As we head into the holidays, a gift that many of us wish for is a strong immune system to protect us not only from serious illness, but also from wintry coughs and sniffles. Robust immunity rests on three pillars, research shows: getting at least seven hours of sleep a night to allow immune functions to reboot; daily exercise to stimulate the production of white blood cells that fight off harmful bacteria and viruses; and plant-based foods to supply the antioxidants and phytochemicals needed to reduce inflammation and keep cells humming happily.

In addition, we can enhance immunity by adding specific adaptogens and mushroom powders into our daily routine. These study-proven substances perform specific functions in the immune system that boost our resistance to illness. As powders, they can be easily added into drinks or foods, and they can also be taken as tinctures or pills.

Modulating Immunity with Adaptogens

Used for millennia in China and India, adaptogens are plants that keep the body in balance by helping it adapt to stress. They interact with the hypothalamic-pituitary-adrenal axis, a complex system of glands, hormones and receptors that helps manage homeostasis, stress responses and energy metabolism. “Adaptogens are a great way to boost immunity, especially if you are constantly sick and run down due to feeling stressed,” says Heather Hanks, a Plymouth, Michigan, nutritionist with USA Rx. Adaptogens typically take two or three weeks to become effective; follow package directions for proper dosage.

Astragalus (Astragalus membranaceus), an herb called locoweed in the U.S., boosts immune function by increasing natural killer cell activity and enhancing the function of macrophages, the “immune sentinels” that reside in tissues. A recent review suggests that long-term use of astragalus might help prevent colds, and taking it for up to six weeks may relieve seasonal allergy symptoms such as runny nose, itching and sneezing. It has also been shown to improve recovery after illness, disease or prolonged stress and to help post-chemotherapy patients regain health. Polish researchers found that rowing team athletes given 500 milligrams of astragalus root extract each day for six weeks had immune systems that recovered faster after strenuous exercise.

Panax Ginseng, a perennial plant from East Asia, keeps the immune system in balance by regulating its components, including macrophages, dendritic cells and both T and B cells. It improves resistance to illness and microbial attacks, helps counter stress, controls inflammation, improves cognitive functions and has been found effective in the treatment of cancer, neurodegenerative disorders, insulin resistance and hypertension.

Tulsi (Ocimum tenuiflorum), also known as holy basil, “enhances the immune response, protects the body against bacterial and viral infection and promotes clear and comfortable breathing,” says Ameya Duprey, a certified Ayurvedic practitioner in Nevada City, California. Studies show that it also helps prevent liver, kidney and brain injury by protecting against the genetic, immune and cellular damage caused by pesticides, pharmaceuticals and industrial chemicals.

The Marvel of Medicinal Mushrooms

Used medicinally since at least 3,000 BCE, certain mushrooms have been found to have antimicrobial, anti-inflammatory, cardiovascular-protective, anti-diabetic, liver-protective and anticancer properties. They are usually not cooked, but rather taken as a powder that can be added to foods like smoothies, cereals and stir-fries.

Reishi mushrooms increase the activity of killer cells and lower inflammation in white cells, warding off infections. “They are used by cancer patients, as they support a healthy immune system, have antioxidant properties and may prevent or treat infections,” says Linda Strause, Ph.D., an adjunct professor of human nutrition at University of California San Diego, whose husband with brain cancer was encouraged to take the mushrooms as a supplement.

Cordyceps (Cordyceps sinensi) is harvested from the larvae of caterpillars in the high Himalayas. In a randomized, eight-week Korean study of 79 adults, supplementing with 1.7 grams of cordyceps extract daily led to a significant 38 percent increase in the activity of natural killer cells that protect against infection. It has been used traditionally to treat fatigue, sexual dysfunction, asthma, kidney problems, high blood pressure and weak hearts.

Turkey tail (Trametes versicolor) contains a compound called polysaccharide-K that stimulates the immune system. It also acts as a prebiotic, which promotes the health of the gut microbiome, a key player in immunity. A Harvard Medical School study of 22 healthy people found that taking 3,600 milligrams of polysaccharopeptide extracted from turkey tail mushrooms each day led to beneficial changes in gut bacteria and suppressed the growth of problematic E. coli and shigella bacteria.

Health writer Ronica O’Hara can be contacted at [email protected].