Garlic and onions contain compounds called allyl sulphides which provide them with their distinctive, though not always pleasant smell.
The main chemical that has been isolated in garlic is alliin. When garlic is crushed, alliin combines with the enzyme allinase to produce allicin. It is thought to be responsible for helping reduce the risk of cancer and heart disease. It is believed that onions behave in a similar manner to garlic, although to a lesser degree.
To obtain maximum benefit from the allium group of vegetables, try to follow these practical tips:
Eeat two to five cloves of garlic a week. Ideally garlic should be eaten every day together with at least one member of the onion family.
You can eat garlic and onions on a daily basis by adding them to your food as part of the seasoning and flavouring with the knowledge that only 10 per cent of their effectiveness is lost in cooking.
You can take garlic as a supplement. Use garlic tablets, as there is little benefit in taking garlic oil which does not contain allicin.