Immunity Boosters for Cold and Flu Season

Honeysuckle and forsythia
Botanist Jim Duke swears by these two common plants, which have a long history in traditional Chinese medicine, as a way to ward off respiratory infections. A variety of lab studies show both contain substances that act against viruses.

Worth a try for: Preventing or treating both colds and flu.

How to do it: If you’re lucky enough to have honeysuckle or forsythia bushes in your yard, gather stems, berries, and bark, and use them to brew a tea (add lemon and sugar). If your garden’s bare, many Chinese and Japanese herbal formulas combine honeysuckle and forsythia. Cold Snap contains Japanese honeysuckle and forsythia, along with 20 other herbs.

Pelargonium sidoides
This herb has long been used in South African traditional medicine to treat coughs and respiratory ailments, and it’s beginning to show up in the United States in a product called Umcka. Tests in Europe show it may be especially useful against sore throats and bronchitis. (In a 2003 study, three out of four kids with sore throats who were given the supplement experienced rapid recovery, compared with only one in three offered a sugar pill.) Recent findings suggest pelargonium may speed up the motion of cilia, the tiny hairlike structures in your nasal passages and lungs that capture and eject invading bugs.

Worth a try for: Bronchitis and sore throats.

How to do it: Umcka ColdCare is the most widely available supplement that contains Pelargonium sidoides. Take it at the first sign of a cold and for 2 days after symptoms subside.

Probiotics
These friendly bacteria that turn milk into yogurt can help keep your defenses in top form, says Pat Baird, RD, author of Be Good to Your Gut. Upwards of 70 percent of the immune cells that produce antibodies live in the lining of your digestive tract. Keeping them in peak shape may help you battle colds and flu. In a recent study, German researchers gave 479 volunteers vitamin supplements either with or without probiotics. Those who took the probiotics for at least 3 months reduced the duration of their colds by almost 2 days and the severity of symptoms by about 20 percent.

Worth a try for: Boosting immunity.

How to do it: Although probiotics are sold in capsule form in the supplement aisle, a cheaper, tastier option is to eat yogurt or kefir, a milk beverage made with live cultures. Different brands have different cultures; what matters most is that their bacteria can survive in your colon. That’s true for most of the bacteria used in kefir, Baird says; for yogurt, look for brands that say “live and active culture” on the label.

Vitamin C
It became popular thanks to Nobel Prize–winning scientist Linus Pauling, who was sure the vitamin could ward off colds. Eventually, enthusiasm cooled (maybe it’s no coincidence that Pauling won his Nobels in chemistry and peace, not biology). Most evidence shows vitamin C doesn’t prevent colds, says Jane Higdon, a research associate at Linus Pauling Institute at Oregon State University in Corvallis. But, she adds, some studies show that if you take vitamin C at the first sign of a cold, it may shorten the duration by about a day.

Worth a try for: Getting rid of a cold faster.

How to do it: If you take a multivitamin and eat plenty of fruits and veggies daily, you’re probably already getting enough vitamin C. If not, take a supplement at the first sign of a cold. Don’t pop more than 400 milligrams, though; the extra will just wash out of your system.

Zinc
By all rights, this mineral should help fight off the sniffles. “Cold viruses gain a foothold in the nose by latching onto uniquely shaped molecules called ICAM-1,” explains Murray Grossan, MD, an ear, nose, and throat specialist at Cedars-Sinai Hospital in Los Angeles. “Zinc binds to the same molecules, which should help prevent cold viruses from attaching.” In fact, a 2003 study at the Cleveland Clinic found that zinc nasal spray shortened the duration of cold symptoms from 6 days to 4.3. Still, other evidence is decidedly mixed. In a review of 14 well-designed studies, 6 showed that zinc helped; the others said it didn’t. “So the jury is still out,” says infectious-diseases specialist Sherif Mossad, MD, of the Cleveland Clinic. There’s another thing you should know: Zinc lozenges can deaden your sense of taste. Also, some people using zinc nasal sprays have reported permanently losing their sense of smell, though a connection has not been proven.

Worth a try for: Easing cold symptoms. May also block cold viruses.

How to do it: Start using within 24 hours of the first sign of a cold. Follow package directions.