A sick woman holding a mug and a tissue in autumn

Immune Boosters

By:
Maria Noël Groves, RH (AHG)
This content originally appeared on 

Forget hospitality! This season, cultivate the ability to be a bad host... to pathogens, that is. We are always surrounded by germs, but you can take simple steps to discourage them from setting up camp in your body and get them packing more quickly if they do show up like unwelcome house guests.

Lifestyle and Your Immune System

Before taking any supplements, consider two of the most important ways to boost your resistance naturally: Get a good night's sleep and wash your hands regularly. Researchers have found that sleeping less than seven hours triples your risk of catching a cold versus eight hours of shut-eye. People with poor sleep efficiency are more than five times more likely to get sick.

Meanwhile, hand washing helps prevent 20 percent of everyday infections like colds and 30 percent of diarrhea-related illness (nearly 60 percent for those with compromised immune systems).

Supplements for Immunity

  • Elderberry

    Both traditional use and scientific evidence support this berry's ability to prevent viral infections. Viruses hijack your cells and reprogram them to make more viruses, which allows the infection to spread more virulently. Elderberry works at least in part by binding to cell-receptor sites to block viruses, and other research suggests a similar benefit against bacteria.

    In a recent study of Australians on long, overseas flights, taking elderberry extract significantly reduced the duration and severity of colds compared to those taking a placebo, cutting both by more than half.

  • Echinacea

    This herb has a long history of use for infection, particularly bacterial infections and sepsis. It has many actions including mobilizing white blood cells to fight infection. In spite of being the subject of hundreds of clinical studies, the results on echinacea have been mixed, likely due to the range of species and extracts available, part of the plant used, dosage, and methodology.

    One review of a number of studies concluded that people were 55 percent more likely to experience a cold taking a placebo versus echinacea. Herbalists use relatively high doses of the fresh plant tincture--ideally the root--taken every waking hour or two from the first tickle of an infection until it passes. Echinacea extract numbs the tongue, doesn't taste great, may cause a flareup of autoimmune disease, and occasionally causes allergies in people who react to other daisy family plants.

  • Vitamin C

    Taking larger amounts of a vitamin C supplement may lead to shorter colds. Most studies examining the effects of the vitamin have used a dosage of 1 gram (g) per day, but researchers have recently found better results with higher amounts.

    Participants in two studies received daily vitamin C doses ranging from none (the placebo) up to 8 g. Both studies showed significant dose-response relationships, meaning that higher amounts of the vitamin led to shorter colds.

    "It would be worthwhile for individual common cold patients to test whether therapeutic 8 grams per day of vitamin C is beneficial for them," said researcher Harri Hemila, MD, PhD. "Self-dosing of vitamin C must be started as soon as possible after the onset of common cold symptoms to be most effective."

    Vitamin C is considered to be safe as a dietary supplement, but check with your healthcare practitioner before opting for large doses of any supplement.

  • Vitamin D

    According to the National Health and Nutrition Examination Survey, 77 percent of Americans fell short of the lowest normal blood levels for vitamin D. Several studies link low vitamin D levels to an increased risk and severity of infectious disease, including the flu, respiratory ailments, and immunodeficiency for both children and adults.

    The evidence for improved outcomes with vitamin D supplementation is mixed but promising. The recommended daily intake for vitamin D supplements is 600 to 800 IU, preferably of the more bioavailable vitamin D3.

  • Probiotics

    As a powerful team member of your immune system, probiotics produce organic compounds that increase intestinal acidity; this inhibits the reproduction of many disease-causing bacteria.

    Probiotic bacteria also produce substances called bacteriocins that act as natural antibiotics to kill undesirable microorganisms. Probiotic bacteria enhance overall immune function by boosting disease-fighting cells such as phagocytes, lymphocytes, and natural killer cells. The end result--when your probiotic microbiome is flourishing--is a system that is better able to fight off infection and disease.

    As just one example of how this immune boost plays out in the real world, consider the latest research on the common cold. Regular use of probiotics by schoolchildren makes colds less frequent, and when they do hit, the kids get over them more quickly and miss fewer school days. A yearlong study showed a 30 percent reduction in missed school days from simply taking probiotic supplements. Research documents similar benefits in adults.

Click to See Our Sources

"Antibacterial Activities of Bacteriocins: Application in Foods and Pharmaceuticals" by S-C Yang et al., Front Microbiol, 5/26/14

"Echinacea for Preventing and Treating the Common Cold" by M. Karsch-Volk et al., Cochrane Database Syst Rev, 2/14 

"Echinacea in the Prevention of Induced Rhinovirus Colds: A Meta-analysis" by R. Schoop et al., Clin Ther, 2/06

"How Much Vitamin D Do I Need to Take?" Vitamin D Council, www.VitaminDCouncil.org, 2017

"Inhibitory Activity of a Standardized Elderberry Liquid Extract Against Clinically-Relevant Human Respiratory Bacterial Pathogens and Influenza A and B Viruses" by C. Krawitz et al., BMC Complement Altern Med, 2011 

"Larger doses of vitamin C may lead to a greater reduction in common cold duration," University of Helsinki, 3/30/17

"Probiotics for Preventing Acute Upper Respiratory Tract Infections" by Q. Hao et al., Cochrane Database Syst Rev, 2/3/15

"Show Me the Science--Why Wash Your Hands?" Centers for Disease Control and Prevention, www.cdc.gov, 11/18/15

"Sleep Habits and Susceptibility to the Common Cold" by S. Cohen et al., Arch Intern Med, 1/12/09

"Vitamin D and Influenza" by M.E. Sundaram and L.A. Coleman, Adv Nutr, 8/12