Whole eggs or egg whites?

Most people throw away the egg yolks and consume only egg whites as the yolks were once thought to affect heart health due to its high cholesterol levels.

Egg whites are also consumed to maximise the dietary intake of protein from eggs.

Protein is the buzzword in the modern diet and research is showing that we need more of it than what we once thought to maintain our health.

The researchers found that ingesting either whole eggs or only egg whites gave the same amount of dietary amino acids in the blood. About 60 to 70 percent of the amino acids were available in the blood to build muscle protein.

But throwing out the egg yolks and consuming only the whites to increase protein intake is counterproductive as the yolks also contain protein along with other key nutrients and components not present in the egg whites, according to researchers from the University of Illinois.

In a study, 10 healthy young men, with an average age of 21 years, participated in a single bout of resistance exercise. They then ate whole eggs or egg whites containing 18 grams of protein.

Researchers administered infusions of two stable-isotope-labelled amino acids – leucine and phenylalanine to the participants.

This allowed the researchers to maintain and track amino acid levels in the participant’s blood and muscles.

The eggs for the study were isotopically labelled with leucine which allowed for the tracking of where the food-derived amino acids ended up in the participants after they consumed them.

The researchers took multiple blood samples and biopsy samples to assess how egg-derived amino acids were appearing in the blood and in the protein synthesis in muscles before and after resistance exercise.

The researchers found that ingesting either whole eggs or only egg whites gave the same amount of dietary amino acids in the blood. About 60 to 70 percent of the amino acids were available in the blood to build muscle protein.

Generally, the amount of amino acids in the blood gives an indication of how strong a food source is for muscles building. In this case, both egg whites and whole eggs provide the same amount of protein content.

But when the researchers directly measured protein synthesis in the muscle, they found that ingestion of whole eggs after resistance training resulted in greater muscle-protein synthesis – 40 percent greater – than after ingesting only egg whites.

Whole eggs also contain 17 grams of fat (egg whites don’t contain fat) which may contribute to the body utilising the protein in the muscles more effectively.

Studies have shown that simply adding fat to an isolated protein source in diet after exercise does not boost protein synthesis.

This shows that consuming a whole egg which contains the same amount of protein as egg whites but is nutrient dense is more beneficial to our muscles.

Forget separating egg yolks from the whites and create some delicious brekkie options using whole eggs for maximum benefits to your muscles.

Source: The American Journal of Clinical Nutrition