Do Boiled Eggs Cause Gas? Hard Boiled + More
Boiled eggs can cause gas, and sulfur is the usual reason. Eggs carry two sulfur-rich amino acids, methionine and cysteine, and those are what give egg wind its particular smell. For some people the cause is different again, an intolerance or an allergy to egg protein rather than the sulfur, and those two are worth telling apart.
Below is what the sulfur actually does, where tolerance and allergy differ, and why boiled eggs seem to bother some people more than scrambled.
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.
Common Questions About Boiled Eggs And Gas
Do hard boiled eggs cause more gas than soft boiled?
Researchers have not settled this one. Both carry the same sulfur-rich amino acids, and no study has compared the two for gas specifically, so anything definite you read on it is going beyond the evidence.
Why does egg gas smell so bad?
The sulfur. Methionine and cysteine are two of the amino acids in egg protein that contain sulfur, and sulfur compounds are what your nose picks up. The smell is about the type of gas rather than the amount of it, which is why a small serve of eggs can be more noticeable than a large plate of something else.
Is it the yolk or the white that causes gas?
Both carry protein, so both contribute, and the sulfur amino acids are present across the egg. If you suspect one part over the other, trying them separately for a while is more reliable than guessing, and worth mentioning to a GP if the reaction is strong.
What is the difference between an egg intolerance and an egg allergy?
An allergy is an immune response to egg protein and can produce symptoms well beyond the gut. An intolerance is a digestive difficulty with no immune reaction behind it. They can feel similar around the stomach, which is exactly why a proper diagnosis matters rather than self-identifying with one.
Why do scrambled eggs seem easier than boiled?
There is no research showing scrambled eggs cause less gas than boiled, so this may well be portion, what they are cooked with, or what else is on the plate. One study did find boiled eggs rank higher than scrambled for carotenoid digestibility, though that is a different question from gas.
Are poached eggs easier to digest?
One study in older adults with gut issues found poached eggs supplied more protein than an omelette, while the omelette gave better vitamin D3 availability. Whether the cooking method itself made the difference is an assumption rather than a finding, so treat it as worth trying rather than established.
Does eating eggs more slowly help?
It can help a little, since eating quickly means swallowing more air, and that adds to whatever the food is doing. It will not change the sulfur side of it.
How many eggs is a reasonable serve?
This depends on you rather than on a fixed number. If two eggs give you trouble and one does not, that is your answer, and it is more useful than any general guideline. A dietitian or GP is the right person to ask if you are cutting eggs out of your diet entirely.
When should I get egg-related gas looked at?
Persistent or constant gastrointestinal discomfort after eating, egg or otherwise, is worth a doctor's appointment. The same goes for anything that comes with pain, a rash, swelling or trouble breathing, which are reasons to seek help promptly rather than adjust a recipe.
Where To Go Next
Telling an intolerance apart from an ordinary reaction to a food is the part most people get stuck on, and it is the ground Trish Tucker-May covers on her page as the nutritionist behind the food side of this site.
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