Researchers reviewing 25 studies on protein suggest that the protein in eggs makes a valuable contribution to muscle strength, helps to satisfy hunger and provides a source of sustained energy. They suggest that because research shows eggs are rich in leucine, an essential amino acid that plays an important role in how muscles use glucose, they would be a valuable food for men and women undergoing endurance training.
The study, by Drs Donald K Layman and Nancy R Rodriguez, is published in the Jan/Feb 2009 issue of the journal Nutrition Today.
Layman is a professor emeritus at the Department of Food Science and Human Nutrition at the University of Illinois and researches amino acids and muscle metabolism, and Rodriguez is an associate professor of Nutritional Sciences, University of Connecticut Sports Nutrition Programs at the University of Connecticut and researches links between exercise and protein.
The study, which reviewed more than 25 published research papers on protein concluded that the protein in eggs contributes to strength, power and energy as follows:
- As it does not cause surges in blood sugar and insulin, the protein in eggs is a steady and sustained source of energy.
- Eggs are rich in protein and nutrients including thiamin, riboflavin, folate, B12 and B6, the B vitamins that are essential for energy production.
- One eggs supplies more than 6 grams of high quality protein (about 13 per cent of the daily value) which helps to preserve muscle mass and prevent muscle loss in older adults.
- Eggs are rich in leucine, an essential amino acid that helps the body use energy and muscles recover after exercise.
- Eggs have all the amino acids the body needs to build and maintain muscle mass.
- Eggs are often used as the “gold standard”, a comparison for assessing the protein content of other foods.
The authors wrote that:
“Given the unique complementary relationship between the EAA [essential amino acid] leucine and glucose utilization by muscle, it would follow that a diet rich in the amino acid leucine would be advantageous to men and women undergoing endurance training.”
Layman told the press that:
“While many Americans may be getting enough protein, they need to focus on consuming sources of higher-quality protein.”
“Our review of the science suggests that eggs are an ideal protein choice, plus, they are very affordable,” he added.
He also suggested that people should pay attention to when they eat their daily protein, especially the high quality protein. Most people eat protein in the evening, even though there is evidence that they would do better to eat it at breakfast. This brings significant benefits, including “stimulation of muscle protein synthesis and long-lasting satiety,” said Layman.
Some studies have shown that eggs are an effective part of weight loss management and satisfy hunger. A British Journal of Nutrution study, published online September 2008, suggested that eating two eggs for breakfast helped overweight people who were on a diet to lose 65 per cent more weight and feel that they had more energy compared to those who only had a bagel of equal size and calorie content.
“Egg Protein as a Source of Power, Strength and Energy.”
Layman DK, Rodriguez, NR
Nutr Today 44(1), pp43-48, Jan/Feb 2009.
Sources: Journal abstract, and press release on behalf of the American Egg Board and the Egg Nutrition Center (Edelman Public Relations via Eurekalert).
Written by: Catharine Paddock, PhD