Why does my body not tolerate onions?
If onions are causing you problems, you are not alone! Even completely healthy people often suffer from flatulence, stomach noises, diarrhea or foul-smelling gases after consuming onions. This is due to fructans , which are not only found in onions, but in many other foods such as garlic, leek, pistachios, broccoli, artichokes, wheat, chicory or Brussels sprouts.
Fructans are fermentable multiple sugars that pass through the small intestine almost undigested. Only in the large intestine are they broken down by intestinal bacteria through fermentation processes . In addition, fructans draw water into the intestines. Flatulence, altered bowel movements and diarrhea can result.
It is difficult to differentiate between an intolerance to onions and a completely normal reaction to fructans. An allergy to onions, on the other hand, is very rare.
How is an allergy to onions manifested?
In Europe, wheat, milk, egg, soy, nuts and seafood are the main allergens in food. The immune system, which is misdirected in the event of an allergy, identifies them as harmful substances and fights them. The body’s reactions can be easy, but they can also be difficult.
Many allergy symptoms – in contrast to food intolerance – express themselves outside of the digestive tract: the skin reddens, the mucous membranes swell, both of which can be accompanied by itching. This is sometimes accompanied by an allergic runny nose. In extremely severe cases, allergy sufferers experience anaphylactic shock , which can lead to unconsciousness and even cardiovascular arrest. This reaction is very rare – also because those affected usually know about their severe allergy and have appropriate, quickly-acting medication with them.
An allergy can manifest itself through cross-reactivity : Not only does the allergen itself trigger symptoms, but also contact with substances that contain similar types of proteins. In the case of onions, these can not only be onion plants such as garlic, leeks or chives, but also other plants from the amaryllis family such as tulips, daffodils or lilies.
What is the difference between an allergy and an intolerance?
While an allergy is mediated immunologically – the immune system identifies in itself harmless substances as dangerous and fights them – the body has problems processing food in the case of an intolerance or intolerance. The body then usually lacks enzymes to break down certain ingredients.
The most common intolerances include intolerance to lactose, fructose , sorbitol or an increased sensitivity to gluten or wheat. As we have seen, the fructans contained in onions are also often poorly tolerated.
Some typical symptoms of food intolerance are:
- stomach pain
- Belly noises
- Abdominal press
We have summarized detailed information for you to differentiate an allergy from an intolerance .
The symptoms mentioned above can also occur in the event of an allergy. You should therefore always consult a doctor to clarify the causes of your symptoms .
How can I get tested for an intolerance or allergy?
If you regularly suffer from allergy symptoms or indigestion, you should discuss these with a doctor first. You can have yourself tested for allergies by a specialist in allergology – this can be a dermatologist, ENT doctor or internist with appropriate training.
First, the doctor will interview you about your symptoms, diet, and lifestyle, and perform a physical exam. An allergy can often be diagnosed with a skin test (prick test) or blood test (IgE test). During the skin test, the doctor scratches the skin on the forearm and drips an allergenic solution onto it. If there is a reaction, this indicates an allergy. The blood test measures the level of the antibody immunoglobulin E in the blood. An increased IgE level can indicate an allergy, but also occurs as an immune response to parasites.
In order to identify intolerance, the doctor may suggest an elimination diet in which you remove certain foods from the menu for a while and observe how this affects your symptoms. If you have kept a food diary for a few days or weeks, bring it with you to your appointment.
What can I do if I have an onion intolerance?
In the case of an onion allergy, it makes sense to avoid onions and also to avoid contact with other plants from the amaryllis family if these cause symptoms (cross-reactivity, see above). If that doesn’t work and you develop allergic symptoms, so-called antiallergic drugs (e.g. antihistamines) can help . They relieve allergic rhinitis, skin swelling and reddening and itching. In an anaphylactic reaction, on the other hand, epinephrine is the drug of choice.
Depending on the level of suffering, it may be advisable to remove onions from the menu even if you have an intolerance. If you’ve ever eaten too many onions, you can try using home remedies for abdominal pain and cramps or home remedies for nausea relief.
Often times, traditional recipes that use a lot of onions or other flatulent ingredients contain certain spices. Some of these spices are said to improve not only the taste but also the digestibility. Caraway seeds are used as a remedy for flatulence. So it’s no wonder that the classic onion cake is often seasoned with it. However, the effect of the spices is usually limited.
What are the alternatives?
If you can’t tolerate fresh onions, you can try the processed variant:
- pickled (e.g. in vinegar or oil)
This often makes onions easier to digest. It’s also worth trying different types of onion. Red onions, for example, are often milder than normal table onions.
If you want to replace onions completely, it is best to take a look at the closest relatives of the onion : shallots, but also leeks, garlic or wild garlic sometimes give your dishes the flavor they need. But be careful, these foods often cause problems with an onion allergy or intolerance! If that is the case for you, rely on the following alternatives:
- Asant: The spice, which is still little known in Germany, is an ideal alternative for anyone who cannot tolerate garlic and onions. Because of its strong smell, asante is also called the devil’s dirt. When cooked, it then develops a pleasant aroma of garlic and onion.
- Fennel: When cooked, the tuber tastes slightly like onion. Fennel is also available dry, which makes it even easier to process.
- Celery makes for a pleasant bite, for example in a tuna salad. Celery can also be a good substitute for onions when cooked, for example in soups.
- Radish: Radish provides the necessary spiciness in cold dishes.
Does a diet help with intolerance?
If you have frequent digestive problems such as stomach pressure, nausea, cramps, diarrhea, or gas after eating, the FODMAP diet may help. FODMAPs, which also include the fructans in onions, are fermentable single, double and multiple sugars as well as sugar alcohols, which are initially considered to be very healthy: These are soluble fibers that our valuable intestinal bacteria like to use.
Unfortunately, they can also cause problems – for example with irritable bowel syndrome. Gradually switching to a low-FODMAP diet may help people manage the bloating and nausea associated with irritable bowel syndrome . Because FODMAPs are found in a number of healthy foods and support an intact intestinal flora , you shouldn’t go on an FODMAP diet lightly. You should also know when an FODMAP diet makes sense and what you should be aware of.
What to do if you have an onion intolerance?
Onions cause symptoms such as gas, stomach pain, cramps, diarrhea or nausea in many people. An allergy , which is often expressed through contact not only with bulbs, but also with related plants such as lilies or tulips, is in most cases not behind it.
It is more likely that you suffer from an intolerance or a completely normal reaction to the rather difficult to digest onions. The onion contains fructans (fermentable multiple sugars), which can lead to diarrhea, flatulence and foul-smelling gases even in completely healthy people.
If you have to or want to do without onions, there are a few alternatives : fennel, celery, radish and, above all, asante can be good substitutes. A strict diet – such as the FODMAP diet – in which many healthy foods are removed from the menu, on the other hand, is not generally recommended.
If you suffer from another intolerance, you can of course also find out more about potato intolerance and Co. from us