Nutrition Facts of Onions: The good the bad and the IBS


Praised for their immune enhancing properties, but how much do we really know about the nutrition facts of onions? Should they be a staple in our diets or could they be doing more harm than good?

Lets dig a little deeper.

Onions (Allium cepa), from the classic large bulb vegetable to its many relations of shallots, scallions, leeks and even chives. All have a vast array of health benefits and the ability to greatly enhance the flavour of many savoury dishes; so it is no wonder that throughout our cookbooks and all of Restorative Wellbeing, there is an inclination to encourage the use of onions.

vegetables harvest fresh basket
Photo by Markus Spiske on

However, although all looks great on paper, our bodies don’t all work the same. As many benefits there are for people to eat onions, there are also downsides. Onions are the perfect highlight of how important it is to listen to your body. Our bodies are the perfect tool to guide us to heal; without that connection, the healing will be un uphill struggle.

To help you figure out if using onions in your diet is of benefit or harm to your overall health, we are going to break it down simply into the benefits and downfalls.


  • Nutrient Dense. Source of vitamin C and vitamin B6, and even small amounts of iron and magnesium
  • High in Antioxidants. Including, fisetin, quercetin.
  • Lowers risk of stomach and colorectal cancers.
  • Blood sugar control. Due to flavonoid antioxidants.
  • Boost bone density. Due to quercetin antioxidants protecting from free-radical bone damage.
  • Antibacterial properties. – creating a poor environment for harmful bacteria to live. Making it useful as a tropical treatment for fungal and bacterial infections.
  • Prebiotics – essential for maintaining good gut health.


  • Aggravates IBS – A common trigger for IBS and a no go for FODMAP diet followers.
  • Allergic reactions – Not a common allergen but still one to look out for.
  • Eye irritation – Caused by the release of lachrymator compounds triggering the lacrimal glands to become irritated; we have all at some point found ourselves crying while chopping onions.
  • Heartburn – There are many theories as to why onions are more likely to cause heartburn for some, from their slower digestion, to irritating the esophagus, but it is yet to be tested.
  • Anticoagulant

IBS, Crohns and Coeliac

The group of people who this will be most significant for, is those with inflammatory diseases that affect the digestive system such as, IBS (irritable bowl syndrome), Crohns and Coeliac. As digestive diseases are very personal, learning the ability to sit, listen and observe, the signals of the body is essential to learning how to manage and heal from it. What affects one person will not necessarily affect you in the same way. Although you can gain guidance from sources such as Restorative Wellbeing, your body will be your best friend in this journey.

Those with chronic digestive problems often find a Low-FODMAP diet is a great starting point to discovering what foods suit their bodies best. Low-FODMAP is a three stage diet, starting with the elimination of FODMAP foods. This usually lasts 3-6 weeks. The second stage involves a slow steady process of reintroducing foods and noticing any that tigger symptoms, to find what triggers you. The final stage is adapting to your own personalised diet that you will have discovered through the introduction phase.

Many people who have gone through the Low-FODMAP process have found that onions have to be eliminated from their diet. However there are ways to avoid the causes of digestive problems from onions while still enjoying some of their benefits and flavour.

Low-FODMAP alternatives

  • Infused oils. Captureing the flavour of onions without the FODMAP properties of the onion being digested.
  • Spring onions/scallions/green onions tops. Just the green tops are Low-FODMAP
  • Chives. Part of the allium family, giving a subtle onion flavour when used as a garnish on dishes.
  • Leek tops. the same as with sping onions, stick to the greens and you will avoid the high FODMAP properties. A more subtle flavour than other alliums, but should help add nutrition and depth to your meals.
  • Asafoetida powder. Also known as hing, a traditional India seasoning that has a subtle onion flavour. (avoid if your are trying to conceive)

Low-FODMAP Recipes.


In short, if you are free from digestive issues, allergens or prone to heartburn, onions should definitely be a go to in your diet. The whole allium family of foods are abundant in health benefits to support your overall health. If you do find that onions prove to affect your health negatively, don’t overlook alternatives, that can still provide flavour and nutritions benefits to your meals.

Onion Recipes

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Please be aware all information in this blog is based on my own personal experience and research, and I am not a medical professional. If you are needing advice about a medical condition, please seek advice from a medical professional.

Published by Restorative Wellbeing

Fit mama focused on helping people make the most out of their workout and recovery.

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