Sauerkraut: A spoonful daily is the best preventative of colds and the flu. If you didn't make it last fall, it's not too late to do it now. It's ready to eat in a few days. Here's a free video showing how. Store bought doesn't work as it has been pasteurized.

Ginger has shown activity against numerous infectious pathogens. Most notably, fresh ginger inhibits viruses that commonly cause respiratory infections. Journal Ethnopharmacol. 2013 Jan 9;145(1):146-51. doi: 10.1016/j.jep.2012.10.043. Epub 2012 Nov 1.

Garlic has been used to prevent infection for thousands of years; and it still works! No need to upset your stomach (and loved ones) by eating it raw; cooked garlic retains its antibacterial powers, so long as you eat enough of it. During plague times, some healers wore a stiff cone of paper or bark stuffed with garlic and spices (cinnamon, cloves, nutmeg) tied over the nose to ward off contagion. That's a little cumbersome for modern times, but inhaling the aroma of a cup of spicy chai tea sweetened with garlic honey could help you stay well.

Roots — like beets, carrots, sweet potatoes, rutabaga (domestic maca), and burdock — are foundational for immune health. I love them roasted and eat them daily. Immune A Go Go Soup from my book Breast Cancer? Breast Health! is full of roots and immune-enhancing foods.

Dark leafy greens, including infusions of nettle, comfrey, and oatstraw, supply the minerals the immune system needs to produce antibodies. I drink a quart of nourishing herbal infusion every day; plus I eat a half cup of well-cooked greens daily. My freezer is a treasure chest of greens ready to heat and eat: amaranth, lambs quarter, kale, beet greens, collards, turnip greens, and chard.

Miso soup with seaweed and wild mushrooms is an easy, delicious way to keep your immune system strong and healthy. Pour boiling water over any dried seaweed and dried mushrooms. Allow to sit for at least an hour, or overnight. Pour rehydrated seaweed and mushrooms, plus soaking water into a pan and heat. Add miso.

These Nutrients Build Immunity

Carotenes strengthen and activate all parts of the immune system, especially the thymus — the "master gland of immunity." A half-cup of dandelion greens, two cups of nettle infusion, a small baked sweet potato, or two large cooked carrots or beets is a "dose;" but ten times that much can be consumed safely. Repeated doses provide a cumulative effect.

Selenium is a trace mineral with special abilities for building a healthy immune system. Best sources are organic garlic, medicinal mushrooms, and astragalus.

Zinc helps build energetic white blood cells, which help eliminate bacterial infections like bronchitis, sinus infections, and sore throat. Best sources are echinacea, nettles, and seaweed. I keep a bag of zinc-enriched lozenges on hand in the winter as zinc is most effective when in direct contact with respiratory tissues.

The B-vitamin complex, especially B6 (pyridoxine), is critical to immune system health. Best sources are potato skins, broccoli, prunes, and lentils.

Vitamin C is critical for warding off respiratory tract infections, including the common cold. Real vitamin C, from food. Not ascorbic acid from a laboratory. Even a single fresh green leaf supplies more and better vitamin C than any supplement. Think rose hips. Think pine needles. Think winter dandelion leaves. Think garlic mustard and winter cress. Look outside. Munch the green you see.