What gives onions their smell

In this brief guide, we are going to answer the question “What gives onions their smell?” With an in-depth analysis of the nutritional value and health benefits of the onions. Moreover, we are going to discuss the downsides, storage and shelf life of the onions.

What gives onions their smell?

The distinctive smell of the onions is because of the presence of sulphur compounds in the onions.

When onions grow, they also absorb the sulphur from the soil and when these onions are cut these compounds are released into the air.

These sulphur compounds are volatile and give onions a distinctive smell.

Sulphur compounds present in the onions are also the reason behind the action of onions to make you cry while cutting them.

What is the nutritional value of onions?

The nutritional value for 3.5 ounces or the 100 grams of the onions is as follows;

  • Calories: 40
  • Water: 89%
  • Protein: 1.1 grams
  • Carbs: 9.3 grams
  • Sugar: 4.2 grams
  • Fibre: 1.7 grams
  • Fat: 0.1 grams

What are the health benefits of onions?

There are several health benefits of onions. Some of the benefits of the onions are as follows;

  • Onions help in regulating the sugar level in the blood and protect you from diabetes type 2 disease.
  • Osteoporosis is becoming a common disease, especially among women. Research has shown that the intake of selected fruits, herbs and vegetables such as onion can protect you from it.
  • Studies have also indicated that the regular consumption of the onions can also protect you from several types of the onions.

What are the potential downsides of the onions?

The use of onion can cause you bad breath and produce an unpleasant body odour.

There are several potential downsides of the onions too.  Some of them are as follows;

  • Raw onions can cause allergies in you whose symptoms include digestive disruption, such as upset stomach, heartburn, and gas.
  • Onions are also used to contain FODMAPs in them which are the carbs and the fibres to which many people are intolerant. That’s why you may suffer from bloating, diarrhoea etc.
  • Cutting onions can also result in irritation in the eyes and mouth or can make you cry.
  • Onions are healthy for humans, but they can be dangerous for various pets such as dogs,  cats and horses etc.
  • That’s why you shouldn’t give the onions to your pets.

Here are the precautionary measures that you should take while using onions.

How can you properly store the onions?

Proper storage of the onions is required to protect the onions from getting spoiled.

That’s why you should always keep them in the right place.  To store the onions well,  follow the instructions given below;

  • Always store the onions in a cold,  dry and well-ventilated place.
  • The temperature of the surrounding area where onions have been stored should be 45_55°F.
  • Avoid wrapping onions in any plastic wrap as it creates a hindrance in the path of the air to move through the onions.
  • Make sure to store the onions separately from the other things that release moisture such as potatoes.
  • You can store the cut onions in the fridge by putting them in a plastic wrap or airtight container.
  • You should also keep the onions away from the wall by almost a foot so that air can pass through them.

What is the shelf life of the onions?

The shelf of the onions depends on the way they have been stored.

If they are properly stored,  they have a longer shelf life just like garlic.

The shelf life of the onions is as follows;

  • The whole onion has a shelf life of 3 months in the pantry.
  • However,  once you cut the onions they can last for only 3_7 days in the fridge.

You should keep checking the onions every week and remove those which one bad to protect the rest of the onions from spoilage.

What are the signs of onions?

Onions can go bad. That’s why before using them you must check them.

You can easily get to know that your onions have been spoiled by noticing the few signs using your senses.

Some of the signs of the bad onions include the following;

  • Onions with the brown or black spots 
  • Dark patches on the skin of the onions
  • Discolouration
  • Foul smell


In this brief guide, we answered the question “What gives onions their smell?” With an in-depth analysis of the nutritional value and health benefits of the onions. Moreover, we discussed the downsides,  storage and shelf life of the onions.




Hi, I am Charlotte, I love cooking and in my previous life, I was a chef. I bring some of my experience to the recipes on this hub and answer your food questions.