This herb has been found to cut the duration of a cold by 1.4 days, and it can even decrease your odds of falling sick in the first place by 58 percent. If you feel like you’re coming down with something, take 900 to 1,800 milligrams per day in three doses, says Fred Lisanti, N.D., L.Ac. Look for easy-to-swallow Nature’s Way standardized capsules ($25 for 60, vitaminshoppe.com).
Scoring the recommended daily dosage (500 milligrams) of this nutrient will help your cells fight off infection, according to Lise Alschuler, N.D., fellow of the American Board of Naturopathic Oncology. Munch on fresh golden kiwi (90 milligrams per serving) or brussels sprouts (80 milligrams). If you feel under the weather, up your intake to 500 milligrams every two hours. We dig American Health’s Ester-C with Citrus Bioflavinoids, which comes in pill, liquid and powder forms ($10–$43, Vitamin Shoppe locations).
You’ve heard about how this type of “good” bacteria can aid digestion, but it’s equally beneficial for your immune system. Even though the daily quota of 3 to 5 billion colony-forming units sounds massive, it’s doable if you reach for fermented dairy (yogurt, kefir) or pills, such as Now Foods Acidophilus tablets ($11 for 100, shop.nowfoods.com).
Taking a supplement of AHCC (Active Hexose Correlated Compound) every day may activate your body’s most potent white blood cells and increase production of the “messenger chemicals” that help immunity cells interact, say researchers from universities in Japan and the Yale School of Medicine. Try Host Defense Stamets 7 capsules for starters ($38, fungi.com).
The RDA is 600 IUs, but most holistic practitioners say women need 1,000 to 2,000 IUs. If your levels are low, “your immune cells may work more slowly and may not reproduce as quickly,” says Paul S. Anderson, N.D., a physician in Seattle. Your doctor can check during your next blood test. If you need more, use a combo of vitamin D3 supplements and time outside to remedy any deficiencies. (Spending just 15 minutes in direct midday sunshine can make a noticeable impact!) Country Life makes a certified gluten-free variety derived from a non–fish liver source ($8 for 200, Whole Foods stores).
Rich in antioxidant flavonoids known as anthocyanins, this immunity booster can cut short the flu by as much as four days, research suggests. Look for the extract in tablet, lozenge, or syrup form; Sambucol makes a surprisingly tasty liquid ($13, sambucol.com). Label guidelines will give you enough for general immune support, while a double dose can keep a pesky cold from becoming something more serious.