Metabolic Availability of Lysine From Barley in Young 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. Barley is an important cereal grain in the diet. The protein in barley is low in the essential amino acid lysine. Hence barley 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. It is important to assess the effect of different cooking methods on the lysine availability of barley.

Each subjects will receive each of up to 10 experimental diets for the Barley Study (4 reference protein diets providing, 3 Barley diets using dry cooking method, and 3 Barley diets using moist heat cooking method) in random order over a series of up to 10 experimental periods. The reference protein diet will be patterned after the AA pattern of egg protein using crystalline AA as the protein source. Three of the 4 lysine levels will be replaced by lysine provided in Barley each cooked using two different cooking methods ( dry and moist-heat).Each experiment will be conducted over 3 days. Adaptation days: During days 1 and 2 the subjects will be adapted to the level of lysine being studied, consuming the same diet as they will receive on day 3 (IAAO study day). The adaptation diet will be consumed as 4 equal meals.Meals will be divided into 4 equal parts to be spread evenly throughout the day and consumed in their usual environment on their usual activities of daily living. IAAO study day/isotope delivery and sample collection day: On the oxidation study day 3, following a 12-h overnight fast, subjects will come to the Hospital for Sick Children, Toronto, ON for a period of 5.5 h. On the oxidation study day, the diet is consumed as 9 iso-nitrogenous and iso-energetic hourly meals. Between meals, subjects are allowed to rest on bed, watch television or use a computer. Study days for each participant will be separated by ≥ 1 week. For the duration of all experiments, subjects will consume a daily multivitamin (Centrum Forte, Whitehall Robins) and 500 mg choline supplement (Nature's Way or equivalent), to ensure adequate vitamin intake. The multi vitamin supplement is provided to ensure that no vitamin cofactors are limiting in the diet which could alter metabolic pathways and functioning.