Garlic and onions complement each other in more ways than one. These two kitchen staples are so frequently used together that many recipes would not be the same without their joined flavors. Their immune-enhancing effects also make garlic and onions a potentially formidable force against common cold and flu viruses.
Natural Killer Cells
Use garlic and onions liberally to avoid catching colds and flu, says author Jordan Rubin in "The Great Physician's RX for Colds and Flu." Garlic improves the activity of natural killer cells, a type of immune cell that is specifically designed for cold and flu viruses and cancer cells. Garlic and onions contain compounds that are similar ingredients in over-the-counter cold and flu remedies. These compounds have the ability to dry out congested nasal passages and prevent mucous accumulation. Add horseradish, a plant with similar medicinal qualities to garlic and onions, for a triple threat to any cold or flu virus that comes your way.
Onions contain the same compound, allicin, that gives garlic its famous infection-fighting qualities, according to pharmacist J. Albert Hermle, author of the book "Finally!!! Stop Having Colds & Flu." Allicin has the ability to slow and kill a variety of viruses and bacteria. Hermle recommends eating fresh raw white onion within 4 hours of the first signs of a cold or flu, as it is more effective at this early stage than once an infection has taken hold and spread. Using raw white onion may greatly reduce your need for antibiotics.
Make a soup with six onions, an entire bulb of garlic, about an inch of grated fresh ginger and cayenne pepper to chase away colds and flu, advises health journalist Hazel Courteney, author of the book "500 Health Tips - An A-A of Alternative Health Hints to Help More Than 200 conditions." Garlic and onions bring antiseptic qualities and cayenne pepper boosts the effectiveness of the other herbs.
Garlic may be highly effective as a preventive for the common cold, according to a study conducted by Seekers Centre for Integrative Medicine, Ottawa, Ontario. The review of previously published literature cited a small clinical trial on the effects of garlic. Other notable natural cold preventives mentioned in the study include vitamin C and ginseng. For treatment, rely on echinacea and zinc. Researchers called for further studies on garlic's effectiveness. The study was published in the January 2011 issue of the journal "Canadian Family Physician."