Side effects of egg protein

Egg protein is considered one of the safest sources of protein, but it too can cause unwanted reactions — from unpleasant bloating to serious allergy. The editors have examined which side effects are actually described, why they occur and how to avoid them.

General safety profile

Egg protein is dried and pasteurized egg white, that is, a product humankind has consumed for millennia in ordinary food. Therefore for most people it is safe, and its side effects mostly come down to digestive reactions and, more rarely, allergy.

At the same time the concentrated form changes the picture: a serving of powder can contain as much protein as 6–8 egg whites, and it is consumed quickly. This increases the likelihood of GI discomfort and makes allergic reactions in sensitive people potentially stronger.

The editors consider the side effects in order from the most common to the most serious, and also explain who should be especially attentive to this product.

The diagram shows: the most common reactions are digestive and mild, while the most serious — allergic — occur less often but require the greatest attention.

Digestive reactions: bloating, gas, nausea

The most common complaints about egg protein are bloating, increased gas formation and a feeling of heaviness. Egg white is rich in sulfur-containing amino acids — methionine and cysteine. The part of them that is not absorbed in the small intestine is fermented by the microflora of the large intestine with the formation of sulfur compounds, which give the gas its characteristic unpleasant smell.

The intensity of these symptoms depends on the dose per intake, the speed of consumption and the overall composition of the diet. A large serving of protein drunk on an empty stomach in a minute more often causes discomfort than the same amount spread across meals.

Another cause of digestive complaints is not the protein itself but the additives in the product: sugar alcohols (erythritol, sorbitol, maltitol), thickeners, inulin. They can cause bloating and loosening of the stool, especially in people with irritable bowel syndrome.

Some users note nausea associated with the specific taste and smell of egg protein. Here it helps to choose products with good-quality flavorings or to use the powder in dishes — pancakes, omelets, baked goods.

Egg allergy: the main serious risk

Egg allergy is one of the most common food allergies in children; in most of them it passes with age, but in some it persists into adulthood (Caubet, Wang, 2011). The main allergens are contained precisely in the egg white: ovomucoid, ovalbumin, ovotransferrin and lysozyme.

Ovomucoid is especially important: it is resistant to heating and digestive enzymes. Therefore pasteurization, which makes egg protein safer microbiologically, does not eliminate its allergenicity. For people with an egg allergy, egg protein is contraindicated.

The manifestations of allergy vary from mild — itching in the mouth, urticaria, runny nose — to severe: swelling of the larynx, bronchospasm, a drop in blood pressure, anaphylaxis. Severe reactions require emergency medical care.

For people who have atopic dermatitis, asthma or other allergies, the editors advise trying a new protein with caution: start with a small amount and monitor the reaction. If there was ever a reaction to eggs in childhood, it is worth consulting an allergist before taking it.

Other possible risks

Biotin and avidin.Raw egg white contains avidin, which binds biotin (vitamin B7) and can cause its deficiency with prolonged consumption of large amounts of raw whites. Pasteurization and heating largely inactivate avidin, so for a quality powder this risk is minimal.

Microbiological safety.Raw eggs can be a source of salmonella. A pasteurized powder from a reliable manufacturer practically eliminates this risk. By contrast, a "homemade" replacement of protein with raw eggs is dangerous and less effective: the digestibility of raw white is much lower (Evenepoel et al., 1998).

Kidneys.The systematic review and meta-analysis by Devries et al. (2018) found no worsening of kidney function in healthy adults on a high-protein diet. However, for people with chronic kidney disease the amount of protein is limited by a doctor, and any protein without agreement is undesirable.

Sodium.Dried egg white contains a noticeable amount of sodium. People with hypertension or on a salt restriction should take this into account in their daily diet.

Cholesterol.Whole-egg products contain the cholesterol of the yolk. For most people dietary cholesterol is less important than saturated fats, but patients with hypercholesterolemia had better discuss their diet with a doctor.

How to reduce the likelihood of side effects

Most of the troubles with egg protein can be prevented by simple steps:

• start with half a serving and gradually increase;
• divide the daily amount into several intakes of 20–30 g;
• mix with water or a plant-based drink and drink slowly;
• choose products without sugar alcohols if you are prone to bloating;
• buy only pasteurized products with a transparent composition and allergen labeling;
• at any signs of allergy, stop taking it immediately.

It is also useful to watch the overall diet: a sufficient amount of fiber, fluid and diverse sources of protein reduces the load on the intestine.

If bloating persists even at small doses, you can try another source of protein — whey isolate, hydrolysate or plant proteins.

In the case of chronic kidney, liver or cardiovascular disease, it is worth consulting a doctor before taking it.

Editorial conclusions

Egg protein is safe for most healthy people. The most common side effects — bloating, gas and nausea — are dose-dependent and usually easily corrected.

The main serious risk is egg allergy. Heat-stable ovomucoid is not destroyed by pasteurization, so for people with an allergy the product is contraindicated.

For healthy kidneys a high-protein diet is not harmful according to the available data, but in chronic kidney disease the amount of protein is determined by a doctor.

Read also our materials "Egg protein: what it is and how it works", "How to take egg protein" and "The benefits of egg protein for athletes".

References

1. Caubet JC, Wang J. Current understanding of egg allergy. Pediatr Clin North Am. 2011;58(2):427–443.
2. Evenepoel P, Geypens B, Luypaerts A, Hiele M, Ghoos Y, Rutgeerts P. Digestibility of cooked and raw egg protein in humans as assessed by stable isotope techniques. J Nutr. 1998;128(10):1716–1722.
3. Devries MC, Sithamparapillai A, Brimble KS, Banfield L, Morton RW, Phillips SM. Changes in kidney function do not differ between healthy adults consuming higher- compared with lower- or normal-protein diets: a systematic review and meta-analysis. J Nutr. 2018;148(11):1760–1775.
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. Schaafsma G. The protein digestibility-corrected amino acid score. J Nutr. 2000;130(7):1865S–1867S.
6. 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.