First, you need to know what you're up against. In addition to the flu, the average adult suffers anywhere from one to three respiratory illnesses a year, nearly all of them caused by viruses and most of them occurring in the fall and winter. Winter also tends to bring out the kind of bad habits from overindulging at parties to letting exercise routines slide that make the body more susceptible to infection.
The reason we get colds in winter isn't directly linked to cold weather, of course. It's that we spend more time indoors with other people and their germs. If you really wanted to make sure you never suffered another cold, you would avoid all contact with other people as well as anything they had ever touched. And you would certainly abandon those ritual handshakes and cheek pecks. Why? Respiratory viruses, including those that cause flu, are highly contagious and can survive for hours on skin, furniture, doorknobs and the like.
If you're not ready to become a hermit or a germophobe, you can do what we doctors do before we meet a patient: lather up. "Good hand washing will do more to prevent the spread of illness and respiratory infections than anything else," says Dr. Carolyn C. Lopez, of the American Academy of Family Physicians. Although recent studies have found no difference in the effectiveness of alcohol-based gels, antibacterial soaps or plain soap and water, my vote still goes to the alcohol gels. They're much easier to carry around and, unlike antibacterials, they won't foster the development of resistant germs.
Some people swear by humidifiers, believing that they help prevent those little cracks in the dried-out lining of the nostrils that can let germs in. But if you use a humidifier, be sure to refill it daily with distilled water, as it can harbor bacteria. And you should be aware that too much humidity can make you more susceptible to viruses.
Winter family get-togethers and holiday parties can also be hazardous to your health. Try to stick to your regular sleep routine, and if you must drink alcohol, do so in moderation and follow it with plenty of water. Lack of sleep and dehydration both tend to suppress your body's natural abilities to fight off illness.
Of course, you could do everything right and still get sick. Prescription drugs like Tamiflu and Relenza can shorten flu infections by a day if you start taking them within 48 hours after symptoms appear. (Their greatest benefit may arise when others take them to keep from catching your flu.) There's some evidence that 1,000 mg of vitamin C may act like an antihistamine and lessen the severity of cold symptoms. Chicken soup is still a great way to get your liquids, but make sure it's clear, not creamy, or you could end up irritating your intestinal lining. If all else fails, just remember that spring is less than 20 weeks away.
Dr. Gupta is a neurosurgeon and a CNN medical correspondent