Quantitative Measurement of Nutritional Substrate Utilization in Patients With Amyotrophic Lateral Sclerosis (ALS)

The work of Nau et. al (Nau KL, Bromberg MB, Forshew DA, Katcha Vl. Individuals with amyotrophic lateral sclerosis are in caloric balance despite losses in mass. J Neurol Sci 1995;129 :47-49) showed that patients in the early stages of ALS initially increase their body fat. Another study showed that advanced ALS patients on mechanical ventilation were actually hypometabolic, supporting a hypothesis that ALS patients' daily oral intakes of calories fail to match their energy requirements, thus exacerbating their condition. This current study investigates and compares substrate utilization using a metabolic cart in controls and in ALS patients who are on and off ventilatory support to examine differences in substrate utilization between the two groups of ALS patients and the controls. (Substrate utilization is essentially the percentage of fats, carbohydrates, and protein utilized by the body.) The study will increase our understanding of the nutritional needs of ALS patients and improve our ability to provide the best possible nutrition in progressive illness.