If you’re still making the mistake of discarding egg yolks in favor of egg whites, it’s time to get with program. New research shows that whole eggs have a superior impact on protein synthesis, leading to a greater muscle building effect compared to egg whites alone.
In this study from the University of Illinois, researchers gave trained young men a meal of either three whole eggs or just the egg whites after two separate training bouts and then measured rates of muscle protein synthesis.
Both meals were matched for protein content, supplying 18 grams of protein and having equal quantity of specific amino acids, especially leucine, the most important amino acid for muscle building. Of course, the whole egg meal was higher in calories because it provided fat from the yolks, which were absent in the egg white meal.
Results showed that protein synthesis rates in the muscle were 40 percent higher after eating whole eggs than with the egg whites alone. This was surprising because the egg whites led to greater leucine availability to the muscle as well as higher peak leucine levels in the blood stream—two factors that are known to influence protein synthesis.
Researchers theorize that there is something about the “extra” nutritional components in the whole food eggs that lead to greater protein synthesis. For example, the egg yolk contains various nonprotein food components that may have as yet unidentified anabolic properties including the following:
Choline, a hard to get nutrient that plays a role in neurotransmitter production and impacts detoxification of fat from the liver.
Vitamins D and K, both of which impact protein synthesis and tissue repair in the body.
The antioxidants selenium and zeaxanthin, which are believed to reduce inflammation.
Protective lipids, including phosphatidic acid and DHA, which may modify pathways related to muscle building.
Other recent studies support the superiority of whole eggs versus egg yolks on health:
Incorrectly feared for their dietary cholesterol content, one study found that regular egg consumption can improve cholesterol levels. After increasing daily intake of eggs from zero to 3 a day over a 12 week period, subjects with high cholesterol had a less atherogenic profile, improved HDL function (the “good” cholesterol), and increased levels of enzymes that are protective against the hardening of the arteries, which leads to heart disease.
A second study of type 2 diabetics found that eating an egg breakfast improved inflammatory markers that are linked with heart disease to a greater degree than the gold standard “heart healthy” oatmeal breakfast.
Finally, an 8-week study found that having eggs for breakfast while on a diet produced significantly greater weight loss compared to having a bagel for breakfast. Subjects on the egg diet reported less hunger and greater restraint around food than a control group who were not dieting at all. They also reported having more energy and being less tired, as well as experiencing less pain.
Eggs are the gold standard when it comes to protein quality because they provide the ideal amino acid profile in a highly bioavailable form.
Whole eggs are a great source of difficult to obtain nutrients such as choline, selenium, and zeaxanthin.
The cholesterol in eggs have often been misrepresented as a risk factor for heart disease. More rigorous research shows there is no need to fear the cholesterol in eggs. Rather consuming eggs in their whole form has protective effects against cardiovascular disease.
Amino acids are often viewed as most important for building muscle. This research shows that other food components beyond dietary amino acids likely have a supporting role in maximizing muscle building.
The dietary fat in whole eggs likely plays an important role in maximizing the protein synthesis effect: You never find pure protein sources in nature. Rather protein-containing foods always provide dietary fat, which improves the body’s ability to “use” the protein for muscle recovery.
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