Do Boiled Eggs Cause Gas? Hard Boiled + More

Eggs are regarded as an almost-complete food item because they only lack vitamin C in order to be nutritionally complete. So why does it seem like they cause gas?

Boiled eggs contain methionine and cysteine, which can lead to gas. A person’s tolerance and allergic reaction to proteins in the boiled egg could also be the cause. 

What are the differences between tolerance and allergy, and do methionine and cysteine make boiled eggs harder to digest? Discover the answers below!

Do Boiled Eggs Give You Gas or Bloating?

Eggs contain sulfur-rich substances called methionine and cysteine, which can lead to gas and bloating in some people. Researchers have yet to determine whether hard-boiled eggs or soft-boiled eggs cause more gas. 

Why Do Boiled Eggs Give You Gas?

There are three possible causes of gas, bloating, or excessive flatulence after eating boiled eggs. It may be because of the egg’s sulfur content, or it could be because a person is intolerant or allergic to egg proteins.

Let’s think back to our high school chemistry class and remember that there are 20 amino acids (proteins). Out of the 20, four contain sulfur, and two of these are added to proteins: namely methionine and cysteine (source: The Journal of Nutrition). 

Generally, proteins contain 3%–6% of sulfur amino acids. Cysteine can be made by our bodies, while methionine cannot. This can be provided through our diets (source: Nutrition and Metabolism).  

Eggs are rich in methionine and especially in cysteine (source: Nutrition and Metabolism). These sulfur-containing proteins can cause some pretty smelly gas (source: BBC UK, Bad Gut).

This can be supported by gas chromatography research. A study was conducted to check the odor of eggs in three different stages: freshly boiled, decaying/intermediate, and decayed. 

Results showed that sulfur was most present in freshly boiled eggs (source: Microchemical Journal). 

Another cause of passing gas from boiled eggs might be because of egg intolerance or egg allergy. These two are not the same but will be discussed in conjunction because one can be mistaken for the other. 

Protein intolerance happens when there is an adverse effect when ingesting foods with proteins (source: Protein Intolerance). You have an egg intolerance to boiled eggs when your gut can’t digest the proteins in the egg yolk and/or egg white of the egg. 

Whenever food enters the body, the small intestines produce proper enzymes to digest them. If your body can’t produce the right enzymes for the proteins present in the egg, it will not be digested and will stay in the colon for quite some time – long enough for bacteria to surround it and cause digestive distress such as gas, bloating, diarrhea, and other common symptoms.

Although immunological (allergic reaction) mechanisms can also be considered protein intolerance, most people distinguish between the two (source: Protein Intolerance).

If you have an egg allergy, your immune system sees the proteins in the egg as potentially harmful, so it sends immune responses to destroy these potentially dangerous compounds. This causes abdominal discomfort like gas and bloating.

Finally, passing gas after eating a boiled egg could also be linked to improper storage conditions.

Eggs are a great source of nutrients. Sulfur itself is one of the most abundant elements in the body and is involved in many of its important processes (source: Nutrition and Metabolism).  

However, if you always pass gas, are always bloated, or have any persistent abdominal pain when defecating after eating boiled eggs, we recommend going to your doctor to get to the root cause. 

Are Boiled Eggs Hard to Digest?

Boiled eggs are not hard to digest. In fact – quite the opposite. Boiled eggs are often given to those recovering from nausea or stomach viruses due to their digestibility (source: MedicalNewsToday).

In a study, the Protein Digestibility Corrected Amino Acid Score (PDCAAS) was used to measure the digestibility of protein-rich foods. Eggs scored a maximum of 1. 

In the same study, another method called digestible indispensable amino acid score (DIAAS) was used to measure the digestible essential amino acids in a protein compared to a control or reference.

Results showed that boiled eggs scored 113. The higher the number (for both of the methods) the more digestible the food is (source: Foods). 

Moreover, in my experience, hard-boiled eggs are sometimes given to patients who require soft diets or mechanical soft diets in the hospital. This is because they are easy to chew, swallow, and digest. The body doesn’t have to spend too much effort in breaking them down. 

Why Boiled Eggs Might Give You Gas When Scrambled Eggs Don’t

There are no scientific studies or research as to whether boiled eggs might cause gas and scrambled eggs don’t. The only study we can find available about boiled eggs compared to scrambled eggs is their carotenoid digestibility. In this regard, boiled eggs rank higher than scrambled eggs (source: Journal of Agricultural and Food Chemistry). 

Another study was conducted on the digestibility of amino acids and the bioaccessibility of vitamins A and D₃ in the elderly with issues in their gut. In this study, poached eggs supplied more protein than an omelet. The omelet, on the other hand, showed to supply higher bioaccessibility of vitamin D₃ (source: Journal of Agricultural and Food Chemistry).

Although poached eggs and boiled eggs are different, the method of cooking (boiling water in this case), may have made the difference. However, this is only an assumption.

Remember, if you feel constant or persistent gastrointestinal discomfort after eating any food, consult your doctor. We hope this article helps!