces the body?s ability to get rid of excess salt and fluid. As salt and fluid increase in the body edema develops in the legs, abdomen, and elsewhere. There can also be a build-up of fluid in the lungs leading to a reduced ability to oxygenate the blood and congestion. Most people admitted to the hospital with congestive HF cannot get enough blood and oxygen to their tissues or get rid of the excess salt and fluid. They are in a downward spiral is called acute decompensated heart failure (ADHF) that can lead rather quickly to death. Medical treatment consists of potent IV diuretics to get rid of the excess salt and fluid and often drugs to improve heart function. Salt and fluid intake are generally restricted until these patients are stabilized. Once stabilized HF patients are typically sent home with little or no dietary advice. Current medical guidelines for managing stable HF patients emphasizes drug treatment and allows a sodium intake of up to 4000mg per day or about the average intake for most adult men. For those with hypertension sodium is restricted to <2300mg/day. Even though most HF patients had hypertension - often for many years their weakened hearts frequently cause BP to drop back into the ?normal? range. This lack of concern about salt intake in stable HF patients seems odd given the prominent role that excessive salt intake plays in causing hypertension and LVH.1 Part of the reason for this lack of concern about salt intake in HF patients is little data showing a benefit from a reduced salt intake. Sadly there has been little research as to what could be done to prevent repeated ADHF episodes.That is now changing. A prospective study followed a group of 123 systolic HF patients whose condition was stable for at least 3 months at home. Their sodium intake was carefully measured with 3-day diet logs and confirmed with 24 hour urinary sodium measurements. Patients were divided into 3 groups based on their average sodium intake. The 41 subjects with the lowest salt intake averaged 1400mg of sodium while the middle third middle and top third of subjects averaged 2400 and 3800mg/ day, respectively. After 3 years of follow-up hospitalization for ADHF occurred in 12%, 15%, and 46% of patients in the low, moderate, and high-sodium groups, respectively. The authors concluded, ?These data provide support for more stringent sodium intake guidelines than those currently recommended for HF patients.?2Bottom Line:?Given the soaring costs of repeatedly hospitalizing HF patients perhaps it is time for medical guidelines to limit salt intake in stable ambulatory heart failure patients. Heart failure patients may also benefit from supplements of Vitamin D and CoQ-10, as well as, an increased intake of omega-3 fatty acids. More on this next month.By James J. Kenney, PhD, RD,?FACNReferences:1. Am J Clin Nutr. 2011;93:229-312. Am J Clin Nutr 2011;93:332-7