Are the "ounce-equivalents" in the Protein Foods Groups Really Equivalent?

Over the past 35 years the United States Department of Agriculture (USDA) Dietary Guidelines for Americans (DGAs) has sought to translate recommendations on nutrient requirements (i.e., Recommended Dietary Allowances (RDAs) from the Food and Nutrition Board of the Institute of Medicine (IOM) into practical nutritional advice for the American public. Over the same time interval in which the Dietary Guidelines have existed the occurrence of nutrition-related health problems in the United States has escalated dramatically, showing that the population of obesity in U.S. has reached to a total of 35.8%. In addition, the lack of appropriate focus on protein nutrition is a major shortcoming of the DGAs. Not only is the amount of protein not a major focus, but also absolutely no mention is made of protein quality. Protein quality refers to the amount, profile, and true ileal digestibility of the essential amino acids (EAAs) in the protein. However, the concept of protein quality is not new, as the Protein Digestible Corrected Amino Acid Score was published by the Food and Agriculture Organization of the World Health Organization in 1993. Although animal protein (and beef specifically) has much higher the Digestible Indispensable Amino Acid Score (DIAAS) than plant proteins, often by as much as two fold, DIAAS has not taken account of the importance of the amount and profile of EAAs in individuals proteins. Moreover, the misrepresentation of the equivalencies of various food sources of protein in MyPlate raises the question of the process by which this occurred, and how can the process be influenced to more accurately reflect that high quality of animal proteins, including beef? Therefore, we propose to make these measurements in response to intake of "equivalent "(according to MyPlate) amounts of beef, kidney beans, eggs and peanut butter. Demonstration that the functional responses to these varied sources of protein coincide with the predictions from the USDA nutrient data base and calculation of the DIAAS will provide needed support to redefine "ounce equivalents" of protein food sources according to those data bases for all animal and plant sources of protein.

Inclusion criteria

• Men and women, ages 20-40 years
• BMI from 20 to 29.9 kg/m2

Exclusion criteria

• Current diagnosis of diabetes
• History of malignancy in the 6 months prior to enrollment
• History of gastrointestinal bypass surgery
• History of a chronic inflammatory condition or other chronic diseases (Lupus, HIV/AIDS, etc)
• Female subjects who are currently pregnant
• Subjects who are unable to eat animal protein
• Subjects who are unable to stop eating protein or Amino Acid (AA) supplements during the participation
• Subjects who report regular resistance training (more than twice per week)
• Subjects who have concomitant use of corticosteroids (ingestion, injection or transdermal)
• Hemoglobin less than 9.5 g/dL at the screening visit
• Platelets less than 250,000 at the screening visit.
• Any other disease or condition that would place the subject at increased risk of harm if they were to participate, at the discretion of the study physician