cebolla

What is cebolla?

Cebolla is the everyday onion, Allium cepa. It is a food first and a home remedy second. In Latin American kitchens it is best known as a cough syrup, made from sliced onion with honey or sugar.

Home use also covers colds, blocked noses, sore throats, earache, bites and minor skin trouble. Onion slices are also laid on the chest or left in a sick room. These habits are old and very widespread.

Traditional use tells you that a plant was valued. It does not prove that it works, and it is not proof that it is safe.

Here is the plain verdict. Onion is a safe, useful food for most people. Human evidence for the remedy claims is thin, short and mixed.

How does cebolla work?

No one has shown how onion would treat a cough in people. Most of what is known comes from test tube and animal work.

Cutting an onion releases sulphur compounds. In lab tests these slow some bacteria and fungi. Whether that happens in your throat, your ear or on your skin is not established.

Onion is also rich in quercetin, a plant pigment. In cell studies quercetin calms signals linked to swelling and allergy. In people the picture is much less clear.

In small human trials, onion and onion peel extract lowered blood pressure and some blood fats a little. The effects were small and the trials were short.

Some onion sulphur compounds thin the blood slightly in lab work. Food amounts are not thought to matter for most people.

One effect is not in doubt. The gas from a cut onion stings your eyes and makes them water. That is a direct chemical effect, not a treatment.

What forms does cebolla come in?

Onion is used as food far more often than as a supplement.

- Raw bulb: slices, juice or grated pulp. - Cooked bulb: the normal kitchen form. - Onion and honey syrup: the classic home cough mix.

- Onion tea: simmered slices, sometimes with lime or honey. - Poultice: warm onion wrapped in cloth and laid on the chest or skin. - Onion skin tea: brewed from the dry outer peel.

- Capsules and tablets: onion or onion peel extract, often sold as quercetin. - Scar gels: pharmacy creams made with onion bulb extract.

Strength differs hugely between these forms. A kitchen syrup and a standard extract capsule are not the same thing.

There is also a homeopathic product called Allium cepa. It is sold for runny noses and watery eyes. It is so dilute that it is a different product from the herb, and the two should not be confused.

Where it comes from:

Onion came from Central Asia and spread through the Middle East and Europe. Spanish settlers brought it to the Americas in the 1500s. It entered local kitchens and local healing fast.

In Latin American homes, onion syrup was a standard answer to a child's night cough. Cooks layered sliced onion with sugar or honey and used the liquid that formed.

Other old household customs included these.

- Onion slices were laid on the chest or the soles of the feet during fevers. - A warm onion was held near a sore ear. - Cut onion was left in a sick room to "catch" the illness.

- Raw onion was rubbed on insect bites and bruises. - Onion water was used as a hair rinse. - Onion appeared in limpias and other cleansing rites.

Onion was always a food, so it was never a restricted or secret remedy. That is part of why it spread so far. None of these customs were tested in their own time.

What does cebolla help with?

• Cough and chest colds: This is the main Latin American use, as onion and honey syrup. There are no good human trials of onion syrup for cough. Honey alone does help night cough in children over one year, and that is tested. The onion part is unproven.
• Sore throat: Tradition used onion tea or syrup to soothe a raw throat. Any relief is likely from the warm, sweet liquid rather than the onion. No human trial has tested onion for sore throat.
• Blocked nose and hay fever symptoms: Cut onion was placed near the bed to open the nose. The sulphur gas does irritate the nose and eyes, which can make them run. That is irritation, not treatment. There is no human evidence that it shortens a cold or eases hay fever.
• Earache (home custom only): A warmed onion held near the ear was a common comfort measure. No trial supports it. Nothing should be put inside the ear canal. Ear pain with fever, discharge or hearing loss needs a doctor, not a kitchen remedy.
• Insect bites and minor skin irritation: Raw onion was rubbed on bites and bruises. In lab tests onion extracts slow some bacteria, but that has not been shown to help on skin. Onion juice can also sting and can cause a rash in sensitive people.
• Scars: Pharmacy gels with onion bulb extract have been tested in several small trials. Results are mixed. Some trials found slightly better scar colour or texture. Others found no gain over a plain moisturiser.
• Patchy hair loss: A small 2002 study put raw onion juice on patches of alopecia areata (sudden patchy hair loss). More people regrew hair than with tap water. The study was tiny and has not been confirmed by a large trial. Onion juice also smells strongly and can irritate the scalp.
• Blood pressure and blood fats: Reviews that pool small trials of onion or onion peel extract report small drops in blood pressure and in some blood fats. The trials were short and varied in quality. This is a possible modest food effect. It is not a treatment for high blood pressure (raised pressure in the arteries).
• Blood sugar: Animal work and a few small human studies suggest onion may lower blood sugar a little. The evidence is weak and not consistent. Do not change diabetes medicine on the strength of it. Talk to your doctor first.

Which foods are rich in cebolla?

1. White onion
2. Red onion
3. Yellow onion
4. Shallot
5. Spring onion
6. Leek
7. Garlic

Practical Tips:

Cebolla is itself a food, so there is no need for a supplement to get it. Red onions and the dry outer skin hold the most quercetin.

Related bulbs such as shallot, leek and garlic share many of the same sulphur compounds.

What are the side effects of cebolla?

• Onion breath and body odour
• Burping and heartburn
• Gas, bloating and loose stools
• Worse symptoms in IBS (irritable bowel syndrome)
• Stinging, watering eyes when chopping
• Skin rash or itching from handling or from a poultice
• Mouth or throat tingling in people allergic to onion
• Rare true allergy with swelling and wheezing

Good to know:

Most effects are mild and come from the gut. Gas, burping and onion breath are the common ones.

True onion allergy is rare but real. Swelling of the lips, tongue or face, or wheezing, is an emergency.

People who handle raw onion all day sometimes get itchy, cracked hands. That is contact irritation, not allergy in most cases.

How much cebolla should you take?

• Recommended daily: Onion is an ordinary food, so most people simply eat it in meals. No health agency has set a remedy dose. Labels on onion extract and quercetin capsules commonly carry 300 mg to 1000 mg a day. That is what the label says, not advice for you. A pharmacist or your doctor can say whether a concentrated supplement suits your case and your medicines.
• Best time of day: Timing does not matter much. The syrup is often used at bedtime, because night coughs bother people most. Raw onion late at night can trigger heartburn in some people.
• With or without food: Onion is normally eaten with meals. Raw onion on an empty stomach often causes burning and burping. Extract capsules are usually taken with food for the same reason.
• Time to effect: A warm syrup or tea may soothe a throat within minutes, and the comfort fades fast. That is warmth and sweetness as much as onion. In trials of onion extract, any change in blood pressure or blood fats took weeks. It may also do nothing at all.
• How long to take it: As a food, onion needs no time limit. Home remedy use is usually short, a few days around a cold. If a cough, earache or skin problem lasts beyond one to two weeks, it needs a proper check. More onion is not the answer.