3.1. Study Diet
Estimated choline, choline forms, L-carnitine, and methionine content of the study diet separated by beef group are shown in Given that the 2022 USDA database does not include choline forms, glycerophosphocholine (GPC), phosphocholine, PC, and sphingomyelin were calculated using the 2008 USDA Database for the Choline Content of Common Foods [L-carnitine is not included in the USDA database, thus the National Institutes of Health Office of Dietary Supplements Carnitine Fact Sheet for Health Professionals was used to calculate dietary L-carnitine in the beef provided by the study diet [Nutritionist Pro™ software was used to estimate dietary methionine content of the diet. Each food item from the study was put into the software and Nutritionist Pro™ calculated the amount of methionine consumed. Participants in the 3 oz group received 1350 mg of methionine and the 6 oz group received 1957 mg of methionine.