Onions and IBS Don’t Mix – Avoid Onions

As a person with Irritable Bowel Syndrome (IBS), I often tell people I avoid the big two: Onions and garlic. If you have IBS, it is very likely that consuming onions and garlic or anything cooked with it will cause you digestive issues. Therefore, you should avoid onions as much as possible.

Your exact sensitivity to anything in the onion family will really depend on your digestive system. For me, onions and garlic immediately trigger IBS symptoms within 12 hours.

Take a look at the low-FODMAPs diet especially if you were recently diagnosed with IBS. It contains quite a complete list of things you should and should not eat. From my experience, the information was life-changing as I figured out what works and what doesn’t work for me. I immediately started to avoid onions and that has really helped a lot, to say the least.

What is the onion family?

Anything in the onion family is not IBS-friendly. This unfortunately includes some very commonly used items in cooking, at restaurants, and in prepared or manufactured goods.

The onion family includes leeks, chives, red onion, white onion, yellow onion, green onion, shallots, and garlic. It is important that you avoid onions and anything in the onion family.

The big problem is that items in the onion family are very widely used at restaurants and in processed foods. I am willing to bet that you like cooking with onions and garlic too. I mean, who doesn’t like a chopped up onion in pasta sauce or garlic stir fry with beef? Yum! I used to add chopped onions in everything. Onions in chicken soup makes the soup sweeter and healthier. Garlic enhances the flavors of everything and I would eat garlic with sausages. Anything in the onion family also provide unique nutrients and flavors.

Unfortunately, your IBS interferes with the proper digestion of onions.

Onions and IBS Don't Mix - Avoid Onions

Why those with IBS should avoid onions

Many people with IBS have digestive systems that cannot tolerate fructans.

Onions and garlic happen to be high in fructans. Artichoke (globe and Jerusalem), rye (grain and bran), asparagus, and barley kernels also happen to have fructant content as well. Another big food category with fructans is wheat. That is one of the reasons why those with IBS tend to avoid wheat and go gluten-free instead. Personally, I avoid onions and garlic, as well as all wheat products such as pasta and bread.

Food that cause gas is also not helpful for those with IBS. Since onions ferment in our digestive tract, it causes gas and that leads to IBS symptoms as well. Food such as cabbage, broccoli, artichoke, and asparagus will also cause gas.

What are fructans?

In order to understand why we should avoid onions, we have to understand what are fructans.

Fructans are large molecules, or polymers, of fructose. Fructose is a sugar found in many plants. Fructans function as large storage units for carbohydrates that plants use to power themselves. Essentially, fructans are carbohydrates that are fermentable once it reaches your stomach.

Humans can’t quite digest fructans that well, and that is why they ferment in our digestive system. For a healthy person with a normal digestive system, fermented food in the digestive tract is not a problem and actually a normal process of digestion. However, for a person with an IBS digestive tract, fermented food cause diarrhea or constipation.

The indigestion of fructans cause an IBS digestive system to be over active. Since timing is very important for proper digestion and good bowel movements, this further causes an IBS gut distress. Therefore, it would be smart to avoid onions and garlic as a general rule.

Say “no onions” at restaurants

Restaurants often use onion powder, onion juice, crushed garlic, garlic oil, and other ingredients in the onion family. Just by reading the menu isn’t enough to determine what exact ingredients they would use to make the dish. Restaurant menus usually only highlight the main ingredients and you will likely not see onion or garlic added to the dish until after you taste it. By that time, it’s too late.

At restaurants, I tell the waiter or waitress that I have a light allergy to onions and garlic. I have noticed that simply saying “I don’t like/can’t take garlic or onions” is not enough. They sometimes don’t take it seriously and I end up with digestive issues from the fructans in garlic or onions again.

A light allergy would simply alert the kitchen to either avoid the ingredient or substitute it with something else. If you inform them, most kitchen staff will prepare your food differently as they are trained on how to handle food allergies.

Avoiding onions and garlic should be easy when you eat out. Just speak up!

Look for onions in processed/manufactured food ingredients list

After I developed IBS, I started to be more aware of exactly what I am eating every day. I also learned how prevalent onions and garlic are in ready-to-eat, processed, or manufactured food.

It is also only after having IBS that I started reading the ingredients list on product panels, which sometimes run over 50 for some items!

If you have IBS, please develop a habit in reading the ingredient lists. No matter how long or complicated they may seem to you. Usually towards the middle or end of the list, you may find onion powder, onion, garlic, garlic oil, or some variant of the onion family on there. If you see such a thing, it may be wise to avoid the product.

It is a legal requirement for manufacturers to list product ingredients by amount, from greatest to least. For example, if you purchase almond milk, then usually you will see water followed by almonds. Perhaps some vitamins and salt added. Salt wouldn’t appear first in the ingredients list unless you’re buying sea salt.

After I learned that I have IBS, I unintentionally continued to consume food that had onion and garlic ingredients. For example, a favorite of mine was a slow-cooked lamb shank with mint sauce. It was such a convenient and delicious product. Unfortunately, one of the ingredients listed at the end was onion. Since the ingredient is at the end of the list, I didn’t think much of it. However, I would get digestive issues a few hours later. Therefore, I made up a general rule to just avoid onions going forward.