Your body depends on leucine, and the seven other essential amino acids, for proper protein utilization and maintenance. According to the book "Anatomy and Physiology" by Kenneth Saladin, protein constitutes 12 to 15 percent of your body mass, with 65 percent located in muscle tissue. Therefore, leucine is an important amino acid for muscle health. Leucine can be found in egg whites.
Amino Acid Function
Protein is comprised of eight essential amino acids and 12 nonessential amino acids. Although all 20 amino acids must be present for protein synthesis, only essential amino acids have to be obtained from dietary sources, because nonessential amino acids are created in your body. Amino acids build, repair and regulate protein tissue internally. Leucine is an essential amino acid found in eggs, dairy and other animal products, and soybeans and lentils.
Leucine Function
Leucine plays an important role inside muscle tissue during physical activity. According to the book "Nutrition for Health, Fitness and Sport" by Melvin H. Williams, leucine undergoes changes within the muscle during exercise that ultimately lead to more energy. In addition leucine supports muscle growth during a resistance-training program. You can benefit from leucine by ingesting egg whites.
Leucine in Egg Whites
The white of one large egg contains 0.335 g of leucine while the yolk contains 0.238 g. Therefore, one large egg contains over ½ g of leucine. The whites of one large egg contain 17 calories, 3.6 g of total protein, 0.6 g of fat, 2 mg of calcium and 54 mg of potassium.
Additional Amino Acids
Egg whites contain all eight essential amino acids. One large egg white contains 0.096 g of histidine, 0.218 g of isoleucine, 0.266 of lysine, 0.132 g of methionine, 0.226 g of phenylalanine, 0.148 g of threonine and 0.041 g of tryptophan. Eggs are considered the gold-standard of protein due to their superior amino acid ratio. You can increase your amino acid intake by consuming egg yolks along with whites.
Protein Requirements
According to the United States Department of Agriculture, the typical adult requires 0.8 g of daily protein per kg of body weight or 0.37 g of daily protein per lb of body weight. A typical 70 kg adult requires 2,940 mg of leucine per day or 42 mg per kg of body weight each day. Eating egg whites is a great way to ensure adequate protein in your diet.
References
- "Nutrition for Health, Fitness and Sport"; Melvin H. Williams; 2007
- "Anatomy and Physiology"; Kenneth Saladin; 2004
- United States Department of Agriculture: Dietary Guidelines, Part D, Protein, PDF
- Incredible Egg: Nutrient Table
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