Sorry, you're wrong.

FACT: "Trying to stay fit and eating healthily is the best natural protection against colds and flu."

Although it is difficult to avoid exposure to viruses that cause colds and flu, strengthening your body's defences will help to fight off invading viruses before they take hold. Stress, cold weather, lack of sleep and poor nutrition can all make you physically low and increase the likelihood of you becoming infected. Vitamin C and zinc, as a supplement to a healthy diet and lifestyle, are thought to help maintain your body's defences against infection. (See "Feed a cold, starve a fever").