Onion, a world-class superfood, is versatile in various cuisines and offers valuable health benefits. It can help with weight loss, lower blood sugar, and prevent cancer and dementia.
Onions are an excellent source of nutrients such as folate, calcium, iron, dietary fiber, vitamin B6, vitamin C and potassium. In addition, they are low in calories and contain no fat or cholesterol.
Onions contain natural chemical compounds, such as organosulfur compounds, and flavonoids like quercetin, which can help fight disease and promote health.
What are the health benefits of onions?
1. Weight loss
In a clinical trial, 70 overweight participants were randomly divided into two groups. They received either a placebo or a steamed onion supplement before each meal for 12 weeks. The results showed that taking the steamed onion supplement reduced total body fat, especially abdominal visceral fat.
A study of 72 overweight and obese Korean subjects found that those who consumed quercetin-rich onion peel extract had significant reductions in body weight and body fat percentage, indicating that the onion peel extract has a potential anti-obesity effect.
2. Lower Blood Pressure and Improve Cardiovascular Health
Onion extract can regulate cholesterol, improve antioxidant capacity and suppress inflammatory markers, thereby mitigating the incidence of cardiovascular disease. In one study, researchers found that onion had better cardio-protective effects than red wine.
In a study of 70 overweight to obese subjects with prehypertension and stage I hypertension, researchers found that quercetin extracted from onion skin may lower blood pressure.
3. Reduced risk of Alzheimer’s disease and depression
The quercetin in onions may combat oxidative stress associated with neurodegenerative disorders such as Alzheimer’s disease, according to a study on the neuropotential role of quercetin.
Scientists have found that onions can alleviate stress-induced anxiety and depression in mice and improve their memory function.
4. Anticancer Effects
Onion extract exhibits anti-proliferative and anti-migratory effects on human adenocarcinoma cells (Caco-2), indicating that it may be an effective cancer therapy.
Researchers in Japan have found that a natural compound called onionin A (ONA) isolated from onions can inhibit the progression of ovarian cancer by suppressing protumor macrophage function and reducing cancer cell proliferation.
5. Prevention of osteoporosis
An analysis of national health data found that women who ate onions daily had 5% higher overall bone density than those who ate onions once a month or less.
6. Improved eye health
Using fresh red onion juice as eye drops in an animal experiment, researchers found that onion had an inhibitory effect on the growth of normal bacterial flora on the surfaces of the conjunctiva and eyelids.
In a separate animal experiment, researchers instilled fresh onion juice into the eyes of rats and found that onion juice can effectively prevent the formation of selenite-induced cataracts.
7. Increased hair growth
In a clinical trial, 38 patients with alopecia were treated with topical raw onion juice, which researchers found could promote hair regrowth and serve as an effective topical treatment for patchy alopecia.
8. Improved sleep quality
In a study of 30 healthy men and women who were dissatisfied with the quality of their sleep, subjects were given onion extract tablets containing concentrated cysteine sulfoxide; results have shown that these tablets can improve sleep quality and promote a smooth transition to sleep.
9. Boosted Immune System
A study found that the phenolic extract of onion bulbs could induce the proliferation of human immune cells, particularly the growth of CD16+ natural killer cells, which have anti-tumor and anti-infective effects.
10. Protected Liver
An animal study confirmed that regular consumption of onions could prevent non-alcoholic fatty liver disease, even in the presence of other risk factors (such as high cholesterol, obesity and high energy, fat and protein intake). sugar).
11. Lower blood sugar levels
According to the results of a clinical trial, the consumption of fresh yellow onions can effectively improve hyperglycemia and insulin resistance in breast cancer patients during chemotherapy.
12. A healthier respiratory system
A study showed that onions have a preventive effect on lung inflammation and can reduce tracheal reactivity in animals with asthma.
13. Protected reproductive system
An animal study found that onions can improve and protect testicular function and architecture from paraquat-induced oxidative damage.
A separate animal study found that oral administration of onion juice can improve sperm quality and fertility after testicular torsion or detorsion.
14. Reduced inflammation
A review of the anti-inflammatory effects of onion found that onion bulb extract could reduce the severity of colitis in mice by modulating the expression and activity of signaling pathways and various pro molecules. -inflammatories involved in the inflammatory response.
The results of a separate animal study showed that onions have a protective effect on gastric ulcers induced by ethanol and acid secretion. However, cooked onions show lower efficiency than raw onions.
15. Skin improvement
A study found that aqueous extracts of onions can inhibit the growth of fungi, such as Candida, Malassezia, and dermatophytes, in a dose-dependent manner.
Topical application of a 12% onion extract gel to cesarean section scars in Asian women can improve scar height and scar symptoms with no observed side effects, according to research.
How to Maximize the Potential Benefits of Onions
1. Don’t discard the outermost layer of the onion
Many people tend to discard the outer onion layers, but these may offer more benefits than the inner layers.
In a study published in the Journal of Food Science and Technology, onion bulbs were manually separated into three layers: outer, middle, and inner. The analysis showed that the outermost layers contained a higher concentration of antioxidant compounds than the middle and inner layers.
2. Use onion peel to make tea
The dry skin of the outer layers of onions is often discarded, but in some ways it offers far greater benefits than the flesh.
In a study published in the Journal of Functional Foods, the antioxidant activity of the phenolic constituents of the skin and flesh of onions of different colors (pearl, red, yellow and white) was measured. The results showed that the amount of phenolic content extracted from the onion skin was approximately six times that of the flesh. The extract from the edible part of the onion showed the lowest activity among all antioxidant tests performed.
Dr. Kim So-hyung, a Korean doctor, mentioned on his YouTube channel that the amount of quercetin in onion skin is significantly higher than in the flesh. Quercetin is a powerful antioxidant that can lower bad cholesterol, prevent damage to blood vessels, and help prevent hypertension, cardiovascular disease, diabetes, and obesity.
She recommends making tea with onion peel to maximize the health benefits of onions.
Onion skin tea recipe:
1. Dry and collect the onion skins after rinsing them with clean water (you can also add a few drops of vinegar).
2. Add about 10 grams of onion skins to 1 liter of water and start boiling.
3. After reaching the boiling point, cook for about 20-30 minutes.
Onion skin tea can be consumed anytime as a substitute for water. If you prefer a sweeter taste, add jujube or brown sugar to the ginger.
Precautions for Consuming Onions
Tina Yu, a nutritionist from Taiwan, mentioned on her Facebook page that there are a few things to keep in mind when consuming onions:
1. To avoid bloating and gas, onions should not be eaten in excess.
2. People with a humid-heat constitution should be careful when eating onions. This type of constitution is usually characterized by a preference for fresh foods, a dry mouth and tongue, a tendency to acne and constipation, reduced urine production with a yellow color, irritability and a tendency to inflammation.
3. People with itchy skin, eye disease, or inflammation of the lungs or stomach should consume onions in moderation.
4. Onions should be avoided in case of fever.
