Colds and Flu


What should I know about Colds and Influenza?

Colds and influenza are the two conditions that affect us on a yearly basis. While a minor irritation for most people, these two conditions can pose a major health threat to the very young, the elderly, and those who are immunocompromised. In fact, the flu is a leading cause of death in the elderly. Americans spend over one billion dollars annually on nonprescription treatments for coughs and colds, including antipyretics, antihistamines, cough preparations, and decongestants in various combinations. Although these agents may help the symptoms of colds and flu to subside gradually, they do not address the underlying condition, including immune and nutrition status. Also, many of the agents used conventionally for colds and flu may cause unwanted side effects such as insomnia, hyper-excitability, dry mouth, constipation, drowsiness, or interact with prescription medications. There are several reasons for the recommendation of natural therapeutic agents as a first line of defense or as a complement to drug therapy. These reasons include:

    Pre-existing conditions or medications may preclude traditional OTC therapy; Occupation may eliminate the choice of antihistamines or decongestants (pilot, truck driver); Patient may request a natural product due to belief system; Flu vaccination may not provide adequate immune support.

The common cold, also known as upper respiratory infection (URI), is an acute, self-limiting illness caused by a virus. URIs cause absenteeism from work, accounting for 45 million days of restricted activity in 1996. (1) Preschoolers have the highest rate of infection, experiencing 6-10 episodes per year, while adults average 2-4 colds per year. (2)

Although viruses account for the overwhelming proportion of cases with about 30-50 percent being caused by rhinoviruses (rhino = nose) and 10-15 percent being caused by coronaviruses (corona = crown), (3) a secondary bacterial infection may also be present due to lowered immunity and stress on the system. Mechanisms of transmission of colds and influenza include aerosolization of virus-laden respiratory secretions and direct mucous membrane contact with virus from contaminated hands, other skin surfaces, and even furniture. Touching the eyes and nose with contaminated hands will increase transmission rates. There is current evidence that psychological stress can increase the risk and severity of viral infections. (4) , (5)

Similarly, influenza is an acute respiratory illness that occurs in annual outbreaks of varying severity. The virus infects the respiratory tract and is highly contagious, producing systemic symptoms early in the illness. Influenza viruses belong to the family Orthomyxoviridae and are divided into three types (Types A, B, and C).Type C infection usually causes either a very mild respiratory illness or no symptoms at all; it does not cause epidemics and does not have the severe public health impact that influenza types A and B do. Efforts to control the impact of influenza are aimed at types A and B. Influenza viruses continually change over time, usually by mutation. Influenza is very contagious and is spread by contact with an infected person. A person is contagious from about two days before symptoms occur until about the fifth day of the illness.

No methods have been developed to effectively prevent colds and influenza to date. Vaccines are not likely to be effective in preventing the common cold, due to the large number of immuno-types and the lack of solid immunity to re-infection with the other viruses. Treatment of colds and influenza is largely symptomatic, with antibiotics not recommended for use in the therapy of uncomplicated colds and influenza due to the viral nature of the disease.

A recent resurgence in the use of nutritional supplements including herbs, vitamins, minerals, and homeopathic medicines has provided new options for the support of cold and flu symptoms as well as for prevention. These agents may not prevent a cold, but may result in less severe symptoms and a decreased need for nonprescription or prescription medications. The purpose of herbs and nutritional agents are to improve host defenses before and during viral invasion. By improving immune functionality and host integrity, the individual stands a better chance of fighting off the infection, or at the very least reducing the severity of symptoms associated with a cold or the flu.


World Health Organization, March 19, 2007.

  • Avian flu (H5N1) totals from 2003- March 19, 2007 are 280 confirmed cases and 169 deaths. That's a death rate of more than 55 per cent, which is considered high for a viral illness.
  • Indonesia had the highest number of cases in 2006 with 56 confirmed cases and 46 deaths.

Influenza: National Institute for Health/Center for Disease Control, Vital Health Statistics, 2001.

    108,000,000 cases are reported annually in the U.S. 1,765 deaths are due to influenza annually. 357 million report restricted activity days. 75 million work days are lost each year. 10,000 to 30,000 people with diabetes die from complications resulting from the flu and pneumonia.

Common Cold: National Institute for Health/Center for Disease Control, Vital Health Statistics Series 10.

    62 million cases are reported yearly. 52.2 million of these affect children under the age of 17. 22 million school days are lost annually. 75% of colds suffered by children under 5 are medically attended.

Signs and Symptoms

[span class=alert]The following list does not insure the presence of this health condition. Please see the text and your healthcare professional for more information.[/span]

Symptoms of colds may include rhinorrhea, sneezing, nasal stuffiness, throat clearing, postnasal drip, cough, and nasal obstruction. A sore throat and/or cough may also be present. Other symptoms may include pharyngitis, laryngitis, headache, malaise, and fever, usually in various combinations. Ear and sinus problems are often present as well.

Influenza virus can produce clinical syndromes, such as the common cold, pharyngitis, tracheobronchitis, and pneumonia. Symptoms of influenza include chills, fever, headache, muscular aches/pains, malaise and fatigue, and lack of appetite.

Common Cold

  • "Runny" nose
  • Sneezing
  • Nasal stuffiness
  • Throat clearing
  • Postnasal drip
  • Cough
  • Sore throat
  • Inflamed nasal membranes
  • Sore throat
  • Laryngitis
  • Headache
  • Discomfort
  • Fatigue
  • Fever
  • Ear and sinus problems

Influenza or Flu

  • Chills
  • Fever
  • Headache
  • Muscular aches/pains
  • Discomfort
  • Fatigue
  • Lack of appetite

Treatment Options


Vaccination- According to the CDC, the influenza vaccine has been shown to reduce hospitalization by about 70 percent and death by about 85 percent in the non-institutionalized elderly. Among nursing home residents, the flu vaccine can reduce the risk of hospitalization by about 50 percent, the risk of pneumonia by about 60 percent, and the risk of death by 75 to 80 percent. However, influenza in the elderly is still ranked as one of the top ten causes of death in those over the age of 65 years. (6) Documented side effects from administration of influenza vaccines range from mental confusion, fatigue, circulatory problems, headache, sexual disturbances, and gastrointestinal complaints among others. (7) About 5-10 percent may experience mild side effects, such as headache or low-grade fever for a short period of time. For some elderly, the vaccine does not provide adequate protection, and therefore, are still at risk and should consider taking additional steps to be prepared for flu season.

Antiviral Agents- Other drugs known as antiviral agents may be considered by your physician. These include:

Oseltamivir Phosphate


Amantadine HCI

Rimantadine HCI

Nutritional Suplementation


Many food sources today do not contain the vitamins and minerals that they did in the past, and in particular, the elderly population is known to have suspect nutrient status. Recommending a multiple vitamin daily is the first choice for prevention. Studies support that elderly individuals taking a daily multiple vitamin have a reduced risk for colds and flu. (8)

Vitamin C

Studies on the effects of vitamin C on the common cold indicate that while supplementation does not affect the incidence of the common cold, vitamin C can reduce both the severity and duration of cold symptoms by an average of 23 percent. (9) , (10) Vitamin C may be utilized at 4 - 6 times the normal rate by white blood cells during active infection. Vitamin C’s role in colds and influenza is not curative, but it does support a healthy immune system response to viral and bacterial infection.


Human clinical trials on the use of zinc in colds and influenza indicate that zinc gluconate lozenges may be effective in reducing the duration and severity of symptoms. (11) In a meta-analysis of seven randomized, controlled trials, it was determined that zinc gluconate lozenges have a therapeutic effect in treating the common cold. (12)

Sterols (Sitosterol) and Sterolins (Sitosterolin)

There are many chemical constituents (termed phytochemicals) found in plant medicines that have beneficial pharmacological effects in humans. Some bioactive phytochemicals include tannins, resins, polysaccharides, saponins, glycosides, and volatile oils among others. Recent literature has reported that two of these phytochemicals, sterols and sterolins (plant "fats"), occur naturally in fruits, vegetables, seeds, and nuts and, have clinically beneficial effects in human subjects in many conditions.

Sterol is found in all plant-based foods, and sterolin is a glucoside moiety joined to the sterol chemical structure. Both sterols and sterolins were identified as early as 1922. In the natural state, these plant "fats" are bound to the fibers of the plant, making the sterols and sterolins difficult to be absorbed during the normal transit of digested food through our gut. Seeds are the richest source of the sterols and sterolins, but are usually removed during processing by the food industry.

Plant sterols and sterolins have been reported to be effective adjunctive agents in the management and treatment of disease states such as high cholesterol levels, benign prostatic hyperplasia, pulmonary tuberculosis, and stress-induced immune suppression and HIV among others. (13) , (14) , (15) , (16) , (17) Some of the most promising uses of these plant "fats" is in the management of autoimmune disorders such as lupus, multiple sclerosis, rheumatoid arthritis, and myasthenia gravis. Of note is that the sterols should be combined with sterolin in order to be an effective agent for the immune system. (18)

Sterols and sterolins have been reported to modulate the function of T-cells, significantly enhancing the proliferation of the CD-4 TH-1 cells and increasing the production of the interleukin 2 (IL2) and gamma-interferon (FN-g and IFN-y). (19) These results indicate that sterols and sterolins are adaptogenic in that they modulate the immune and stress response.

Care should be taken if an individual is taking immunosuppressive agents. Based on pharmacology, If an individual is taking hypocholesterolemic agents concurrently with plant sterols and sterolins, a dosage adjustment in the pharmaceutical medication may be necessary.

Vitamin E

Researchers investigated the role of vitamin E supplementation and the occurrence of colds in the elderly. The results showed that vitamin E showed no improvement in the number of infections or the number of days being sick. However, it was shown that vitamin E supplementation did reduce the occurrence of the common cold. (20)

Herbal Suplementation


Echinacea is one of the most popular herbs in the world. It has non-specific stimulatory effects on the immune system. (21) Research has reported that echinacea may stimulate the alternate and complementary pathway of the immune system, activating white blood cells and macrophages for use in the management and treatment of colds and influenza. (22) , (23) Echinacea is also reported to possess antimicrobial activity against bacteria, fungi, and viruses. (24) There have been several randomized, double-blind, placebo controlled clinical studies in Europe conducted on human subjects using echinacea. Benefits reported include improving the symptoms and severity of colds and influenza. (25) , (26) , (27) , (28) , (29)

It should be noted that the immuno-modulating polysaccharides found in the echinacea plant are NOT soluble in alcohol. Therefore, when using an echinacea product, it is best not to use alcohol liquid extracts of echinacea due to precipitation of the polysaccharide content and possible loss of the immuno-modulatory properties.


Goldenseal has a long history of use in the United States as a medicinal herb, traditionally for GI disturbances, as an anti-infective agent, and to stimulate bile flow. (30) , (31) , (32) It was initially used by Native Americans and gained popularity with the eclectic medical movement from the 1850's to the 1940's. The most current use of goldenseal is for colds and influenza. Combinations of goldenseal and echinacea are one of the leading selling herbal supplements in the U.S. market today. Due to the mucous membrane tonifying and the antibacterial properties of the alkaloids in goldenseal, this herbal medicine may be useful in managing symptoms associated with colds and influenza. (33) , (34)


Elder has been used as a food and medicinal agent for thousands of years. The flower and berry have been traditionally used in the prevention and treatment of colds, influenza, chronic nasal inflammation, and sinusitis. (35) An extract of the berries of the black elder (Sambucus nigra) has been reported to inhibit the ability of several strains of influenza virus to replicate. It does this by coating the spike-like projections on the virus, preventing it from injecting protein into the host cell membrane. In one study using a liquid extract of elder berry, 90 percent of the individuals with symptoms of influenza B were asymptomatic in 2-3 days, while individuals on placebo did not recover for at least 6 days. (36)


The Chinese have valued astragalus for centuries for its immune-enhancing and adaptogenic properties. As an adaptogen, it may modify and improve the body’s response to stress through action on the adrenal cortex. (37) , (38) Studies have reported that astragalus promotes regeneration of cells in the bronchi after viral infection. (39) This potential benefit could help with the lingering phase of bronchial weakness as seen in some individuals with colds and influenza. Astragalus should be able to be taken safely for several months without the risk of suppressing immunologic function. Astragalus enhances the effects of interferon, and may act not only to improve resistance to colds but decrease the duration of a cold. (40)

Larch Arabinogalactan

Larix is a purified extract of the bark from the Western larch tree. It contains the phytochemical arabinogalactan, an immunomodulating polysaccharide that is also found in Echinacea spp. Larix has also been used with positive success in children, specifically in otitis media. (41)

Diet & Lifestyle

    Drink at least 6-8 glasses of quality water daily. Avoid refined sugars. Take in clear broth and soups. Take steps to reduce chronic stress. Get adequate rest. Try to eat more nutrient rich foods, especially fruits and vegetables. Reduce sugar intake. Exercise regularly.


  1. National Institute of Allergy and Infectious Disease, National Institute of Health. Common Cold Fact Sheet. Mar2001.
  2. National Institute of Allergy and Infectious Disease, National Institute of Health. Common Cold Fact Sheet. Mar2001.
  3. View Abstract: Makela MJ, et al. Viruses and bacteria in the etiology of the common cold. J Clin Microbiol. 1998;36(2):539-42.
  4. View Abstract: Padgett DA, et al. Stress exacerbates age-related decrements in the immune response to an experimental influenza viral infection. J Gerontol A Biol Sci Med Sci. 1998;53(5):B347-53.
  5. Gruzelier J, et al. Mind-body influences on immunity: lateralized control, stress, individual differences predictors, and prophylaxis. Ann N Y Acad Sci. 1998;851:487-94.
  6. National Vital Statistics Reports, Vol 48, No. 11. Jul2000.
  7. Palache AM. Influenza subunit vaccine - ten years experience. Eur J Clin Res. 1992;3:117-138.
  8. View Abstract: Girodon F, Galan P, Monget AL. Impact of Trace Elements and Vitamin Supplementation on Immunity and Infections in Institutionalized Elderly Patients. Arch Intern Med. 1999;159:748-754.
  9. View Abstract: Hemila H. Does vitamin C alleviate the symptoms of the common cold? - A review of current evidence. Scan J Infec Dis. 1994;26:1-6.
  10. View Abstract: Van Straten M, Josling P. Preventing the common cold with a vitamin C supplement: a double-blind, placebo-controlled survey. Adv Ther. May2002;19(3):151-9.
  11. View Abstract: Garland ML, et al. The role of zinc lozenges in the treatment of the common cold. Ann Pharmacother. 1998;32:63-69.
  12. View Abstract: Marshall S. Zinc gluconate and the common cold. Review of randomized controlled trials. Can Fam Physician. 1998;44:1037-42.
  13. Bouic PJD. Immunomodulation in HIV/AIDS: The Tygerberg/Stellenbosch university experience. AIDS Bulletin. Sept1997;6(3):18-20.
  14. Clerici M, Bevilacqua M, Vago T, et al. An Immunoendocrinological Hypothesis of HIV Infection. Lancet. Jun1994;343:1552-1553.
  15. View Abstract: Donald PR, Lamprecht JH, Freestone M, et al. A Randomized Placebo-controlled Trial of the Efficacy of Beta-sitosterol and Its Glucoside as Adjuvants in the Treatment of Pulmonary Tuberculosis. International Journal of Tuberculosis and Lung Disease. Jul1997;1(5):518-522.
  16. View Abstract: Berges RR, Windele J, Trampisch HJ, et al. Randomized, Placebo-controlled, Double-blind Clinical Trial of B-sitosterol in Patients with Benign Prostatic Hyperplasia. Lancet. Jun1995;345(8964):1529-32.
  17. View Abstract: Plat J, Kerckhoffs DA, Mensink RP. Therapeutic Potential of Plant Sterols and Stanols. Curr Opin Lipidol. Dec2000;11(6):571-6.
  18. View Abstract: Plat J, Kerckhoffs DA, Mensink RP. Therapeutic Potential of Plant Sterols and Stanols. Curr Opin Lipidol. Dec2000;11(6):571-6.
  19. View Abstract: Plat J, Kerckhoffs DA, Mensink RP. Therapeutic Potential of Plant Sterols and Stanols. Curr Opin Lipidol. Dec2000;11(6):571-6.
  20. View Abstract: Meydani SN, et al. Vitamin E and Respiratory Tract Infections in Elderly Nursing Home Residents. JAMA. Aug 2004;292(7):828-836.
  21. Snow JM. Echinacea (Moench) spp. Asteraceae. Protocol Journal of Botanical Medicine. 1996;2(2):18-23.
  22. View Abstract: Vomel VT. The effect of a nonspecific immunostimulant on the phagocytosis of erythrocytes and ink by the reticulohistiocyte system in the isolated, perfused liver of rats of various ages. Arzneim Forsch/Drug Res. 1984;34:691-95.
  23. View Abstract: See DM, et al. In vitro effects of echinacea and ginseng on natural killer and antibody-dependent cell cytotoxicity in healthy subjects and chronic fatigue syndrome or acquired immunodeficiency syndrome patients. Immunopharmacology. 1997;35(3):229-35.
  24. Wichtl M, in N. A. Bisset, ed. Herbal Drugs and Phytopharmaceuticals. Stuttgart: Scientific Press; 1994:182-84.
  25. Schoneberger D. The influence of immune-stimulating effects of pressed juice from Echinacea purpurea on the course and severity of colds. Forum Immunologie. 1992;8:2-12.
  26. Braunig B, et al. Echinacea purpurea root for strengthening the immune response in flu-like infections. Zeitschrift Phytother. 1992;13:7-13.
  27. Braunig B, et al. Therapeutical experiences with Echinacea pallida for influenza-like infections. Naturheilpraxis. 1993;1:72-75.
  28. View Abstract: Grimm W, et al. A Randomized Controlled Trial of the Effect of Fluid Extract of Echinacea purpurea on the Incidence and Severity of Colds and Respiratory Infections. Am J Med. Feb1999;106(2):138-43.
  29. View Abstract: Brinkeborn RM, et al. Echinaforce and Other Echinacea Fresh Plant Preparations in the Treatment of the Common Cold. A Randomized, Placebo Controlled, Double-blind Clinical Trial. Phytomedicine. Mar1999;6(1):1-6.
  30. Sabir M, et al. Study of some pharmacological actions of berberine. Indian J Physiol Pharmacol. 1971;15(3):111-32.
  31. Newall CA, et al. Herbal Medicines: A Guide for Health Care Professionals. London, England: The Pharmaceutical Press; 1996:151-52.
  32. View Abstract: Berberine. Altern Med Rev. Apr 2000;5(2):175-7.
  33. View Abstract: Zhang MF, et al. Antidiarrheal and anti-inflammatory effects of berberine. Chung Kuo Yao Li Hsueh Pao. 1989;10(2):174-76.
  34. View Abstract: Sun D, et al. Berberine sulfate blocks adherence of Streptococcus pyogenes to epithelial cells, fibronectin, and hexadecane. Antimicrobial Agent and Chemotherapy. 1988;32(9):1370-1374.
  35. Newall CA, et al. Herbal Medicines: A Guide for Health Care Professionals. London, England: The Pharmaceutical Press; 1996:151-52.
  36. View Abstract: Zakay-Rones Z, et al. Inhibition of several strains of influenza virus in-vitro and reduction of symptoms by an elderberry extract (Sambucus nigra L.) during an outbreak of influenza B in Panama. J Altern Complement Med. 1995;1(4):361-369.
  37. Chang CY, et al. Effects of Astragalus membranaceus on enhancement of mouse natural killer cell activity. Chung Kuo I Hsueh Ko Hsueh Yuan Hsueh Pao. 1983;5(4):231-34.
  38. View Abstract: Zhao KS, et al. Positive modulating action of shengmaisan with Astragalus membranaceus on anti-tumor activity of LAK cells. Immunopharmacology. 1990;20(3):471.
  39. Chang H, et al. Pharmacology and Application of Chinese Materia Medica. Singapore; Chinese University of Hong Kong. World Scientific. 1987:4.
  40. Geng CS, et al. Advances in immuno-pharmacological studies on Astragalus membranaceus. Chung Hsi I Chieh Ho Tsa Chih. 1986;6(1):62-64.
  41. View Abstract: Kelly GS. Larch Arabinogalactan: Clinical Relevance of a Novel Immune-enhancing Polysaccharide. Altern Med Rev. Apr1999;4(2):96-103.