Onions belong to the class of vegetables called Allium, the same class like garlic and chives. They are roundish with one pointed end and colour varies from red through yellow to white. Its origin is modern day Iran though onion is said to have been in use in China by 5000 B.C. Onion is said to have been brought to the New World by pilgrims.
Onions contain water, carbohydrates (including fibres and sugar), minerals (potassium, phosphorus, magnesium, calcium, and small amounts of iron, sodium and zinc), vitamins (vitamins C,and folates). They are said to also contain high levels of anti-oxidants in the form of Flavonoids and Quercetin, the latter is said to give the colour to onions.
They also contain sulphur-based gas which comes out when cut, this mixes with our eye tears to form sulphuric acid which irritates the eyes to produce more tears in order to dilute the acid. You can reduce this irritation by chilling the onions in a fridge before cutting or turn your eyes while cutting it.
The biggest producers of onion in the world include China, Pakistan, India, United States of America and Turkey.
1. Promote the health of the heart
High intake of soluble fibre reduces absorption of cholesterol and bile acid (which are also rich in cholesterol) from the small intestines, thereby reducing blood cholesterol level. When soluble fibres are broken down by bacteria in the intestines, some fatty acids released are said to reduce the production of cholesterol by the liver. By lowering blood cholesterol, fibres help to reduce the risk of heart disease.
Onions also contain a lot of magnesium, a mineral. This mineral helps to regulate your blood pressure by various means. A lot of studies have shown the good relationship between blood pressure and magnesium intake. When magnesium is low in the body, the heart fails to work well.
Onions are very rich in potassium which helps to prevent irregular heart beat and to reduce risk of stroke.
Onions have no fat, no cholesterol, both are harmful to the heart.
2. Slow aging
Onions are high in important antioxidants such as vitamin C , flavonoids and quercetins. These vitamins and minerals work to fend off cell damage from free-radicals. Consequently, onions may help to slow aging and age related diseases such as atherosclerosis and arthritis.
3. Fight against cancer
Onions are rich in fibres; many studies in the last three decades have shown a link between increased fibre in-take and a decrease in colon cancer. This could be due to the fibre itself or the nutrients that are usually in fibre-rich foods such as vitamins, minerals, phytochemicals and essential fatty acid. There are many fibre supplements in the market but it is not advisable that they be relied on solely for fibres owing to the reason stated above.
Daily consumption of onions is highly recommended.
4. Improve immunity
Onions contain Vitamin C which is required for the promotion of cell integrity in our body. Vitamin C is also an antioxidant which fights against free radicals that damage our cells. It is therefore said to increase our resistance to diseases.
5. Strengthen our bones
Onions contain a lot of phosphorus and calcium; both minerals are found mainly in the bones and teeth of our body. We must consume enough of them daily to ensure strong bones, proper growth and good teeth development. We will also avoid stiff joint and bone pain.
6. Prevents constipation
Onions as said earlier are rich in fibre which adds bulk to stool, making bowel movement easier. Insoluble fibre does this better. When plenty of fibre is consumed, the stool is large and soft, this stimulates the muscles of the intestines to contract, pushing out the stool (faeces) without the individual straining himself.