While onions offer many health benefits, consuming an excess amount can lead to gastrointestinal distress, such as irritable bowel syndrome and acid reflux.
Although onions are quite safe to consume, rarely they may harm your health if you have any underlying health conditions or when you consume them in excess.
- One of the most popular drawbacks of eating onions is their tendency to give you bad breath and body odor.
- Although rare, people may develop allergic reactions to onions, particularly onion seeds, in which symptoms present as itching, watering of the eyes, and skin rashes on coming in contact with onion or onion extracts.
- Onions may cause symptoms of gastrointestinal upset, such as heartburn, bloating, abdominal discomfort, nausea, and vomiting, in susceptible individuals, which may aggravate symptoms of irritable bowel syndrome in affected individuals. These symptoms are relatively more common when eating onions raw rather than cooked. Raw onions may especially make you more flatulent.
- Onions are generally recognized as safe when consumed in moderation during pregnancy. However, consuming onions in excess or as supplements must be avoided by pregnant and breastfeeding women due to a lack of data on its safety.
- Some studies suggest that onions may slow blood clotting. Hence, consuming onions as extracts or supplements must be avoided if you have bleeding disorders. Although enough scientific evidence is not available about the interaction between onion supplements and antiplatelet drugs, avoid taking onion supplements if you take antiplatelet medications or other blood thinners without getting your doctor’s approval.
- Certain animal studies and clinical trials have demonstrated that onions can lower blood sugar levels. Thus, monitor your blood sugar levels regularly if you take onion supplements and anti-diabetes medications.
- Because onions have been associated with a lower blood glucose level and bleeding tendency, it is better to avoid such supplements before surgery. You must inform your surgeon if you take any drugs or supplements, including onion supplements, before surgery.
What are the health benefits of onions?
The onion, also known as the bulb onion, belongs to the lily family (Liliaceae) that also includes garlic, chives, and leeks, which are popular ingredients across various cuisines. They are low in calories and fats and high in fiber and antioxidants.
A medium-sized onion (about 2.5 inches diameter, 110 grams in weight) contains the following:
| Nutrient | Nutrient Amount |
|---|---|
| Calories | 44 kcal |
| Water | 98 g |
| Fiber | 1.87 g |
| Protein | 1.21 g |
| Fats | 0.11 g |
| Calcium | 25.3 g |
| Iron | 0.23 g |
| Magnesium | 11 mg |
| Potassium | 161 mg |
| Sodium | 4.4 mg |
| Phosphorous | 31.9 mg |
| Vitamin C | 8.14 mg |
| Folate | 20.9 mcg |
| Vitamin A | 2.2 si |
Onions contain B vitamins, vitamin E, zinc, sulfur, copper, lutein, and several other antioxidants that promote health. Consuming onions as a part of a balanced diet may give various health benefits including:
- Healthy immunity
- Weight management
- Controlled blood sugar
- Reduced inflammation
- May reduce risk of certain cancers, such as gastrointestinal and endometrial cancers
- Relief from arthritis
- Improved blood lipid levels
- Improved cardiovascular health
- Improved bone health
- Reduced skin scarring and irritation
- Healthy hair
Depending on the onion plant or the onion growing season, onions can come in many different forms that offer various tastes and health benefits. The different types of onions include:
- Red onions
- Yellow onions
- White onions
- Green onions
- Spring onions
- Shallots
- Scallions
Why do your eyes tear up on cutting onions?
Onions contain various sulfur compounds, including propanethial-S-oxide, which are volatile and escape as vapors when cutting onions. These sulfur-containing vapors form a dilute form of acid that causes eye irritation and tearing (lacrimation).
To minimize the irritation, you may hold onions in water for some time and then cut them using a sharp knife. Alternatively, keep the onions in the refrigerator for about 30 minutes before cutting. Avoid cutting the root part of the onion as it contains most of the sulfur compounds that make your eyes well up with tears.
References
Drugs.com. Onion. https://www.drugs.com/npp/onion.html
eMedicinehealth. Onion. https://www.emedicinehealth.com/onion/vitamins-supplements.htm
Food Data Central. Onions, raw. https://fdc.nal.usda.gov/fdc-app.html#/food-details/170000/nutrients
