Onions are vegetables that grow underground into tubers whose scientific name is Allium cepa .
They are also known as ordinary onions or onions, grown all over the world, and have relatives with onions, garlic , green onions, shallots and leeks.
Onions can bring many health benefits, mostly due to the high content of antioxidants and sulfur-containing compounds.
They have antioxidant and anti-inflammatory effects, and are believed to reduce the risk of cancer, hypoglycemia and improve bone health.
Onions are often used as a flavoring or side dish, and are a staple in Indian cuisine.
There are countless ways to enjoy onions. They can be baked, boiled, baked, fried, dried, sauce, rolled or mixed onion salad.
Onions look like this:
Onions have various sizes, shapes and colors, but the most popular types are white, yellow and red.
The onions of onions are also varied from sweet and mild to spicy, depending on the type of onion and season in the year.
We can also eat onions before the onions are large enough. They are called onions, spring onions or summer onions.
Fresh onions contain very little calories , only 40 calories per 100 grams (3.5 oz).
In terms of fresh weight, onions contain 89% water, 9% starch and 1.7% fiber, in very small amounts the protein and fat.
The table below contains information on all the main nutrients in onions .
|Vitamin B1 (Thiamine)
|Vitamin B2 (Riboflavin)
|Vitamin B3 (Niacin)
|Vitamin B5 (Acid panthothenic)
|Vitamin B6 (Pyridoxine)
Carbohydrates accounting for about 9-10% in both onions and onions.
They consist mainly of simple sugars like glucose, fructose and sucrose, as well as fiber.
One part 100 grams (3.5 oz) of onion contains 9.3 grams of carbs, and 1.7 grams of fiber, so the total digestible carb content is 7.6 grams.
Onions are a good source of fiber, accounting for 0.9-2.6% of fresh weight, depending on the type of onions.
They are rich in healthy soluble fiber called fructan. In practice, onion is one of the main fructan sources .
Fructan is also called prebiotic fiber. In other words, beneficial bacteria in the gut can consume them to generate energy.
This process leads to the formation of short fatty acids, like butyrate, which can improve the health of the large intestine, reduce inflammation and reduce the risk of colon cancer .
However, fructan is also known as FODMAP (fermented oligo-, di-, monosaccharide and polyol), which some people cannot digest.
FODMAP can cause indigestion symptoms in sensitive people, such as those with irritable bowel syndrome (IBS) .
Conclude: Onions mainly contain water, carb and fiber. The main fiber in onions is fructan, which can feed bacteria in the gut, but they can also cause digestive problems in some people.
Vitamins and minerals
Onions contain an abundance of vitamins and minerals.
The main types are listed below:
- Vitamin C: An antioxidant needed for immune function and skin and hair maintenance .
- Folate (B9): Water-soluble B vitamins are essential for cell growth and metabolism, and are especially important for pregnant women .
- Vitamin B6: Found in most foods, this vitamin is associated with erythrocyte formation.
- Potassium: This essential mineral can lower blood pressure, and is very important for cardiovascular health .
Conclude: Onions contain vitamin C, folate, vitamin B6 and potassium in moderate amounts.
Other plant compounds
Onions provide health benefits thanks to antioxidants and sulfur-containing compounds .
Onions are also one of the major sources of flavonoids in the diet in many countries, namely a beneficial compound called quercetin .
The most abundant plant compounds in onions are listed below:
- Anthocyanin: Only in red or purple onions, anthocyanin is a powerful antioxidant and is the pigment that helps onions red.
- Quercetin: Antioxidant flavonoid can lower blood pressure and improve heart health .
- Sulfur compounds: Mainly sulfide and polysulfide, may have anti-cancer effects .
- Thiosulfinate: Sulfur-containing compounds can inhibit the growth of harmful microorganisms and prevent the formation of blood clots .
Red and yellow onions are richer in antioxidants than others. In fact, onion can contain more than 11 times more antioxidants than white onions .
Cooking onions can significantly reduce some antioxidants .
Conclude: Onions contain plant compounds and antioxidants, especially compounds containing quercetin and sulfur. Color onions (yellow and red) contain more antioxidants than white onions.
Health benefits of onions
Onions have been shown to have strong antioxidant properties, reduce inflammation and prevent the growth of harmful microorganisms .
Effect against bacteria
There are many microorganisms in our environment as well as inside our bodies. Some of them can be harmful.
Onions and onion oils can prevent the growth of harmful microorganisms, such as bacteria and yeast .
Adjust blood sugar
Diabetes is a common disease, characterized by high blood sugar levels.
Animal studies show that onions can reduce blood sugar .
This has also been shown in humans. A study in diabetics found that eating 100 grams of onion per day significantly reduced blood sugar .
Fresh onions can be beneficial in controlling type 1 and 2 diabetes, but we need to study this aspect more .
Osteoporosis ("spongy" bone) is a common health problem, especially in postmenopausal women. A healthy diet is one of the main precautions .
Animal studies have shown that onions have a protective effect against bone degradation and may even increase bone mass
A very large observational study in women over 50 years of age showed that frequent consumption of tubers was associated with increased bone density .
A new controlled trial also showed that select fruits, vegetables and herbs, including onions, can reduce bone loss in postmenopausal women .
Prevention of cancer
Cancer is a common disease, characterized by uncontrolled growth of cells in the body. This is one of the leading causes of death in the world.
Observational studies have shown an association between increased onion consumption and reduced risk of cancer, such as stomach cancer, breast, colon and prostate cancer .
Conclude: Onions have antioxidant and anti-inflammatory effects. They can help fight infections, lower blood sugar, improve bone health and reduce the risk of certain types of cancer.
Side effects and personal concerns
Eating onions can lead to bad breath and cause body odor.
There are also some other onions that can make them unsuitable for some people.
Intolerance and allergic reaction
Allergy is relatively rare, but the phenomenon of intolerance to fresh onions is quite common.
Symptoms of intolerance include gastrointestinal symptoms, such as abdominal pain, heartburn and farting .
Some people may experience an allergic reaction when they touch onions, regardless of whether they are allergic to onions .
Contains FODMAP, short-chain carbohydrates that many people cannot digest .
They can cause unpleasant gastrointestinal symptoms such as bloating, farting, cramping and diarrhea .
People with irritable bowel syndrome (IBS) are often intolerant of FODMAP, and may want to avoid eating onions.
Irritating to eyes and mouth
The most common problem in preparing and cutting onions is eye irritation and watery eyes.
This happens when we cut onions. When cut, the cells will release a gas called a lachrymatory (LF) .
This gas activates the neurons in the eye, causing a stinging sensation, after which tears are created to wash away the gas causing irritation.
Keeping onion roots while cutting can reduce irritation, root onions have higher concentrations than onions.
Cutting onions in water or under running water can also prevent this gas from dissolving into the air.
The factors that cause tearing (LF) are also the cause of hot feeling in the mouth when eating onions .
It is possible to cook onions to reduce or eliminate this hot feeling.
Dangerous for pets
While onions are a healthy ingredient in the human diet, they can make some animals, including dogs, cats, horses and monkeys die .
The main culprits are compounds called sulfoxyde and sulfide, which can cause the so-called disease .
Heinz anemia is characterized by lesions in red blood cells, leading to anemia .
Make sure your pet doesn't eat onions, and if you keep pets in your home, keep anything that is out of reach.
Conclude: Onions can cause adverse gastrointestinal effects in some people, and fresh onions can irritate the eyes and mouth. Onions can be toxic to some animals.
Like many other foods, onions also have "good" and "bad" aspects.
They have many antioxidants and sulfur-containing compounds, some of which may have beneficial health effects.
Although more research is needed to confirm, onion is associated with improved bone health, reduced blood sugar and reduced risk of cancer.
On the other hand, they can cause problems in some people, especially digestive problems in people who do not tolerate FODMAP.
As said, onions are usually consumed in small amounts. Their main purpose is to provide flavor, not nutrition.
For those who can tolerate (and enjoy) onions, they can be a valuable component of a healthy diet.