How Much Potassium is in Onions (Must Read)

According to the National Onion Association, the average consumption of onions per capita was over twenty pounds per person in 2018 (1).

Onions have been appreciated for their versatility in food and taste, being used for various dishes.

Are onions good for you?

Although many people consume onions daily, they might not be aware of some of the nutritional facts about onions. In this article, we will inform you about the amount of potassium in onions and should you be eating them.


Nutritional Facts About Onions

Onions, a vegetable of the Allium plant family along with garlic and leeks, are known for their pungent smell and versatile flavors. The table below informs about some of the nutrients found in a hundred grams of onions (2):

Nutrient Amount per 100 grams
Calories 40
Fat 0.1 g
Protein 1.1 g
Carbohydrates 4.2 g
Fiber 1.7 g
Sodium 4 mg
Potassium 146 mg
Magnesium 2% of Recommended Daily Intake
Calcium 2% of Recommended Daily Intake
Iron 1% of Recommended Daily Intake
Vitamin C 12% of Recommended Daily Intake
Vitamin B6 5% of Recommended Daily Intake


Plant Compounds in Onions

Onions are famous in the medical and herbal industry for their health benefits. According to a study, most of these benefits are accredited to the antioxidants and sulfur-containing plant compounds (3).

The four major plant compounds found in onions are:

  1. Anthocyanins: These are antioxidants responsible for the colors in red and purple onions.
  2. Quercetins are antioxidants known as flavonoids and help control blood pressure.
  3. Sulfur Compounds: Consist of sulfides that can reduce the risk of cancer.
  4. Thiosulfinates: Consist of sulfur-containing compounds that can protect against pathogens.


Potassium in Onions

Onions contain around 146 milligrams of potassium per 100-gram serving. This makes onion low-potassium vegetables. For a better understanding of the potassium in onions, below is the list of the different onion items and their potassium level per 100 grams.

  • Onion flakes: 1.622 milligrams
  • Spring onions: 276 milligrams
  • Cooked onions: 166 milligrams
  • Green onions: 159 milligrams
  • Frozen onions: 142 milligrams
  • Yellow onions: 133 milligrams
  • Sweet onions: 119 milligrams
  • Onion soup: 68 milligrams

Because they are so low in potassium, onions are considered safe to eat for people with kidney problems.


Role of Potassium in Body

Potassium is one of the essential minerals required by the body. Potassium helps the body in nerve function and maintaining osmoregulatory pressure in cells.

Potassium maintains the optimum fluid levels in intracellular spaces, while sodium is responsible for maintaining optimum fluid levels in extracellular spaces.

There are many health benefits of potassium. Research has shown that potassium is able to lower blood pressure.

Studies show that it can reduce the effects of salt sensitivity (4). It can also reduce the risk of stroke (by 27%) (5). Some studies have even shown that potassium can help patients with a high risk of osteoporosis, while some prove that it lowers the possibility of formation of kidney stones (6,7).

According to the World Health Organization, the required daily potassium intake should be thirty-five hundred milligrams per day (8). The National Institute of Health recommends a required daily intake of forty-seven hundred milligrams per day (9).


Food Rich in Potassium

Onions may not fulfill your required daily intake of potassium, but there are many other potassium-rich foods that you can take instead.

Potassium is found in fruits and vegetables, including:

  • Bananas
  • Oranges
  • Cantaloupe
  • Grapefruit
  • Spinach
  • Broccoli
  • Potatoes
  • Mushrooms
  • Cucumbers

If you do not like eating vegetables or fruits, you can choose to drink fresh juice from potassium-rich fruits. Some examples of potassium-rich juices are:

  • Orange juice
  • Tomato juice
  • Grapefruit juice

You can also eat certain dairy products known for their potassium richness. Such dairy products include:

  • Milk
  • Yogurt

There are fish that are a good source of potassium, including:

  • Tuna
  • Cod
  • Trout

If you do not like green vegetables, you can eat beans or legumes known for being high in potassium, including:

  • Lima beans
  • Kidney beans
  • Lentils
  • Soybeans

Some other common foods that are rich in potassium include:

  • Nuts
  • Dried fruits such as raisins and dates
  • Poultry and Meat
  • Brown rice
  • Cereal


Risks Associated With Potassium

Too much of something good is bad. The same goes for potassium. Excessive intake of potassium can prove dangerous. Research shows that in most cases, consuming more than forty-seven hundred milligrams of potassium per day does not benefit in any way (10).

Consuming too much potassium can adversely affect the kidney, as the kidney is the organ responsible for excreting excess potassium (11).

Studies show that overworking the kidney by consuming excessive potassium may cause kidney damage or even kidney failure (12).

Additionally, certain groups of people are advised to control their potassium intake. These groups include:

  • People who suffer from kidney diseases.
  • People who are taking blood pressure medication.
  • Old-age groups.


Health Benefits of Onions

Although onions are low in potassium, they are still considered healthy for you. This is because onions contain many other nutrients that can help the body. The different benefits of onions to your health are mentioned below.


Prevent Cancer

Research has shown that onions my be beneficial for the prevention of many types of cancers. A study showed that onions decreased the risk of esophageal cancer, colorectal cancer, breast cancer, ovarian cancer, prostate cancer, and renal cell cancer (cancer of the kidney) (13).

This could be because onions are high in antioxidants.

Antioxidants can neutralize oxidants in the body, which cause the creation of free radicals that harm the cell and cause cancer. A study showed that the sulfur-containing compound in onions could reduce tumor development and the spread of lung cancer (14).


Better Heart Health

The antioxidants and anti-inflammatory compounds, such as the flavonoid antioxidant, Quercetin, in onions can reduce cholesterol levels in the body and lower blood pressure, reducing the risk of cardiovascular diseases.

A study showed that women suffering from polycystic ovarian syndrome could reduce the about of LDL cholesterol (bad cholesterol) in eight weeks by consuming raw red onions (15).

Another study showed that anthocyanins in onions could reduce the risk of a heart attack in men by fourteen percent (16).


Control of Blood Sugar Levels

Certain compounds in onions, such as Quercetin and sulfur-containing compounds, possess anti-diabetic properties. In a study, Quercetin was shown to interact with pancreatic cells, small intestine, muscles, and liver to help blood sugar regulation (17).

Another study showed that patients suffering from type 2 diabetes lowered blood sugar levels in four eyes by consuming red onions (18).


Antimicrobial Effects

Thiosulfinates in onions has shown increased antibacterial effects. Onion extracts were shown to decrease the growth of pathogenic bacteria, Vibrio cholera, known to cause cholera (19).

A study showed that Quercetin, a substance high in onions, was able to inhibit the growth of Methicillin-resistant Staphylococcus aureus (MRSA), an antibiotic-resistant bacteria (20).


Increase Digestion

Onions are high in fiber and prebiotics, increasing the body’s digestive capabilities.

Onions contain acetate, propionate, and butyrate that act as prebiotics and have been shown to decrease inflammation and enhance digestion (21). Other prebiotics in onions, such as inulin and fructo-oligo-saccharides, have been shown to promote the growth of beneficial bacteria in the gut (22).

The fiber in onions helps in the peristalsis movement of the intestine and improves digestion.


How to Add Onions to Your Diet

Onions are found in every kitchen worldwide and are versatile vegetables used in various foods. There are many ways you can add onions to your diet. Here are some tips that you can follow:

  • Use raw onions in salads
  • Use caramelized onions in baked goods
  • Sautee onions with other vegetables to eat as a side dish
  • Use onions in omelets
  • Add onions to a burger
  • Use chopped onions in Mexican dishes
  • Make onion soup
  • Use onions in a salsa
  • Cook onions with meat or poultry
  • Pickle onions
  • Make onion dip

When selecting onions, look for onions that are firm and have no scent before peeling.


Risks associated with onions

Onions are a delicious and nutritious vegetable, but some risks are associated with onions for people who eat them. Milder risks include bad breath and body odor.

More severe risks are mentioned below:


Onion Allergy

An allergy to onions is rare but not unheard of. Research shows that people suffering from onion allergy experience digestive problems, heartburn, and gas (23). Onion allergy can either be at birth or induced later in life.

People suffering from onion allergies can react not just from eating them but also from touching them (24).


Digestive Problems

Onions contain fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) that sit inside the digestive tract and ferment, producing gas (25).

This can cause many digestive problems, including bloating, nausea, vomiting, and diarrhea.



The most common risk associated with onions is irritation in the eye and the mouth. Study shows that when cut, onions release the lachrymatory factor (LF) gas that can cause eye irritation and tear production (26).

LF gas is also responsible for mouth irritation, in which a person can feel a burning sensation on the tongue. This is often experienced when onions are eaten raw.


Not Safe for Pets

Onions can be deadly for many animals, including dogs and cats. Research shows that sulfoxides and sulfides in onions can cause Heinz body anemia disease in animals, decreasing the number of red blood cells in the body (27).


In Conclusion

While potassium in onions is low, they still have many nutrients that are beneficial for the body.

Onions are beneficial for health but also carry some risk factors you must be careful of.

If you are looking for a rich potassium diet, there are many other food options that you can include in your diet, but that does not mean you need to remove onions from your diet altogether.

Further reading:



1. Are Onions Healthy?

. Onions are high in fiber, antioxidants, vitamin C, iron, and other nutrients. Onions have many benefits, including better heart health, digestive aid, a stronger immune system, and reducing the risk of cancer.


2. How Can I Reduce Irritation Caused by Onions?

One way to reduce the irritation is by cutting off the roots, which contain the most LH gas irritating the eyes. Another method is to run the onions in cold water before cutting them. Cooking onions can eliminate the LH gas.


3. Can I Eat Onions Raw?

Yes. There are many advantages to eating raw onions. However, you may also feel a burning sensation on your tongue.


4. Can You Consume Too Much Potassium From Onions?

Onions are considered low potassium vegetables, so it is highly unlikely to consume excessive potassium from onions alone.