We all know the basics for reducing exposure to colds and flu: Wash your hands, avoid touching your face, and avoid being exposed to people who are already ill.
But there are other, highly effective measures we can take to protect ourselves.
The first one that probably comes to mind is the influenza vaccine. But here's what you need to know: the flu vaccine is not very effective.
An independent analysis of flu vaccine studies by Cochrane – a non-profit, non-government organization that organizes medical research information – found that under typical conditions, according to randomized controlled trials, vaccination reduced seasonal influenza rates from 2.3% to 0.9%, and reduced the rate of influenza-like illness from 21.5% to 18.1% among healthy adults (ages 16-65).
In other words, 71 healthy adults need to be vaccinated to prevent one case of influenza, and 29 need to be vaccinated to prevent one flu-like illness.1
Staying safe from flu virus and colds
Those of us who eat healthfully need not worry about the dangers of the flu. Excellent nutrition can reduce our vulnerability to infection and reduce the length and severity of illness if we do become infected.
Many micronutrients are required to support proper function of the immune system, and phytochemicals from colorful produce have additional anti-microbial and immune-boosting effects.
Make sure your diet includes the following immune boosting superfoods.
Mushrooms
Mushroom polysaccharides called beta-glucans have a unique ability to activate the body’s natural immune defenses.2,3 Additional phytochemicals in mushrooms, such as the antioxidant ergothioneine, and mushroom lectins, also have health-promoting properties.
Reishi and shiitake mushrooms enhance activity of natural killer (NK) cells, which attack cancerous and virus-infected cells.4,5 Shiitake mushrooms protect against influenza infection in animal studies.6-8
Fortunately, it is not only exotic mushrooms that benefit immune cell function. Dendritic cells are another type of immune cell that protects the respiratory tract, and their activity is also enhanced by white button mushroom phytochemicals.9
The effect of mushrooms on human immune function has been investigated in two interesting studies, one on white button mushrooms and one on shiitake mushrooms.
In both studies, the mushroom group showed an increase in immunoglobulin A secretion in saliva compared to the placebo group.
Immunoglobulins are antibodies secreted in the digestive tract to protect us against infection, and this component of immune function was enhanced by eating mushrooms.10,11
Mushrooms should only be eaten cooked. Several raw culinary mushrooms contain a potentially harmful compound called agaritine, and cooking mushrooms significantly reduces the agaritine content.12,13
Because various mushrooms have differing and profound immune system and anti-cancer benefits, I also recommend taking a mixed mushroom supplement containing 9 well-documented protective species.
Cruciferous vegetables
In addition to their well-known anti-cancer effects, cruciferous derived phytochemicals (isothiocyanates, such as sulforaphane, and indole-3-carbinol) also promote good immune system function and have antimicrobial properties.14-16
For example, interesting research on intestinal immunity has suggested that cruciferous vegetable phytochemicals are an important component of immune system function by maintaining adequate numbers of immune cells in the gut called intestinal epithelial lymphocytes.17
Cruciferous vegetable phytochemicals may also enhance interferon activity, which is an important component of the body’s antiviral response.14,15,18
To maximize isothiocyanates (ITCs), chop cruciferous vegetables finely, eat them raw and chew them well. The enzyme that converts glucosinolates to ITCs (called myrosinase) is activated by disrupting the plant cells and deactivated by heat.
However, you can still get ITCs from your cooked cruciferous vegetables. Chop them finely before you begin to cook, and add some raw cruciferous to the meal.
For instance, if you are eating cooked broccoli, add some shredded cabbage to your salad, which will provide some myrosinase to produce more ITC from the already cooked broccoli.
Gut bacteria have the myrosinase enzyme, so a small amount of ITCs from cooked cruciferous vegetables will be produced in the digestive tract as well.
Berries are powerful anti-cancer foods that also offer protection against viruses.
Antioxidants called flavonoids, which are abundant in berries, have antiviral and anti-inflammatory properties, as well as effects on immune cells that promote the resolution of inflammation.19-21
Studies suggest supplementing with flavonoid-rich elderberry juice, starting at the onset of symptoms, could shorten the duration of illness from flu.22,23
Randomized controlled trials have found that consuming blueberries, raspberries, or strawberries had a variety of immune health benefits, such as reducing oxidative stress in immune cells, increasing numbers of some types of immune cells including natural killer cells, and promoting growth of beneficial gut bacteria.24-29
Berries are also some of the many vitamin C-rich plant foods. Vitamin C protects immune cells from oxidative damage.30
Onions & Garlic
As with cruciferous vegetables, the same onion and garlic phytochemicals known for their anti-cancer effects have immune-supporting effects.31-33
In laboratory studies, garlic-derived phytochemicals such as allicin and S-allyl cysteine increase the activity of several immune cell types, including macrophages, T cells, and natural killer (NK) cells.34,35
A randomized controlled trial found that consuming crushed raw garlic upregulated genes involved in immune function and metabolizing and removing toxins.36
Garlic also has antiviral and antibacterial properties.37,38 More research is needed, but one study has provided evidence that garlic supplementation could help reduce the risk of the common cold.39
Like cruciferous vegetables, the active compounds in onions and garlic are produced when the plant cells are disrupted, so It’s best to chop them before eating raw and before they are heated when cooking.
Beans
Because beans, lentil, split peas, and other legumes are so high in indigestible carbohydrates, especially resistant starch, they provide exceptionally effective nourishment for the bacteria of the gut microbiome.40
The gut microbiome, in turn, promotes immune function, supports the integrity of the intestinal barrier, and has anti-inflammatory effects.41
Higher fiber intake has been linked to a lower risk of death from infectious diseases among Americans in their 50s, 60s, and 70s.42
An interesting study compared mice raised on a high-fiber or low-fiber diet. Researchers found that the high-fiber mice had better lung function and longer survival after infection with a flu virus compared to mice raised on a low-fiber diet, due to the diet’s beneficial effects on the microbiome.43
Many essential micronutrients support proper function of the immune system.
Vitamin D and zinc are important players in immune function, so maintaining adequate stores of these micronutrients will also help to protect against colds and flus.
Since vitamin D is not readily available in the food supply, and zinc is not highly absorbed from plant foods, supplements are a good choice.
I recommend a mixed mushroom supplement to increase mushroom phytochemical quantity and variety. Additional plant extracts, such as astragalus, elderberry, green tea, and curcumin may also be helpful for immune support.
As the weather gets colder, we tend to become more sedentary. But it’s important to carve out time to move your body.
The research suggests regular exercise boosts immunity, leading to fewer and less severe respiratory illnesses.44
Exercise is also an effective mode of stress relief. Chronic stress suppresses immune function and is linked to greater susceptibility to upper respiratory infections.45,46
Sleep
The immune system has a circadian rhythm, prioritizing different processes during waking and sleep times.47
Inadequate sleep and circadian misalignment are associated with all kinds of health problems, including diabetes, heart disease, and weight gain, in addition to compromised immune function.48,49
Practice good sleep hygiene. Finish eating dinner early for a long overnight fast, minimize your use of screens before bed, make your bedroom as dark as possible, and maintain a regular sleeping schedule to get more and better quality sleep.
Treating cold and flu symptoms
Most common cold remedies are ineffective, and some may even prolong the illness.
For example, mega doses of vitamin C do not prevent colds or reduce symptoms, and fever-reducing medications actually hinder the body’s attack on the infection.
In my book Super Immunity, I evaluate a number of common cold and flu remedies, such as cough medicines, nasal saline irrigation, echinacea, garlic, and zinc.
Don’t be alarmed if your cold symptoms last longer than you expect.
On average, patients report that their common cold symptoms last one and a half to two weeks.
In children, earaches tend to last anywhere from less than one day to 9 days, sore throat 2 to 7 days, cough up to 25 days, and the common cold 7 to 15 days.50
In time, the body will clear the virus on its own. Remember, over-the-counter medications merely mask symptoms, and may even impair healing.
However, if you experience a sudden worsening of symptoms, especially including labored breathing, or a fever above 103 degrees for three days, then it is time to call the doctor.
The bottom line
As your diet improves, you will be less likely to become ill, and if you do, you will recover more quickly.
This year, to protect yourself against cold and flu, get enough sleep, avoid putting your hands near your nose or mouth, and eat healthfully.
A nutrient-rich diet provides your body with a spectrum of immunity-boosting phytochemicals that also protect against heart disease, diabetes and cancer.
References
Demicheli V, Jefferson T, Ferroni E, et al. Vaccines for preventing influenza in healthy adults.Cochrane Database Syst Rev 2018, 2:CD001269.
Borchers AT, Krishnamurthy A, Keen CL, et al. The immunobiology of mushrooms.Exp Biol Med (Maywood) 2008, 233:259-276.
Akramiene D, Kondrotas A, Didziapetriene J, Kevelaitis E. Effects of beta-glucans on the immune system.Medicina (Kaunas) 2007, 43:597-606.
Wachtel-Galor S, Yuen J, Buswell JA, Benzie IFF: Ganoderma lucidum (Lingzhi or Reishi): A Medicinal Mushroom. In Herbal Medicine: Biomolecular and Clinical Aspects. 2nd edition. Edited by Benzie IFF, Wachtel-Galor S. Boca Raton (FL)2011
Yamaguchi Y, Miyahara E, Hihara J. Efficacy and safety of orally administered Lentinula edodes mycelia extract for patients undergoing cancer chemotherapy: a pilot study.American Journal of Chinese Medicine 2011, 39:451-459.
Ciric L, Tymon A, Zaura E, et al. In vitro assessment of shiitake mushroom (Lentinula edodes) extract for its antigingivitis activity.J Biomed Biotechnol 2011, 2011:507908.
Rincao VP, Yamamoto KA, Ricardo NM, et al. Polysaccharide and extracts from Lentinula edodes: structural features and antiviral activity.Virol J 2012, 9:37.
Suzuki F, Suzuki C, Shimomura E, et al. Antiviral and interferon-inducing activities of a new peptidomannan, KS-2, extracted from culture mycelia of Lentinus edodes.Journal of Antibiotics 1979, 32:1336-1345.
Ren Z, Guo Z, Meydani SN, Wu D. White button mushroom enhances maturation of bone marrow-derived dendritic cells and their antigen presenting function in mice.Journal of Nutrition 2008, 138:544-550.
Jeong SC, Koyyalamudi SR, Pang G. Dietary intake of Agaricus bisporus white button mushroom accelerates salivary immunoglobulin A secretion in healthy volunteers.Nutrition 2012, 28:527-531.
Dai X, Stanilka JM, Rowe CA, et al. Consuming Lentinula edodes (Shiitake) Mushrooms Daily Improves Human Immunity: A Randomized Dietary Intervention in Healthy Young Adults.J Am Coll Nutr 2015, 34:478-487.
Schulzova V, Hajslova J, Peroutka R, et al. Influence of storage and household processing on the agaritine content of the cultivated Agaricus mushroom.Food Additives and Contaminants 2002, 19:853-862.
Roupas P, Keogh J, Noakes M, et al. Mushrooms and agaritine: A mini-review.Journal of Functional Foods 2010, 2:91-98.
Xue L, Pestka JJ, Li M, et al. 3,3'-Diindolylmethane stimulates murine immune function in vitro and in vivo.J Nutr Biochem 2008, 19:336-344.
Sepkovic DW, Raucci L, Stein J, et al. 3,3'-Diindolylmethane increases serum interferon-gamma levels in the K14-HPV16 transgenic mouse model for cervical cancer.In Vivo 2012, 26:207-211.
Linus Pauling Institue, Oregon State University. Micronutrient Information Center. Indole-3-Carbinol. [https://lpi.oregonstate.edu/mic/dietary-factors/phytochemicals/indole-3-carbinol]
Hooper LV. You AhR what you eat: linking diet and immunity.Cell 2011, 147:489-491.
Chen WC, Huang CH, Liu W, Lee JC. Sulforaphane suppresses dengue virus replication by inhibition of dengue protease and enhancement of antiviral interferon response through Nrf2-mediated heme oxygenase-1 induction.Antiviral Res 2022, 207:105400.
Naithani R, Huma LC, Holland LE, et al. Antiviral activity of phytochemicals: a comprehensive review.Mini Rev Med Chem 2008, 8:1106-1133.
Hosseinzade A, Sadeghi O, Naghdipour Biregani A, et al. Immunomodulatory Effects of Flavonoids: Possible Induction of T CD4+ Regulatory Cells Through Suppression of mTOR Pathway Signaling Activity.Front Immunol 2019, 10:51.
Patel S, Vajdy M. Induction of cellular and molecular immunomodulatory pathways by vitamin A and flavonoids.Expert Opin Biol Ther 2015, 15:1411-1428.
Roxas M, Jurenka J. Colds and influenza: a review of diagnosis and conventional, botanical, and nutritional considerations.Altern Med Rev 2007, 12:25-48.
Zakay-Rones Z, Thom E, Wollan T, Wadstein J. Randomized study of the efficacy and safety of oral elderberry extract in the treatment of influenza A and B virus infections.Journal of International Medical Research 2004, 32:132-140.
Franck M, de Toro-Martín J, Garneau V, et al. Effects of Daily Raspberry Consumption on Immune-Metabolic Health in Subjects at Risk of Metabolic Syndrome: A Randomized Controlled Trial.Nutrients 2020, 12.
Nair AR, Mariappan N, Stull AJ, Francis J. Blueberry supplementation attenuates oxidative stress within monocytes and modulates immune cell levels in adults with metabolic syndrome: a randomized, double-blind, placebo-controlled trial.Food Funct 2017, 8:4118-4128.
McAnulty LS, Collier SR, Landram MJ, et al. Six weeks daily ingestion of whole blueberry powder increases natural killer cell counts and reduces arterial stiffness in sedentary males and females.Nutr Res 2014, 34:577-584.
Zunino SJ, Storms DH, Freytag TL, et al. Dietary strawberries increase the proliferative response of CD3/CD28-activated CD8⁺ T cells and the production of TNF-α in lipopolysaccharide-stimulated monocytes from obese human subjects.Br J Nutr 2013, 110:2011-2019.
Guglielmetti S, Fracassetti D, Taverniti V, et al. Differential modulation of human intestinal bifidobacterium populations after consumption of a wild blueberry (Vaccinium angustifolium) drink.J Agric Food Chem 2013, 61:8134-8140.
McAnulty LS, Nieman DC, Dumke CL, et al. Effect of blueberry ingestion on natural killer cell counts, oxidative stress, and inflammation prior to and after 2.5 h of running.Appl Physiol Nutr Metab 2011, 36:976-984.
Oregon State University. Linus Pauling Institute: Micronutrient Information Center. Vitamin C. [http://lpi.oregonstate.edu/infocenter/vitamins/vitaminC/index.html]
Lau BH, Yamasaki T, Gridley DS. Garlic compounds modulate macrophage and T-lymphocyte functions.Molecular Biotherapy 1991, 3:103-107.
Hassan ZM, Yaraee R, Zare N, et al. Immunomodulatory affect of R10 fraction of garlic extract on natural killer activity.Int Immunopharmacol 2003, 3:1483-1489.
Weber ND, Andersen DO, North JA, et al. In vitro virucidal effects of Allium sativum (garlic) extract and compounds.Planta Medica 1992, 58:417-423.
Rodrigues C, Percival SS. Immunomodulatory Effects of Glutathione, Garlic Derivatives, and Hydrogen Sulfide.Nutrients 2019, 11.
Arreola R, Quintero-Fabian S, Lopez-Roa RI, et al. Immunomodulation and anti-inflammatory effects of garlic compounds.J Immunol Res 2015, 2015:401630.
Charron CS, Dawson HD, Albaugh GP, et al. A Single Meal Containing Raw, Crushed Garlic Influences Expression of Immunity- and Cancer-Related Genes in Whole Blood of Humans.J Nutr 2015, 145:2448-2455.
Bhatwalkar SB, Mondal R, Krishna SBN, et al. Antibacterial Properties of Organosulfur Compounds of Garlic (Allium sativum).Front Microbiol 2021, 12:613077.
Rouf R, Uddin SJ, Sarker DK, et al. Antiviral potential of garlic (Allium sativum) and its organosulfur compounds: A systematic update of pre-clinical and clinical data.Trends Food Sci Technol 2020, 104:219-234.
Lissiman E, Bhasale AL, Cohen M. Garlic for the common cold.Cochrane Database of Systematic Reviews 2014.
Sonnenburg JL, Backhed F. Diet-microbiota interactions as moderators of human metabolism.Nature 2016, 535:56-64.
Shi N, Li N, Duan X, Niu H. Interaction between the gut microbiome and mucosal immune system.Mil Med Res 2017, 4:14.
Park Y, Subar AF, Hollenbeck A, Schatzkin A. Dietary fiber intake and mortality in the NIH-AARP diet and health study.Arch Intern Med 2011, 171:1061-1068.
Trompette A, Gollwitzer ES, Pattaroni C, et al. Dietary Fiber Confers Protection against Flu by Shaping Ly6c(-) Patrolling Monocyte Hematopoiesis and CD8(+) T Cell Metabolism.Immunity 2018, 48:992-1005 e1008.
Nieman DC, Henson DA, Austin MD, Sha W. Upper respiratory tract infection is reduced in physically fit and active adults.British Journal of Sports Medicine 2011, 45:987-992.
Vitlic A, Lord JM, Phillips AC. Stress, ageing and their influence on functional, cellular and molecular aspects of the immune system.Age (Dordr) 2014, 36:9631.
Pedersen A, Zachariae R, Bovbjerg DH. Influence of psychological stress on upper respiratory infection--a meta-analysis of prospective studies.Psychosom Med 2010, 72:823-832.
Geiger SS, Fagundes CT, Siegel RM. Chrono-immunology: progress and challenges in understanding links between the circadian and immune systems.Immunology 2015, 146:349-358.
Opp MR. Sleeping to fuel the immune system: mammalian sleep and resistance to parasites.BMC Evol Biol 2009, 9:8.
Almeida CM, Malheiro A. Sleep, immunity and shift workers: A review.Sleep Sci 2016, 9:164-168.
Thompson M, Vodicka TA, Blair PS, et al. Duration of symptoms of respiratory tract infections in children: systematic review.British Medical Journal 2013, 347.
Joel Fuhrman, M.D. is a board-certified family physician, seven-time New York Times bestselling author and internationally recognized expert on nutrition and natural healing, who specializes in preventing and reversing disease through nutritional methods. Dr. Fuhrman coined the term “Nutritarian” to describe his longevity-promoting, nutrient dense, plant-rich eating style.
For over 30 years, Dr. Fuhrman has shown that it is possible to achieve sustainable weight loss and reverse heart disease, diabetes and many other illnesses using smart nutrition. In his medical practice, and through his books and PBS television specials, he continues to bring this life-saving message to hundreds of thousands of people around the world.
During Cold & Flu Season, Protect Yourself by Eating Right
March 04, 2025 by Joel Fuhrman, MD
We all know the basics for reducing exposure to colds and flu: Wash your hands, avoid touching your face, and avoid being exposed to people who are already ill.
But there are other, highly effective measures we can take to protect ourselves.
The first one that probably comes to mind is the influenza vaccine. But here's what you need to know: the flu vaccine is not very effective.
An independent analysis of flu vaccine studies by Cochrane – a non-profit, non-government organization that organizes medical research information – found that under typical conditions, according to randomized controlled trials, vaccination reduced seasonal influenza rates from 2.3% to 0.9%, and reduced the rate of influenza-like illness from 21.5% to 18.1% among healthy adults (ages 16-65).
In other words, 71 healthy adults need to be vaccinated to prevent one case of influenza, and 29 need to be vaccinated to prevent one flu-like illness.1
Staying safe from flu virus and colds
Those of us who eat healthfully need not worry about the dangers of the flu. Excellent nutrition can reduce our vulnerability to infection and reduce the length and severity of illness if we do become infected.
Many micronutrients are required to support proper function of the immune system, and phytochemicals from colorful produce have additional anti-microbial and immune-boosting effects.
Make sure your diet includes the following immune boosting superfoods.
Mushrooms
Mushroom polysaccharides called beta-glucans have a unique ability to activate the body’s natural immune defenses.2,3 Additional phytochemicals in mushrooms, such as the antioxidant ergothioneine, and mushroom lectins, also have health-promoting properties.
Reishi and shiitake mushrooms enhance activity of natural killer (NK) cells, which attack cancerous and virus-infected cells.4,5 Shiitake mushrooms protect against influenza infection in animal studies.6-8
Fortunately, it is not only exotic mushrooms that benefit immune cell function. Dendritic cells are another type of immune cell that protects the respiratory tract, and their activity is also enhanced by white button mushroom phytochemicals.9
The effect of mushrooms on human immune function has been investigated in two interesting studies, one on white button mushrooms and one on shiitake mushrooms.
In both studies, the mushroom group showed an increase in immunoglobulin A secretion in saliva compared to the placebo group.
Immunoglobulins are antibodies secreted in the digestive tract to protect us against infection, and this component of immune function was enhanced by eating mushrooms.10,11
Mushrooms should only be eaten cooked. Several raw culinary mushrooms contain a potentially harmful compound called agaritine, and cooking mushrooms significantly reduces the agaritine content.12,13
Related: Mighty Mushrooms: Boost Immune Function and Brain Health and Guard Against Cancer
Because various mushrooms have differing and profound immune system and anti-cancer benefits, I also recommend taking a mixed mushroom supplement containing 9 well-documented protective species.
Cruciferous vegetables
In addition to their well-known anti-cancer effects, cruciferous derived phytochemicals (isothiocyanates, such as sulforaphane, and indole-3-carbinol) also promote good immune system function and have antimicrobial properties.14-16
For example, interesting research on intestinal immunity has suggested that cruciferous vegetable phytochemicals are an important component of immune system function by maintaining adequate numbers of immune cells in the gut called intestinal epithelial lymphocytes.17
Cruciferous vegetable phytochemicals may also enhance interferon activity, which is an important component of the body’s antiviral response.14,15,18
To maximize isothiocyanates (ITCs), chop cruciferous vegetables finely, eat them raw and chew them well. The enzyme that converts glucosinolates to ITCs (called myrosinase) is activated by disrupting the plant cells and deactivated by heat.
However, you can still get ITCs from your cooked cruciferous vegetables. Chop them finely before you begin to cook, and add some raw cruciferous to the meal.
For instance, if you are eating cooked broccoli, add some shredded cabbage to your salad, which will provide some myrosinase to produce more ITC from the already cooked broccoli.
Gut bacteria have the myrosinase enzyme, so a small amount of ITCs from cooked cruciferous vegetables will be produced in the digestive tract as well.
Related: Cruciferous Vegetables Offer Great Cancer Protection
Berries
Berries are powerful anti-cancer foods that also offer protection against viruses.
Antioxidants called flavonoids, which are abundant in berries, have antiviral and anti-inflammatory properties, as well as effects on immune cells that promote the resolution of inflammation.19-21
Studies suggest supplementing with flavonoid-rich elderberry juice, starting at the onset of symptoms, could shorten the duration of illness from flu.22,23
Randomized controlled trials have found that consuming blueberries, raspberries, or strawberries had a variety of immune health benefits, such as reducing oxidative stress in immune cells, increasing numbers of some types of immune cells including natural killer cells, and promoting growth of beneficial gut bacteria.24-29
Berries are also some of the many vitamin C-rich plant foods. Vitamin C protects immune cells from oxidative damage.30
Onions & Garlic
As with cruciferous vegetables, the same onion and garlic phytochemicals known for their anti-cancer effects have immune-supporting effects.31-33
In laboratory studies, garlic-derived phytochemicals such as allicin and S-allyl cysteine increase the activity of several immune cell types, including macrophages, T cells, and natural killer (NK) cells.34,35
A randomized controlled trial found that consuming crushed raw garlic upregulated genes involved in immune function and metabolizing and removing toxins.36
Garlic also has antiviral and antibacterial properties.37,38 More research is needed, but one study has provided evidence that garlic supplementation could help reduce the risk of the common cold.39
Like cruciferous vegetables, the active compounds in onions and garlic are produced when the plant cells are disrupted, so It’s best to chop them before eating raw and before they are heated when cooking.
Beans
Because beans, lentil, split peas, and other legumes are so high in indigestible carbohydrates, especially resistant starch, they provide exceptionally effective nourishment for the bacteria of the gut microbiome.40
The gut microbiome, in turn, promotes immune function, supports the integrity of the intestinal barrier, and has anti-inflammatory effects.41
Higher fiber intake has been linked to a lower risk of death from infectious diseases among Americans in their 50s, 60s, and 70s.42
An interesting study compared mice raised on a high-fiber or low-fiber diet. Researchers found that the high-fiber mice had better lung function and longer survival after infection with a flu virus compared to mice raised on a low-fiber diet, due to the diet’s beneficial effects on the microbiome.43
Related: Your gut microbiome influences immune function (and beans keep it healthy)
Helpful supplements
Many essential micronutrients support proper function of the immune system.
Vitamin D and zinc are important players in immune function, so maintaining adequate stores of these micronutrients will also help to protect against colds and flus.
Since vitamin D is not readily available in the food supply, and zinc is not highly absorbed from plant foods, supplements are a good choice.
I recommend a mixed mushroom supplement to increase mushroom phytochemical quantity and variety. Additional plant extracts, such as astragalus, elderberry, green tea, and curcumin may also be helpful for immune support.
Please see my Product Recommendation Quiz for more information.
Related: Can supplements enhance immune function?
Exercise
As the weather gets colder, we tend to become more sedentary. But it’s important to carve out time to move your body.
The research suggests regular exercise boosts immunity, leading to fewer and less severe respiratory illnesses.44
Exercise is also an effective mode of stress relief. Chronic stress suppresses immune function and is linked to greater susceptibility to upper respiratory infections.45,46
Sleep
The immune system has a circadian rhythm, prioritizing different processes during waking and sleep times.47
Inadequate sleep and circadian misalignment are associated with all kinds of health problems, including diabetes, heart disease, and weight gain, in addition to compromised immune function.48,49
Practice good sleep hygiene. Finish eating dinner early for a long overnight fast, minimize your use of screens before bed, make your bedroom as dark as possible, and maintain a regular sleeping schedule to get more and better quality sleep.
Treating cold and flu symptoms
Most common cold remedies are ineffective, and some may even prolong the illness.
For example, mega doses of vitamin C do not prevent colds or reduce symptoms, and fever-reducing medications actually hinder the body’s attack on the infection.
In my book Super Immunity, I evaluate a number of common cold and flu remedies, such as cough medicines, nasal saline irrigation, echinacea, garlic, and zinc.
Read: Super Immunity
Don’t be alarmed if your cold symptoms last longer than you expect.
On average, patients report that their common cold symptoms last one and a half to two weeks.
In children, earaches tend to last anywhere from less than one day to 9 days, sore throat 2 to 7 days, cough up to 25 days, and the common cold 7 to 15 days.50
In time, the body will clear the virus on its own. Remember, over-the-counter medications merely mask symptoms, and may even impair healing.
However, if you experience a sudden worsening of symptoms, especially including labored breathing, or a fever above 103 degrees for three days, then it is time to call the doctor.
The bottom line
As your diet improves, you will be less likely to become ill, and if you do, you will recover more quickly.
This year, to protect yourself against cold and flu, get enough sleep, avoid putting your hands near your nose or mouth, and eat healthfully.
A nutrient-rich diet provides your body with a spectrum of immunity-boosting phytochemicals that also protect against heart disease, diabetes and cancer.
Joel Fuhrman, M.D. is a board-certified family physician, seven-time New York Times bestselling author and internationally recognized expert on nutrition and natural healing, who specializes in preventing and reversing disease through nutritional methods. Dr. Fuhrman coined the term “Nutritarian” to describe his longevity-promoting, nutrient dense, plant-rich eating style.
For over 30 years, Dr. Fuhrman has shown that it is possible to achieve sustainable weight loss and reverse heart disease, diabetes and many other illnesses using smart nutrition. In his medical practice, and through his books and PBS television specials, he continues to bring this life-saving message to hundreds of thousands of people around the world.