The benefits of egg protein for athletes: the evidence base

Egg protein is often mentioned as the “gold standard” of protein quality, but what exactly do studies say about its benefits for athletes? Our editorial team analyzed key acute experiments, training studies, and meta-analyses and explains where the evidence is strong and where it is lacking.

Why egg white is the “benchmark” in protein science

Historically, egg white was the reference point for assessing the quality of other proteins. Its amino acid profile matches human needs so well that in older methods, such as biological value, the egg was often taken as 100 conventional units.

Modern methods — PDCAAS and DIAAS, recommended by the FAO expert consultation (2013) — also classify egg white as high-quality. On the PDCAAS it receives the maximum score of 1.0 (Schaafsma, 2000), meaning it fully satisfies the need for essential amino acids taking digestibility into account.

For athletes this means that a serving of egg protein provides all the amino acids needed for muscle recovery and growth, without the need to combine it with other protein sources.

However, a high “quality rating” does not automatically guarantee better results in training studies. Therefore our editorial team separately examines what exactly experiments involving people have shown.

Acute studies: muscle protein synthesis

The most important of the acute studies is the work of Moore and colleagues (2009) in the American Journal of Clinical Nutrition. Young men received 0, 5, 10, 20, or 40 g of whole egg protein after a resistance leg workout. Muscle protein synthesis increased dose-dependently and reached a maximum at about 20 g. A dose of 40 g no longer provided a substantial additional effect but increased leucine oxidation.

These data became one of the main sources for the practical recommendation of 20–25 g of high-quality protein per intake for young people, which was later enshrined in the ISSN position papers (Jäger et al., 2017).

The study by van Vliet and colleagues (2017) compared whole eggs and egg whites with the same amount of protein (18 g). After resistance training, whole eggs stimulated muscle protein synthesis more strongly, although the concentration of amino acids in the blood was similar. The authors attribute this to yolk components — lipids, micronutrients, microRNAs.

It is important to understand the limitations of such work: it measures the short-term response over several hours, not long-term changes in muscle mass. Acute synthesis does not always accurately predict the result after months of training.

Training studies and meta-analyses

There are far fewer long-term studies of egg protein specifically than studies of whey. One of them is the work of Hida and colleagues (2012), in which female athletes received an egg white supplement or a carbohydrate control together with training for eight weeks. Strength increased in both groups; the authors found no substantial advantage of egg white in strength indicators, although the changes in blood amino acid concentrations differed.

A broader picture is provided by the meta-analysis of Morton and colleagues (2018), which combined 49 randomized studies of protein supplements. It showed that additional protein against the background of resistance training statistically significantly increases gains in lean mass and strength, and the benefit decreases after about 1.6 g of protein per kg of body weight per day.

This meta-analysis found no clear advantage of any single protein source if the total daily amount is sufficient. That is, egg protein probably works the same way as other complete proteins, and the main factor is the total protein intake.

So the evidence base for egg protein rests primarily on data about its quality and acute studies of synthesis, while long-term results are confirmed through general patterns for protein supplements.

Practical advantages for athletes

In addition to the data on muscles, egg protein has a number of practical advantages that make it a useful tool in certain situations:

• Absence of lactose— suitable for people with lactase deficiency.
• An alternative in case of allergy to dairy proteins— if there is no egg allergy.
• Low calorie content and minimal fat— convenient during cutting.
• Medium absorption rate— a universal choice for any time of day.
• Culinary flexibility— can be used in baking, pancakes, omelets.

For athletes seeking to reach the recommended 1.4–2.0 g of protein per kilogram of body weight per day (Jäger et al., 2017), egg protein can be a convenient way to make up the needed amount without excess fat.

In sports with weight categories, where calorie control is important, the high protein content per serving is an advantage.

At the same time, compared with whey protein, the price per gram of protein is usually higher, and the taste is more specific. Therefore, for people without dietary restrictions, the choice between them often comes down to personal preference.

Limitations of the evidence base

Our editorial team considers it necessary to honestly outline the limits of the available knowledge. First, the number of randomized training studies with egg protein specifically is small, and the samples in them are, as a rule, small.

Second, most acute studies were conducted on young men. For women, older people, and elite athletes, the protein requirement per intake may differ; for example, older people often need a larger dose for maximum stimulation.

Third, the results of studies with whole eggs cannot be automatically transferred to egg white powder, which has no yolk.

Finally, some studies in the field of sports nutrition are funded by manufacturers, which requires critical reading. However, for egg protein this factor is less pronounced than for some other supplements.

Editorial conclusions

Egg protein has a solid theoretical basis: the maximum PDCAAS, a complete amino acid profile, and a proven ability to stimulate muscle protein synthesis with a plateau at about 20 g per intake in young men.

There are few direct long-term studies, but meta-analyses of protein supplements generally confirm their benefit for mass and strength against the background of training.

The main thing for the result is a sufficient daily amount of protein, and egg protein is one of the high-quality ways to provide it, especially for people with lactose intolerance.

We also recommend our articles “Egg protein: what it is and how it works,” “How to take egg protein,” and “Side effects of egg protein.”

References

1. Moore DR, Robinson MJ, Fry JL, et al. Ingested protein dose response of muscle and albumin protein synthesis after resistance exercise in young men. Am J Clin Nutr. 2009;89(1):161–168.
2. van Vliet S, Shy EL, Abou Sawan S, et al. Consumption of whole eggs promotes greater stimulation of postexercise muscle protein synthesis than consumption of isonitrogenous amounts of egg whites in young men. Am J Clin Nutr. 2017;106(6):1401–1412.
3. Hida A, Hasegawa Y, Mekata Y, et al. Effects of egg white protein supplementation on muscle strength and serum free amino acid concentrations. Nutrients. 2012;4(10):1504–1517.
4. Morton RW, Murphy KT, McKellar SR, et al. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. Br J Sports Med. 2018;52(6):376–384.
5. Jäger R, Kerksick CM, Campbell BI, et al. International Society of Sports Nutrition position stand: protein and exercise. J Int Soc Sports Nutr. 2017;14:20.
6. Schaafsma G. The protein digestibility-corrected amino acid score. J Nutr. 2000;130(7):1865S–1867S.
7. FAO. Dietary protein quality evaluation in human nutrition: report of an FAO Expert Consultation. FAO Food and Nutrition Paper 92. Rome: FAO; 2013.
8. Phillips SM, van Loon LJ. Dietary protein for athletes: from requirements to optimum adaptation. J Sports Sci. 2011;29(Suppl 1):S29–S38.