Egg Protein vs Casein: What to Choose and for Whom

When a person has already decided that whey does not suit them or a protein is needed for other tasks, two candidates often end up in the final - egg white and casein. Our editorial team has prepared a practical overview: in which situations it is more logical to choose one, in which the other, and whether the two can be combined.

For what task are you choosing a protein

Protein is a tool, and the choice of tool depends on the job. One person needs to close the night-time break in protein supply, another to get a lactose-free animal protein, a third to make a filling snack during a diet.

Casein by its nature supplies amino acids over a long time, so it works best where there is a long gap between meals. Egg white is absorbed faster and is suitable for universal use throughout the day, including after workouts.

The second thing that determines the choice is allergies and tolerance. For people with a milk allergy casein is unsuitable in any form; with an egg allergy, accordingly, egg protein is excluded.

The third is taste, texture and price. Egg protein is usually more expensive than casein and has a more specific taste; casein gives a thick drink, which some people like and others do not.

1. Determine the main task: night-time intake, snack, post-workout intake.
2. Take into account allergies and the reaction to lactose.
3. Assess the budget per 25 g of protein and the desired texture.

When casein is better

Before sleep. This is the best-substantiated use of casein. The studies by Res and colleagues (2012) and Snijders and colleagues (2015) showed that taking casein before sleep improves night-time muscle protein synthesis and, in a long-term programme, is associated with a greater increase in mass and strength. The review by Trommelen and van Loon (2016) summarised these data.

During a diet for hunger control. The thick texture and slow digestion create a feeling of fullness for longer. A casein "pudding" with a spoonful of cocoa often replaces a sweet dessert in people at a calorie deficit.

As a long snack between meals, when the next normal meal is only in a few hours' time - for example, during a working day.

For people who like a milky taste and tolerate dairy products well. In such cases casein often turns out to be more advantageous in price than egg white.

When egg protein is better

With an allergy to cow's milk protein or pronounced lactose intolerance. Egg protein is one of the few animal proteins in powder completely free of dairy components.

After a workout, when it is desirable to get a relatively faster supply of amino acids than casein provides, but whey for one reason or another is unsuitable.

For baking and cooking: egg white whips well, stabilises the structure and helps to make protein pancakes, muffins and meringues without adding whole eggs.

For people who follow diets without dairy products - for example, paleo eating - or who limit dairy products for other reasons.

How to fit protein into your day

A protein supplement should complement the diet, not replace food. First calculate your daily requirement - for people who train, ISSN recommends 1.4-2.0 g of protein per kilogram of body weight - and determine how much of it is covered by ordinary meals.

Then distribute protein across 3-5 intakes. Casein logically goes in the evening, egg white at breakfast, a post-workout intake or a snack.

Combining both proteins is entirely possible: they do not "compete" with each other but simply perform different roles. It is only important not to exceed a reasonable daily amount of protein without need.

The ISSN position on nutrient timing (Kerksick et al., 2017) recognises protein intake before sleep as a useful strategy, but emphasises that the total daily amount remains the priority.

Quality criteria when buying

For casein, clarify the form: micellar casein retains the natural structure and is absorbed more slowly, caseinate dissolves better but may behave differently. The manufacturer should indicate exactly what the product contains.

For egg protein, pasteurisation and the absence of added free amino acids are important. A quality product contains about 80% protein or more; flavourings may slightly lower this figure.

Compare the price per 25 g of protein, not per tub. Egg protein is usually more expensive, so the extra cost should match a real need - an allergy or dietary restrictions.

Athletes who undergo doping control should choose products with independent certification, as the IOC consensus on food supplements advises (Maughan et al., 2018).

• A clearly stated protein form and its proportion per serving.
• The amino acid profile on the label.
• Labelling of allergens and possible traces.
• Laboratory quality certificates.

Editorial conclusions

Casein is the choice for intake before sleep, prolonged satiety and those who tolerate dairy products well.

Egg protein is the choice for those allergic to milk, people with lactose intolerance, for post-workout intake without whey and for cooking.

Both proteins can be combined within the day - the main thing is that the total amount of protein matches your needs.

We also recommend our articles on micellar casein and caseinate, on protein baking and on the daily protein requirement for different goals.

References

1. Res PT, Groen B, Pennings B, et al. Protein ingestion before sleep improves postexercise overnight recovery. Med Sci Sports Exerc. 2012;44(8):1560–1569.
2. Snijders T, Res PT, Smeets JS, et al. Protein ingestion before sleep increases muscle mass and strength gains during prolonged resistance-type exercise training in healthy young men. J Nutr. 2015;145(6):1178–1184.
3. Trommelen J, van Loon LJC. Pre-sleep protein ingestion to improve the skeletal muscle adaptive response to exercise training. Nutrients. 2016;8(12):763.
4. 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.
5. Kerksick CM, Arent S, Schoenfeld BJ, et al. International Society of Sports Nutrition position stand: nutrient timing. J Int Soc Sports Nutr. 2017;14:33.
6. Maughan RJ, Burke LM, Dvorak J, et al. IOC consensus statement: dietary supplements and the high-performance athlete. Br J Sports Med. 2018;52(7):439–455.