Utilization of the Protein and Energy of the White Potato by Human Infants

Abstract

The digestibility and protein quality of the white potato were studied in 11 infants, ages 8–35 months, recovering from malnutrition. Seven 9-day dietary periods comprised the study. Digestibility was assessed by metabolic balance during the last 6 days of dietary periods in which potato provided 25%, 50% or 75% of dietary energy. Casein-based control dietary periods preceded and/or followed each potato dietary period. Fecal wet and dry weights, fecal energy, computed fecal carbohydrate and fecal fat during consumption of the 25% potato diet did not differ from control. Analysis of variance showed that consumption of increasing amounts of potatoes produced a significant linear increase in all parameters of digestibility except fecal fat. Fecal wet weight and energy content during the 75% potato period were more than double control values. Regression analysis of data from potato dietary periods showed fecal wet weight to be an excellent predictor of fecal dry weight (r = 0.904), energy content (r = 0.785) and computed fecal carbohydrate (r = 0.770). Protein quality of potato was assessed with N balance studies during the dietary periods in which potato provided all dietary protein (∼5% protein kcal). Apparent N retention was 78% of that from an isonitrogenous casein control diet. Decreased apparent N absorption was primarily responsible for the difference; the “biologic value” (percent of absorbed N that was retained) was similar for both diets.