Knowhow team explain: Onions come in many varieties and three main colours — yellow, white and red. They are rich in nutrients including vitamins B and C, protein, calcium and iron.

It is not the strong odour of the onion that makes us cry, but the substances that the onion releases when we chop it. The vegetable contains some sulphur compounds which are released when chopped. Sulphur being an irritant to both our nose and eyes, makes tears flow out.

What actually happens when the sulphur compound comes in contact with the water in our eyes is this: it produces very dilute sulphuric acid. This acid then irritates the eyes. In response to this acid, our eyes automatically blink and produce tears, which wash the eye and flush out the acid.

An automatic reaction many people show is to rub their eyes with their hands, which often makes the situation worse, because our hands are covered with the sulphur compounds from cutting the onion, which we then rub directly into our eyes.

The only remedy for this problem is to boil the onion, not to slice it or cut it up, which is not very practical. Some people suggest putting the onion in the freezer for a few minutes because the cold decreases the speed of the chemical reaction. Another tip is to slice the area around the root of the onion last. Why? Because there are more sulphur compounds in the onion root.

British farmers have developed a new kind of onion, called Supasweet onion. It is said to be so mild that it can be eaten like an apple. Supasweet onions have been available in supermarkets around England since August 2003. The onion has a pale, thin skin, is easy to peel and quick to prepare. Supasweet onions are not genetically modified. Their secret is that they have been specially grown in low-sulphur soils!