Four Natural Flu Defenses

Whether you choose to be vaccinated or not, you need more protection. In this article we shall cover some simple lifestyle measures that will boost the efficiency of two cells in the immune system that destroy flu viruses. Like air force bombers, killer T- lymphocytes and natural killer cells (NK cells) act by destroying viruses and cancer cells. Memory B- and T-lymphocytes possess immunological memory. Because they remember past exposure to viruses, they enable the body to activate a much swifter immune response. Antibodies also play an important role.

Cultivate a positive attitude. Replace negative thoughts with positive interventions. Major depression reduces NK cells’ effectiveness. A persistent negative outlook erodes both the ability of the NK cells and killer T-lymphocytes to destroy viruses and cancer cells. The emotions and reactive thinking common in depression—helplessness, loneliness, hopelessness, lack of social support, and unhealthy suppression of these feelings—not only depress the mind but also the immune system.

Chronic and acute stresses decrease the number and function of natural killer cells. Stress reduces their ability to make interferon, a chemical that substantially decreases viral replication. However, problem-solving techniques and coping skills improve NK activity in stressed individuals. When individuals, for example, are exposed to a big stressor (i.e. taking a medical school exam), if they have high emotional stability and low anxiety, stress actually improves NK cell activity.(1) On the other hand, the same stress can result in a significant decline in NK cells if the individual possesses high anxiety and low emotional stability. Fortunately, realistic optimism, self-confidence, trust, and faith improve the natural killer cells’ job performance.(2)

When you have been exposed to a virus or your immune system is down, sip some immune-boosting tea and take time to count your blessings.

One caveat here: since chronic stress, acute stress, or even perceived stress reduce the antibody response from the flu vaccine, –if you are going to get a flu shot, don’t get it until you are rested and more relaxed.

Get adequate amounts of vitamin D. Vitamin D combats influenza. Before the flu season begins, find out your vitamin D status. A study involving 18, 883 participants, 12 years and older, found that people with the lowest blood level of vitamin D reported having significantly more recent colds or flu. The analysis adjusted for demographics and clinical factors (season, body mass index, smoking history, asthma, and chronic obstructive pulmonary disease).(3)

Vitamin D helps to activate your inactive immune responses. Your body produces natural antibiotic-like compounds called antimicrobial peptides in the white blood cells. Bio-active Vitamin D dramatically increases the activity of these antimicrobial compounds found in white blood cells and epithelial cells of the respiratory tract.(4)

Unfortunately, nutritional epidemiologists estimate that as many as 50% of North Americans and Europeans have an insufficient amount of Vitamin D. To solve this problem, get at least 20 minutes of sunlight a day and consider taking a vitamin D supplement, especially if you are indoors most of the day, are elderly, or have dark skin, as these factors substantially increase your risk for vitamin D deficiency.

Engage in daily exercise. Moderate exercise helps to protect us from influenza. Hong Kong researchers discovered that individuals who never or seldom exercised increased their risk of dying from influenza by 5½ to 8 times. In contrast, those who exercised frequently decreased their risk by 4 to nearly 6½ times.(5) Moderate exercise also helps to slow down the aging of the immune system. Cardiovascular exercise significantly improves the efficacy of the flu vaccine in sedentary, elderly individuals even 24 weeks after the shot is given.(6)

Strenuous, exhaustive exercise however, decreases the number of natural killers and T-lymphocytes and their activity is depressed for several days.(7) Heavy exertion increases an athlete’s risk of upper respiratory tract infection (URTI) because of negative changes in immune function and elevation of the stress hormones, epinephrine, and cortisol.(8)

Practice temperance. Temperance is abstinence from all injurious agents and harmful habits, and the moderate use of all good substances and activities. Alcohol suppresses natural killer cell activity.

Smoking decreases natural killer cell activity and cessation of smoking improves it. Smoking dries out your nasal passages and paralyzes cilia, the delicate hairs that line the inside of your nose and lungs and help keep germs out of the body. Just one cigarette can paralyze cilia for as long as 30 to 40 minutes. Even exposure to another’s tobacco smoke can increase susceptibility to upper respiratory and lung infections. Deep breathing improves the circulation of the blood consequently improving the circulation of the white blood cells.

Get enough sleep. Partial sleep deprivation reduces natural killer cell activity temporarily. Even a modest sleep deprivation for part of the night can reduce the killing ability of the natural killer cells by almost 30% (9) and promote inflammation. Sleep deprivation can also reduce the effectiveness of flu vaccines.

Author: Elizabeth J. Hall

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2. Hall, E.J., Bolstering Your Immune System. The Journal of Health and Healing, 23(3):16-19.

3. Ginde, AA. Association between Serum 25-Hydroxyvitamin D Level and Upper Respiratory Tract Infection in the Third National Health and Nutrition Examination Survey. Arch Intern Med. 2009; 169(4):384-390.

4. Cannell J.J., et al, Epidemic influenza and vitamin D. Epidemiol Infect, 134(6):1129-40, 2006.

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6. Woods, JA. Cardiovascular exercise training extends influenza vaccine seroprotection in sedentary older adults: the immune function intervention trial. J Am Geriatr Society. 2009 Dec. 57(12):2183-9.

7. Shek, P.N., Strenuous exercise and immunological changes; a multiple-time-point analysis of leukocytes subset CD4/CD8 ratio, immunoglobulin production and NK cell response. Int JSports Med, 16(7):466-67, 1996.

8. Nieman D.C. Exercise and resistance to infections. Cn J Physiol Pharmacol, 76(5):573-80, 1998.

9. Irwin, M., et al, Partial Sleep Deprivation Reduces Natural Killer Cell Activity in Humans,