Mr b, a dietician and Head , Department of Dietetics at the University College Hospital (UCH), Ibadan in Oyo state , has said that the consumption of onions can lower the risks of several types of cancer.
Ajobo told the News Agency of Nigeria (NAN) that, "Onions are part of the allium family of vegetables and herbs, which also includes chives, garlic, scallions and leeks.
"Allium vegetables have been cultivated for centuries for not only their characteristics, pungent flavours but also for their medicinal properties,’’ he said.
The dietician also recommended consumption of onions because of its other many health benefits
"Allium vegetables have been studied extensively in relation to cancer, especially stomach and colorectal cancers.
"Their beneficial and preventive effects are likely due in part to their rich organosulfur compounds.
"Although the exact mechanism by which these compounds inhibit cancer is unknown, possible hypothesis include the inhibition of tumor growth and mutagenesis and prevention of free radicals.
He added that several studies have proven that onion consumption helps to lower the risk of stomach cancer, colorectal cancer, colon and prostrate cancer, he said.
Ajobo said that the health benefits of consuming onions besides lowering risk of several cancers also included improving mood and maintaining the health of skins and hairs.
"Onions are a nutrient-dense food, meaning that while they are low in calories; they are high in beneficial nutrients like vitamins, minerals and antioxidants.
"One cup of chopped onion contains approximate 64 calories, 15 grams of carbohydrates, no fat and cholesterol.
"It also contains three grammes of fibre, seven grammes of sugar, two grammess of protein and 10 per cent or more of daily value for Vitamin C, Vitamin B-6 and manganese.
"Onions also contain small amount of calcium, iron, folate, magnesium, phosphorus and potassium and the antioxidants quercetin and sulphur," he said.
The dietician, however, said that consuming a diet of mostly onion has its health risks.
"It is best to eat a diet with a variety than to concentrate on individual foods as key to good health," he said.
Ajobo said that onions vary in sizes, shapes, colours and flavour adding that the commonest types are red, yellow and white onions.
He said that onion flavours could also vary from sweet and juicy with a mild flavour to a sharp, spicy and pungent.
This often depends on the season in which they are grown and consumed, he said.
He said an estimated 105 billion pounds of onions are harvested each year worldwide with a quarter of the figure grown in Africa.