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Abstract & Commentary
Synopsis: Non-obese, free-living patients with clinically stable CHF have an inadequate intake of calories and protein and reduced energy availability for physical activity.
Source: Aquilani R, et al. J Am Coll Cardiol. 2003;42: 1218-1223.
It has been estimated that as many as 50% of hospitalized congestive heart failure (CHF) patients are malnourished.1 Aside from the dietary restrictions related to edema, coronary artery heart disease, and/or hyperlipidemia, minimal attention has been given to general dietary assessment, evaluation, and instructions. An inadequate calorie and protein intake in clinically stable CHF patients is an added catabolic insult that contributes to muscle protein breakdown and progressive deterioration of important cellular substrate concentrations of muscle glycogen and amino acids.2
Aquilani and colleagues investigated the total energy expenditure, calorie intake, nitrogen intake, total nitrogen excretion, energy availability, and nutritional adequacy in 57 non-obese CHF patients. Nitrogen balance was found to be significantly diminished, and energy availability was 41% lower in CHF patients when compared to a control group. They concluded that CHF patients have an inadequate intake of calories and protein and, in addition, have significantly reduced energy availability for physical activities.
Comment by Harold L. Karpman, MD, FACC, FACP
Aquilani et al have demonstrated that a useful method to assess nutritional adequacy in clinical practice is to calculate the calorie-nitrogen balance (CNB) that reflects the daily homeostasis between calorie-nitrogen intake over nitrogen excretion and its relationship to total energy expenditure. Despite similar calorie and nitrogen intake, a significant number of CHF patients demonstrated a negative calorie balance (70.1%), negative nitrogen balance (59.6%), or a negative combined CNB (40.3%) when compared to a control group. Since total energy expenditure was the same in the CHF patients and in the control population, it becomes obvious that CHF patients often simply do not have enough energy available for the extra energy expenditure required by ordinary activities of living, during periods of decompensation, when infection is present, or when exercising.
From a therapeutic point of view, the depleted CHF patients should have a daily intake of at least 31.8 Kcal/kg and 1.37 g protein/kg, whereas normally nourished CHF subjects should have at least 28.1 Kcal/kg and 1.12 g protein/kg in order to preserve their actual body composition or limit the effects of hypercatabolism. Great caution should be observed in prescribing a low-calorie diet for overweight CHF patients because of the risk of causing and/or increasing body protein breakdown that may result in weight loss; however, the weight loss in these patients may be due to the loss of muscle mass rather than fat with a resulting increase in generalized weakness.
Aquilani et al’s prospective analysis of the nutritional balance in patients with CHF should alert us to the possibility that many of our CHF patients are biologically starving before our very eyes and therefore, besides the usual salt and/or fluid restrictions which physicians often prescribe for CHF patients, we will have to pay increased attention to calories and protein in order to be certain that CHF patients have adequate nutrition for their body needs.
1. Freeman LM, et al. Nutr Rev. 1994;52:340-347.
2. Opasich C, et al. Eur Heart J. 1996;17:1686-1693.