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.
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 |
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:
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.
Because they are so low in potassium, onions are considered safe to eat for people with kidney problems.
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).
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:
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:
You can also eat certain dairy products known for their potassium richness. Such dairy products include:
There are fish that are a good source of potassium, including:
If you do not like green vegetables, you can eat beans or legumes known for being high in potassium, including:
Some other common foods that are rich in potassium include:
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:
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.
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).
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).
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).
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).
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.
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:
When selecting onions, look for onions that are firm and have no scent before peeling.
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:
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).
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.
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).
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:
. 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.
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.
Yes. There are many advantages to eating raw onions. However, you may also feel a burning sensation on your tongue.
Onions are considered low potassium vegetables, so it is highly unlikely to consume excessive potassium from onions alone.
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