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While we tend to focus on immunity during cold and flu season, the past few years have taught us that keeping our natural defenses in top shape is—or should be—a year-round priority. All of the following immune health supplements can be taken daily, all year long, so pick the ones you are most likely to take every day. One other option: find a combination formula that includes some or all of these ingredients.
It’s one of the best immune health supplements out there, a safe, effective antioxidant that’s been shown to prevent and treat flu and other viral infections. Studies suggest that taking vitamin C frequently throughout the day, rather than in one concentrated dose, results in higher plasma levels. For maximum effectiveness, choose ascorbic acid in combination with bioflavonoids and other associated micronutrients.
Higher doses of ascorbic acid can cause stomach upset; buffered forms or liposomal vitamin C prevent this, and some research suggests that liposomal vitamin C is also better absorbed than traditional ascorbic acid. One form, called Ester-C, uses a proprietary, water-based process that creates a pH-neutral product that’s gentler on the stomach and has improved bioavailability. Whole food-based vitamin C supplements may also be easier to absorb, as they rely on body-ready fruits and veggies that are rich in vitamin C.
A number of studies have found that vitamin D boosts the body’s natural defenses, and helps ward off viruses that cause colds, flu, and respiratory illness. This immune health supplement should be taken daily during the winter, when sunshine is at a minimum and levels of this crucial substance can drop dramatically.
In addition to supporting overall immunity, vitamin D supplements may reduce risk of respiratory infections by 50 percent. Studies show a direct and dramatic impact of vitamin D on respiratory and lung health, including preventing viral and bacterial respiratory infection, asthma, and other conditions. The recommended form is vitamin D3, or cholecalciferol. Studies show that D3 converts to its active form faster than vitamin D2, and is significantly better at raising blood levels of vitamin D.
Used for thousands of years in traditional Chinese medicine, medicinal mushrooms are rich in polysaccharides and beta-glucans, both of which help protect against viruses and support overall immune function. Mushrooms are also high in L-ergothioneine and glutathione, extremely powerful antioxidants that protect against viruses and support the immune system.
Reishi, shiitake, maitake, and turkey tail mushrooms are widely used as immune health supplements, but even culinary mushrooms such as button and porcini have the same type of immunostimulatory compounds. Some studies also suggest that mushrooms are even more potent when taken with ashwagandha, an Ayurvedic herb that also promotes immune function.
Another immune-enhancing fungus related to the mushroom family is Cordyceps sinensis, which has been used for thousands of years in traditional Chinese and Tibetan medicine. It’s a bizarre fungus that grows on the bodies of caterpillars (modern versions are grown on grains, so they’re vegan). Cordyceps has powerful immunomodulatory effects and has been studied for its effects on the flu virus. Studies show that cordyceps has antiviral, anti-influenza properties, and appears to work in part by increasing the number of natural killer cells and the expression of proteins that regulate white blood cell activities.
Curcumin, the most active compound in turmeric, is a powerful anti-inflammatory and immune-supportive agent that can modulate the activation of T cells, B cells, macrophages, neutrophils, natural killer cells, and other components of the immune response. Because turmeric naturally contains as little as 2 percent curcumin, concentrated supplements may better a better source than food.
Additionally, because the spice is insoluble in water, curcumin is hard for the body to absorb—undissolved particles are too large to be absorbed through the intestinal wall into the bloodstream, so they’re excreted by the body. Most curcumin supplements include piperine from black pepper, which significantly increases bioavailability. Others may use technology—like coating curcumin molecules with substances that make them water-soluble, or using very tiny particles—to make curcumin more available.
Related: 10 Benefits of Turmeric and Curcumin
One caution: Curcumin can bind to iron and decrease its availability, so people with low iron status or anemia should check with their health care providers before taking any turmeric or curcumin product.
Zinc is a well-known immune health supplement — even mild deficiencies can suppress immune function. A review of studies examining vitamins and minerals for colds and flu treatment showed that 70 mg of zinc per day alleviated cough, sore throat, and fever if taken with 24 hours of the onset of symptoms. Zinc lozenges that also include elderberry can ease and shorten the duration of cold and flu symptoms. One warning: because excessive zinc can depress the immune system, the daily recommended dose of 70 mg should not be exceeded.
Related: 7 Benefits of Zinc
These live cultures found in yogurt and fermented foods are beneficial bacteria that improve immune function in the gut and fight off pathogens—significant, because the gut represents about 70 percent of the immune system. Studies show that probiotics work as immune health supplements by preventing pathogens from adhering to intestinal walls, enhancing the gut’s barrier function, modulating inflammation, and stimulating protective responses to pathogens. Other research suggests that probiotics specifically help prevent respiratory infections and the common cold. In one study, workers who took Lactobacillus reuteri (a specific probiotic strain that stimulate white blood cells) every day had less than half the sick leave of workers who didn’t. In another study, Lactobacillus acidophilus or a combination of L. acidophilus NCFM and Bifidobacterium animalis subsp lactis B1-07 helped alleviate cold and flu symptoms, including cough.
Related: The Benefits of Probiotics
Consider adding the following herbal immune health supplements to your daily regimen during cold and flu season to protect against pathogens. They work best when used at the first sign of illness, and should be kept on hand and taken immediately when first feeling sick.
- Studies show Korean ginseng boosts immunity, protects against colds and flu and shortens their duration, and can help the flu vaccine work better. Fermented forms tend to be absorbed faster and more consistently than non-fermented forms. Another herb called Siberian ginseng (Eleutherococcus senticosus) isn’t actually related to true ginseng but has similar immune-boosting antiviral activities.
- Andrographis, also called “Indian echinacea,” has been used in traditional medicine for thousands of years to protect against infection. Research shows that it can significantly improve symptoms of upper respiratory tract infections, and may even prevent them from occurring. In one study, Andrographis was twice as effective as a placebo at reducing cough, nasal discharge, headache, fever, sore throat, earache, fatigue, sleep disturbances, and other symptoms of respiratory tract infection. Andrographis may also prevent infection by the flu virus and can lessen the severity and duration of the flu. Some studies used a specific product called Kan Jang, a Scandinavian cold remedy that combines Andrographis with Siberian ginseng.
- Elderberry (Sambucus nigra), as a standardized extract, has been shown to fight bronchitis by rendering the virus noninfectious, and may also protect against the flu virus. Other studies show a significant reduction of cold duration and severity after taking Sambucus extracts. Elderberry can be taken daily throughout the year.
Folk medicine 6 safe, simple remedies
1. Rub garlic on your feet. The idea is that the active compounds in garlic penetrate the skin and are absorbed into the bloodstream. (Test it: if you rub garlic on your feet, you’ll taste it in your mouth in about 15 minutes.) Here’s how to do it: thinly slice several garlic cloves, layer on the bottom of the feet, wrap feet in plastic wrap, and cover with socks. You can also just eat garlic—finely mince 1–2 garlic cloves, drop in a small cup of water and chug it—or take garlic in capsule form. Studies show that a daily garlic supplement significantly reduces incidence and severity of colds and flu.
2. Gargle with apple cider vinegar. Raw, unpasteurized apple cider vinegar (ACV) contains probiotics and creates an acidic coating in the throat that deters viruses and bacteria. Mix a tablespoon in warm water and gargle; repeat several times a day. Or mix equal parts ACV and raw honey in a small jar, and take 1 tablespoon every hour (store in the refrigerator between doses).
You can also gargle with salt water: the briny solution soothes sore throat, promotes healing of irritated mucous membranes, and creates an environment that’s inhospitable to pathogens. Mix ½ teaspoon sea salt in a cup of warm water, gargle, and spit it out. Don’t overdo it; too much salt will irritate the throat.
3. Clean your ears with hydrogen peroxide. Some people hypothesize the cold virus enters the body through the ear canal, and cleaning the ears with hydrogen peroxide can halt replication of the virus. Pour 3 percent hydrogen peroxide solution in a dropper bottle, tilt your head to one side, and place several drops of hydrogen peroxide into the ear. Hold your head in place for about two minutes; you’ll feel a fizzing or bubbling sensation. Tilt your head to the other side and repeat. You can do this every couple of hours, or until there’s no more bubbling or fizzing when you add the drops. If nothing else, your ears will be clean. (If you’ve had a punctured eardrum or any ear surgeries, skip this option.)
4. Wear wet socks. This is a simple form of hydrotherapy, which is thought to clear blocked nasal passages and increase immune system activity by shocking the body into quickly increasing circulation. Before bed, soak your feet in a tub of hot water. At the same time, soak a pair of thin cotton socks in a bowl of ice water. Wring them out well, put them on your feet, cover with a heavy pair of wool socks, and crawl into bed. Your feet will start warming up quickly, and congestion should be relieved within about 30 minutes.
5. Drink ginger tea. It’s thought to decrease inflammation, thin mucus secretions, and clear nasal passages. Cayenne pepper, garlic, and other spicy and pungent foods also help. For a decongestant tea, combine ¼ cup sliced ginger root with 3 cups water, and add a clove of garlic and as much cayenne pepper as you can bear. Simmer, covered, for 20 minutes, then strain and sweeten with raw honey. You can also add onions, green tea bags, or apple slices—all are rich in quercetin, an antioxidant that reduces inflammation supports immune response, and acts as a natural antihistamine.
6. Eat chicken soup. The hot vapors from soup increase the temperature of the airways and promote secretions. Warm broth also calms and soothes inflamed membranes in the throat. Drinking any kind of soup also helps with hydration—the more liquid content, the better. [Editor’s note: Speaking of soup … see our recipe for Slow-Cooker French Onion Soup with Thyme below. It’s filled with immune-boosting powers.