Metabolic Availability of Lysine From Sorghum in Adult Men

Overview

Protein is the key determinant of growth and bodily functions. The quality of food proteins depend on their amino acid content and the amount of amino acids used by the body to make proteins. Globally Cereal Grains (CG) provide 50% of the calories and protein in the diet and exceed 80% in poorer developing countries. In many of those countries, sorghum is the major cereal grain in the diet. The protein in sorghum is low in the essential amino acid lysine. Hence sorghum protein is of low quality. Low lysine affects protein synthesis in the body. Cooking methods also affect the lysine available from foods to the body.The protein can be complemented by the addition of lentils to augment the low lysine content. However, lentils are prohibitively expensive in some developing countries. As the human population increases, the world faces the continuous challenge of maximizing a limited food supply. Protein quality (PQ) evaluation of sorghum directly in humans would allow us to bridge the gap in knowledge between what is required and how best to provide.The information gathered from this project will provide the first direct experimental data on PQ of sorghum protein in humans on which nutrition recommendations can be built.

Each subject will be part of 8 different experimental diets, and randomly assigned to one of the diets every time. 4 reference diet would be based on egg protein composition, 3 sorghum diets would have protein from cooked sorghum and 1 mixed meal would comprise of cooked sorghum and lentils. Each experimental diet will be studied over 3 days: 2 adaptation and 1 study day. The 2 adaptation meals would be consumed at home. On the study day 3, following a 12-h overnight fast, subjects will come to the research unit at The Hospital for Sick Children, Toronto, ON for a period of 7.5 h and consume the diet as 9 hourly meals. The first 3 meals would be consumed at home. For the duration of all experiments, subjects will consume a daily multivitamin supplement to ensure adequate vitamin intake. Measurements: Resting energy expenditure (REE) will be measured by open-circuit indirect calorimetry Body composition (fat and fat free mass) will be measured by BIA and Skin Fold. Breath samples will be collected after the 4th and 7th meals.